diff --git a/.buildkite/docker-compose.yaml b/.buildkite/docker-compose.yaml
new file mode 100644
index 0000000000..73d5ccdd5e
--- /dev/null
+++ b/.buildkite/docker-compose.yaml
@@ -0,0 +1,23 @@
+version: '3.1'
+
+services:
+
+  postgres:
+    image: postgres:${POSTGRES_VERSION?}
+    environment:
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_INITDB_ARGS: "--lc-collate C --lc-ctype C --encoding UTF8"
+    command: -c fsync=off
+
+  testenv:
+    image: python:${PYTHON_VERSION?}
+    depends_on:
+      - postgres
+    env_file: docker-compose-env
+    environment:
+      SYNAPSE_POSTGRES_HOST: postgres
+      SYNAPSE_POSTGRES_USER: postgres
+      SYNAPSE_POSTGRES_PASSWORD: postgres
+    working_dir: /src
+    volumes:
+      - ${BUILDKITE_BUILD_CHECKOUT_PATH}:/src
diff --git a/.buildkite/pipeline.yml b/.buildkite/pipeline.yml
index c3171c00c8..47273fb61e 100644
--- a/.buildkite/pipeline.yml
+++ b/.buildkite/pipeline.yml
@@ -1,3 +1,15 @@
+# This is just a dummy entry (the `x-yaml-aliases` key is not an official pipeline key, and will be ignored by BuildKite)
+# that we use only to store YAML anchors (`&xxx`), that we plan to use and reference later in the YAML file (using `*xxx`)
+# without having to copy/paste the same values over and over.
+# Note: keys like `agent`, `env`, … used here are totally arbitrary; the only point is to define various separate `&xxx` anchors there.
+#
+x-yaml-aliases:
+  commands:
+    - &trial_setup |
+      # Install additional packages that are not part of buildpack-deps / python images.
+      apt-get update && apt-get install -y xmlsec1
+      python -m pip install tox
+
 env:
   COVERALLS_REPO_TOKEN: wsJWOby6j0uCYFiCes3r0XauxO27mx8lD
 
@@ -79,7 +91,7 @@ steps:
 
   - label: ":python: 3.5 / SQLite"
     command:
-      - "python -m pip install tox"
+      - *trial_setup
       - "tox -e py35,combine"
     env:
       TRIAL_FLAGS: "-j 2"
@@ -102,7 +114,7 @@ steps:
 
   - label: ":python: 3.6 / SQLite"
     command:
-      - "python -m pip install tox"
+      - *trial_setup
       - "tox -e py36,combine"
     env:
       TRIAL_FLAGS: "-j 2"
@@ -125,7 +137,7 @@ steps:
 
   - label: ":python: 3.7 / SQLite"
     command:
-      - "python -m pip install tox"
+      - *trial_setup
       - "tox -e py37,combine"
     env:
       TRIAL_FLAGS: "-j 2"
@@ -151,18 +163,17 @@ steps:
       queue: "medium"
     env:
       TRIAL_FLAGS: "-j 8"
+      PYTHON_VERSION: "3.5"
+      POSTGRES_VERSION: "9.5"
     command:
-      - "bash -c 'python -m pip install tox && python -m tox -e py35-postgres,combine'"
+      - *trial_setup
+      - "python -m tox -e py35-postgres,combine"
     plugins:
-      - matrix-org/download#v1.1.0:
-          urls:
-            - https://raw.githubusercontent.com/matrix-org/synapse-dinsic/dinsic/.buildkite/docker-compose.py35.pg95.yaml
-            - https://raw.githubusercontent.com/matrix-org/synapse-dinsic/dinsic/.buildkite/docker-compose-env
-      - docker-compose#v2.1.0:
+      - docker-compose#v3.7.0:
           run: testenv
           config:
-            - /tmp/download-${BUILDKITE_BUILD_ID}/docker-compose.py35.pg95.yaml
-      - artifacts#v1.2.0:
+            - .buildkite/docker-compose.yaml
+      - artifacts#v1.3.0:
           upload: [ "_trial_temp/*/*.log" ]
 #      - matrix-org/coveralls#v1.0:
 #          parallel: "true"
@@ -178,18 +189,17 @@ steps:
       queue: "medium"
     env:
       TRIAL_FLAGS: "-j 8"
+      PYTHON_VERSION: "3.7"
+      POSTGRES_VERSION: "11"
     command:
-      - "bash -c 'python -m pip install tox && python -m tox -e py37-postgres,combine'"
+      - *trial_setup
+      - "tox -e py37-postgres,combine"
     plugins:
-      - matrix-org/download#v1.1.0:
-          urls:
-            - https://raw.githubusercontent.com/matrix-org/synapse-dinsic/dinsic/.buildkite/docker-compose.py37.pg11.yaml
-            - https://raw.githubusercontent.com/matrix-org/synapse-dinsic/dinsic/.buildkite/docker-compose-env
-      - docker-compose#v2.1.0:
+      - docker-compose#v3.7.0:
           run: testenv
           config:
-            - /tmp/download-${BUILDKITE_BUILD_ID}/docker-compose.py37.pg11.yaml
-      - artifacts#v1.2.0:
+            - .buildkite/docker-compose.yaml
+      - artifacts#v1.3.0:
           upload: [ "_trial_temp/*/*.log" ]
 #      - matrix-org/coveralls#v1.0:
 #          parallel: "true"
@@ -205,18 +215,17 @@ steps:
       queue: "medium"
     env:
       TRIAL_FLAGS: "-j 8"
+      PYTHON_VERSION: "3.8"
+      POSTGRES_VERSION: "12"
     command:
-      - "bash -c 'python -m pip install tox && python -m tox -e py38-postgres,combine'"
+      - *trial_setup
+      - "tox -e py38-postgres,combine"
     plugins:
-      - matrix-org/download#v1.1.0:
-          urls:
-            - https://raw.githubusercontent.com/matrix-org/synapse-dinsic/dinsic/.buildkite/docker-compose.py38.pg12.yaml
-            - https://raw.githubusercontent.com/matrix-org/synapse-dinsic/dinsic/.buildkite/docker-compose-env
-      - docker-compose#v2.1.0:
+      - docker-compose#v3.7.0:
           run: testenv
           config:
-            - /tmp/download-${BUILDKITE_BUILD_ID}/docker-compose.py38.pg12.yaml
-      - artifacts#v1.2.0:
+            - .buildkite/docker-compose.yaml
+      - artifacts#v1.3.0:
           upload: [ "_trial_temp/*/*.log" ]
 #      - matrix-org/coveralls#v1.0:
 #          parallel: "true"
diff --git a/.buildkite/scripts/test_old_deps.sh b/.buildkite/scripts/test_old_deps.sh
index cdb77b556c..9905c4bc4f 100755
--- a/.buildkite/scripts/test_old_deps.sh
+++ b/.buildkite/scripts/test_old_deps.sh
@@ -6,7 +6,7 @@
 set -ex
 
 apt-get update
-apt-get install -y python3.5 python3.5-dev python3-pip libxml2-dev libxslt-dev zlib1g-dev tox
+apt-get install -y python3.5 python3.5-dev python3-pip libxml2-dev libxslt-dev xmlsec1 zlib1g-dev tox
 
 export LANG="C.UTF-8"
 
diff --git a/.buildkite/test_db.db b/.buildkite/test_db.db
index 361369a581..a0d9f16a75 100644
Binary files a/.buildkite/test_db.db and b/.buildkite/test_db.db differ
diff --git a/.buildkite/worker-blacklist b/.buildkite/worker-blacklist
index fd98cbbaf6..5975cb98cf 100644
--- a/.buildkite/worker-blacklist
+++ b/.buildkite/worker-blacklist
@@ -1,41 +1,10 @@
 # This file serves as a blacklist for SyTest tests that we expect will fail in
 # Synapse when run under worker mode. For more details, see sytest-blacklist.
 
-Message history can be paginated
-
 Can re-join room if re-invited
 
-The only membership state included in an initial sync is for all the senders in the timeline
-
-Local device key changes get to remote servers
-
-If remote user leaves room we no longer receive device updates
-
-Forgotten room messages cannot be paginated
-
-Inbound federation can get public room list
-
-Members from the gap are included in gappy incr LL sync
-
-Leaves are present in non-gapped incremental syncs
-
-Old leaves are present in gapped incremental syncs
-
-User sees updates to presence from other users in the incremental sync.
-
-Gapped incremental syncs include all state changes
-
-Old members are included in gappy incr LL sync if they start speaking
-
 # new failures as of https://github.com/matrix-org/sytest/pull/732
 Device list doesn't change if remote server is down
-Remote servers cannot set power levels in rooms without existing powerlevels
-Remote servers should reject attempts by non-creators to set the power levels
 
 # https://buildkite.com/matrix-dot-org/synapse/builds/6134#6f67bf47-e234-474d-80e8-c6e1868b15c5
 Server correctly handles incoming m.device_list_update
-
-# this fails reliably with a torture level of 100 due to https://github.com/matrix-org/synapse/issues/6536
-Outbound federation requests missing prev_events and then asks for /state_ids and resolves the state
-
-Can get rooms/{roomId}/members at a given point
diff --git a/.circleci/config.yml b/.circleci/config.yml
index 5bd2ab2b76..088da55735 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,22 +1,34 @@
-version: 2
+version: 2.1
 jobs:
   dockerhubuploadrelease:
-    machine: true
+    docker:
+      - image: docker:git
     steps:
       - checkout
-      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:${CIRCLE_TAG} .
+      - docker_prepare
       - run: docker login --username $DOCKER_HUB_USERNAME --password $DOCKER_HUB_PASSWORD
-      - run: docker push matrixdotorg/synapse:${CIRCLE_TAG}
+      - docker_build:
+          tag: -t matrixdotorg/synapse:${CIRCLE_TAG}
+          platforms: linux/amd64
+      - docker_build:
+          tag: -t matrixdotorg/synapse:${CIRCLE_TAG}
+          platforms: linux/amd64,linux/arm/v7,linux/arm64
+
   dockerhubuploadlatest:
-    machine: true
+    docker:
+      - image: docker:git
     steps:
       - checkout
-      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:latest .
+      - docker_prepare
       - run: docker login --username $DOCKER_HUB_USERNAME --password $DOCKER_HUB_PASSWORD
-      - run: docker push matrixdotorg/synapse:latest
+      - docker_build:
+          tag: -t matrixdotorg/synapse:latest
+          platforms: linux/amd64
+      - docker_build:
+          tag: -t matrixdotorg/synapse:latest
+          platforms: linux/amd64,linux/arm/v7,linux/arm64
 
 workflows:
-  version: 2
   build:
     jobs:
       - dockerhubuploadrelease:
@@ -29,3 +41,37 @@ workflows:
           filters:
             branches:
               only: master
+
+commands:
+  docker_prepare:
+    description: Sets up a remote docker server, downloads the buildx cli plugin, and enables multiarch images
+    parameters:
+      buildx_version:
+        type: string
+        default: "v0.4.1"
+    steps:
+      - setup_remote_docker:
+          # 19.03.13 was the most recent available on circleci at the time of
+          # writing.
+          version: 19.03.13
+      - run: apk add --no-cache curl
+      - run: mkdir -vp ~/.docker/cli-plugins/ ~/dockercache
+      - run: curl --silent -L "https://github.com/docker/buildx/releases/download/<< parameters.buildx_version >>/buildx-<< parameters.buildx_version >>.linux-amd64" > ~/.docker/cli-plugins/docker-buildx
+      - run: chmod a+x ~/.docker/cli-plugins/docker-buildx
+      # install qemu links in /proc/sys/fs/binfmt_misc on the docker instance running the circleci job
+      - run: docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+      # create a context named `builder` for the builds
+      - run: docker context create builder
+      # create a buildx builder using the new context, and set it as the default
+      - run: docker buildx create builder --use
+
+  docker_build:
+    description: Builds and pushed images to dockerhub using buildx
+    parameters:
+      platforms:
+        type: string
+        default: linux/amd64
+      tag:
+        type: string
+    steps:
+      - run: docker buildx build -f docker/Dockerfile --push --platform << parameters.platforms >> --label gitsha1=${CIRCLE_SHA1} << parameters.tag >> --progress=plain .
diff --git a/.gitignore b/.gitignore
index af36c00cfa..9bb5bdd647 100644
--- a/.gitignore
+++ b/.gitignore
@@ -21,6 +21,7 @@ _trial_temp*/
 /.python-version
 /*.signing.key
 /env/
+/.venv*/
 /homeserver*.yaml
 /logs
 /media_store/
diff --git a/CHANGES.md b/CHANGES.md
index 38a0814bbf..0cecb83498 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,412 @@
+Synapse 1.24.0 (2020-12-09)
+===========================
+
+Due to the two security issues highlighted below, server administrators are
+encouraged to update Synapse. We are not aware of these vulnerabilities being
+exploited in the wild.
+
+Security advisory
+-----------------
+
+The following issues are fixed in v1.23.1 and v1.24.0.
+
+- There is a denial of service attack
+  ([CVE-2020-26257](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26257))
+  against the federation APIs in which future events will not be correctly sent
+  to other servers over federation. This affects all servers that participate in
+  open federation. (Fixed in [#8776](https://github.com/matrix-org/synapse/pull/8776)).
+
+- Synapse may be affected by OpenSSL
+  [CVE-2020-1971](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-1971).
+  Synapse administrators should ensure that they have the latest versions of
+  the cryptography Python package installed.
+
+To upgrade Synapse along with the cryptography package:
+
+* Administrators using the [`matrix.org` Docker
+  image](https://hub.docker.com/r/matrixdotorg/synapse/) or the [Debian/Ubuntu
+  packages from
+  `matrix.org`](https://github.com/matrix-org/synapse/blob/master/INSTALL.md#matrixorg-packages)
+  should ensure that they have version 1.24.0 or 1.23.1 installed: these images include
+  the updated packages.
+* Administrators who have [installed Synapse from
+  source](https://github.com/matrix-org/synapse/blob/master/INSTALL.md#installing-from-source)
+  should upgrade the cryptography package within their virtualenv by running:
+  ```sh
+  <path_to_virtualenv>/bin/pip install 'cryptography>=3.3'
+  ```
+* Administrators who have installed Synapse from distribution packages should
+  consult the information from their distributions.
+
+Internal Changes
+----------------
+
+- Add a maximum version for pysaml2 on Python 3.5. ([\#8898](https://github.com/matrix-org/synapse/issues/8898))
+
+
+Synapse 1.23.1 (2020-12-09)
+===========================
+
+Due to the two security issues highlighted below, server administrators are
+encouraged to update Synapse. We are not aware of these vulnerabilities being
+exploited in the wild.
+
+Security advisory
+-----------------
+
+The following issues are fixed in v1.23.1 and v1.24.0.
+
+- There is a denial of service attack
+  ([CVE-2020-26257](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-26257))
+  against the federation APIs in which future events will not be correctly sent
+  to other servers over federation. This affects all servers that participate in
+  open federation. (Fixed in [#8776](https://github.com/matrix-org/synapse/pull/8776)).
+
+- Synapse may be affected by OpenSSL
+  [CVE-2020-1971](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-1971).
+  Synapse administrators should ensure that they have the latest versions of
+  the cryptography Python package installed.
+
+To upgrade Synapse along with the cryptography package:
+
+* Administrators using the [`matrix.org` Docker
+  image](https://hub.docker.com/r/matrixdotorg/synapse/) or the [Debian/Ubuntu
+  packages from
+  `matrix.org`](https://github.com/matrix-org/synapse/blob/master/INSTALL.md#matrixorg-packages)
+  should ensure that they have version 1.24.0 or 1.23.1 installed: these images include
+  the updated packages.
+* Administrators who have [installed Synapse from
+  source](https://github.com/matrix-org/synapse/blob/master/INSTALL.md#installing-from-source)
+  should upgrade the cryptography package within their virtualenv by running:
+  ```sh
+  <path_to_virtualenv>/bin/pip install 'cryptography>=3.3'
+  ```
+* Administrators who have installed Synapse from distribution packages should
+  consult the information from their distributions.
+
+Bugfixes
+--------
+
+- Fix a bug in some federation APIs which could lead to unexpected behaviour if different parameters were set in the URI and the request body. ([\#8776](https://github.com/matrix-org/synapse/issues/8776))
+
+
+Internal Changes
+----------------
+
+- Add a maximum version for pysaml2 on Python 3.5. ([\#8898](https://github.com/matrix-org/synapse/issues/8898))
+
+
+Synapse 1.24.0rc2 (2020-12-04)
+==============================
+
+Bugfixes
+--------
+
+- Fix a regression in v1.24.0rc1 which failed to allow SAML mapping providers which were unable to redirect users to an additional page. ([\#8878](https://github.com/matrix-org/synapse/issues/8878))
+
+
+Internal Changes
+----------------
+
+- Add support for the `prometheus_client` newer than 0.9.0. Contributed by Jordan Bancino. ([\#8875](https://github.com/matrix-org/synapse/issues/8875))
+
+
+Synapse 1.24.0rc1 (2020-12-02)
+==============================
+
+Features
+--------
+
+- Add admin API for logging in as a user. ([\#8617](https://github.com/matrix-org/synapse/issues/8617))
+- Allow specification of the SAML IdP if the metadata returns multiple IdPs. ([\#8630](https://github.com/matrix-org/synapse/issues/8630))
+- Add support for re-trying generation of a localpart for OpenID Connect mapping providers. ([\#8801](https://github.com/matrix-org/synapse/issues/8801), [\#8855](https://github.com/matrix-org/synapse/issues/8855))
+- Allow the `Date` header through CORS. Contributed by Nicolas Chamo. ([\#8804](https://github.com/matrix-org/synapse/issues/8804))
+- Add a config option, `push.group_by_unread_count`, which controls whether unread message counts in push notifications are defined as "the number of rooms with unread messages" or "total unread messages". ([\#8820](https://github.com/matrix-org/synapse/issues/8820))
+- Add `force_purge` option to delete-room admin api. ([\#8843](https://github.com/matrix-org/synapse/issues/8843))
+
+
+Bugfixes
+--------
+
+- Fix a bug where appservices may be sent an excessive amount of read receipts and presence. Broke in v1.22.0. ([\#8744](https://github.com/matrix-org/synapse/issues/8744))
+- Fix a bug in some federation APIs which could lead to unexpected behaviour if different parameters were set in the URI and the request body. ([\#8776](https://github.com/matrix-org/synapse/issues/8776))
+- Fix a bug where synctl could spawn duplicate copies of a worker. Contributed by Waylon Cude. ([\#8798](https://github.com/matrix-org/synapse/issues/8798))
+- Allow per-room profiles to be used for the server notice user. ([\#8799](https://github.com/matrix-org/synapse/issues/8799))
+- Fix a bug where logging could break after a call to SIGHUP. ([\#8817](https://github.com/matrix-org/synapse/issues/8817))
+- Fix `register_new_matrix_user` failing with "Bad Request" when trailing slash is included in server URL. Contributed by @angdraug. ([\#8823](https://github.com/matrix-org/synapse/issues/8823))
+- Fix a minor long-standing bug in login, where we would offer the `password` login type if a custom auth provider supported it, even if password login was disabled. ([\#8835](https://github.com/matrix-org/synapse/issues/8835))
+- Fix a long-standing bug which caused Synapse to require unspecified parameters during user-interactive authentication. ([\#8848](https://github.com/matrix-org/synapse/issues/8848))
+- Fix a bug introduced in v1.20.0 where the user-agent and IP address reported during user registration for CAS, OpenID Connect, and SAML were of the wrong form. ([\#8784](https://github.com/matrix-org/synapse/issues/8784))
+
+
+Improved Documentation
+----------------------
+
+- Clarify the usecase for a msisdn delegate. Contributed by Adrian Wannenmacher. ([\#8734](https://github.com/matrix-org/synapse/issues/8734))
+- Remove extraneous comma from JSON example in User Admin API docs. ([\#8771](https://github.com/matrix-org/synapse/issues/8771))
+- Update `turn-howto.md` with troubleshooting notes. ([\#8779](https://github.com/matrix-org/synapse/issues/8779))
+- Fix the example on how to set the `Content-Type` header in nginx for the Client Well-Known URI. ([\#8793](https://github.com/matrix-org/synapse/issues/8793))
+- Improve the documentation for the admin API to list all media in a room with respect to encrypted events. ([\#8795](https://github.com/matrix-org/synapse/issues/8795))
+- Update the formatting of the `push` section of the homeserver config file to better align with the [code style guidelines](https://github.com/matrix-org/synapse/blob/develop/docs/code_style.md#configuration-file-format). ([\#8818](https://github.com/matrix-org/synapse/issues/8818))
+- Improve documentation how to configure prometheus for workers. ([\#8822](https://github.com/matrix-org/synapse/issues/8822))
+- Update example prometheus console. ([\#8824](https://github.com/matrix-org/synapse/issues/8824))
+
+
+Deprecations and Removals
+-------------------------
+
+- Remove old `/_matrix/client/*/admin` endpoints which were deprecated since Synapse 1.20.0. ([\#8785](https://github.com/matrix-org/synapse/issues/8785))
+- Disable pretty printing JSON responses for curl. Users who want pretty-printed output should use [jq](https://stedolan.github.io/jq/) in combination with curl. Contributed by @tulir. ([\#8833](https://github.com/matrix-org/synapse/issues/8833))
+
+
+Internal Changes
+----------------
+
+- Simplify the way the `HomeServer` object caches its internal attributes. ([\#8565](https://github.com/matrix-org/synapse/issues/8565), [\#8851](https://github.com/matrix-org/synapse/issues/8851))
+- Add an example and documentation for clock skew to the SAML2 sample configuration to allow for clock/time difference between the homserver and IdP. Contributed by @localguru. ([\#8731](https://github.com/matrix-org/synapse/issues/8731))
+- Generalise `RoomMemberHandler._locally_reject_invite` to apply to more flows than just invite. ([\#8751](https://github.com/matrix-org/synapse/issues/8751))
+- Generalise `RoomStore.maybe_store_room_on_invite` to handle other, non-invite membership events. ([\#8754](https://github.com/matrix-org/synapse/issues/8754))
+- Refactor test utilities for injecting HTTP requests. ([\#8757](https://github.com/matrix-org/synapse/issues/8757), [\#8758](https://github.com/matrix-org/synapse/issues/8758), [\#8759](https://github.com/matrix-org/synapse/issues/8759), [\#8760](https://github.com/matrix-org/synapse/issues/8760), [\#8761](https://github.com/matrix-org/synapse/issues/8761), [\#8777](https://github.com/matrix-org/synapse/issues/8777))
+- Consolidate logic between the OpenID Connect and SAML code. ([\#8765](https://github.com/matrix-org/synapse/issues/8765))
+- Use `TYPE_CHECKING` instead of magic `MYPY` variable. ([\#8770](https://github.com/matrix-org/synapse/issues/8770))
+- Add a commandline script to sign arbitrary json objects. ([\#8772](https://github.com/matrix-org/synapse/issues/8772))
+- Minor log line improvements for the SSO mapping code used to generate Matrix IDs from SSO IDs. ([\#8773](https://github.com/matrix-org/synapse/issues/8773))
+- Add additional error checking for OpenID Connect and SAML mapping providers. ([\#8774](https://github.com/matrix-org/synapse/issues/8774), [\#8800](https://github.com/matrix-org/synapse/issues/8800))
+- Add type hints to HTTP abstractions. ([\#8806](https://github.com/matrix-org/synapse/issues/8806), [\#8812](https://github.com/matrix-org/synapse/issues/8812))
+- Remove unnecessary function arguments and add typing to several membership replication classes. ([\#8809](https://github.com/matrix-org/synapse/issues/8809))
+- Optimise the lookup for an invite from another homeserver when trying to reject it. ([\#8815](https://github.com/matrix-org/synapse/issues/8815))
+- Add tests for `password_auth_provider`s. ([\#8819](https://github.com/matrix-org/synapse/issues/8819))
+- Drop redundant database index on `event_json`. ([\#8845](https://github.com/matrix-org/synapse/issues/8845))
+- Simplify `uk.half-shot.msc2778.login.application_service` login handler. ([\#8847](https://github.com/matrix-org/synapse/issues/8847))
+- Refactor `password_auth_provider` support code. ([\#8849](https://github.com/matrix-org/synapse/issues/8849))
+- Add missing `ordering` to background database updates. ([\#8850](https://github.com/matrix-org/synapse/issues/8850))
+- Allow for specifying a room version when creating a room in unit tests via `RestHelper.create_room_as`. ([\#8854](https://github.com/matrix-org/synapse/issues/8854))
+
+
+Synapse 1.23.0 (2020-11-18)
+===========================
+
+This release changes the way structured logging is configured. See the [upgrade notes](UPGRADE.rst#upgrading-to-v1230) for details.
+
+**Note**: We are aware of a trivially exploitable denial of service vulnerability in versions of Synapse prior to 1.20.0. Complete details will be disclosed on Monday, November 23rd. If you have not upgraded recently, please do so.
+
+Bugfixes
+--------
+
+- Fix a dependency versioning bug in the Dockerfile that prevented Synapse from starting. ([\#8767](https://github.com/matrix-org/synapse/issues/8767))
+
+
+Synapse 1.23.0rc1 (2020-11-13)
+==============================
+
+Features
+--------
+
+- Add a push rule that highlights when a jitsi conference is created in a room. ([\#8286](https://github.com/matrix-org/synapse/issues/8286))
+- Add an admin api to delete a single file or files that were not used for a defined time from server. Contributed by @dklimpel. ([\#8519](https://github.com/matrix-org/synapse/issues/8519))
+- Split admin API for reported events (`GET /_synapse/admin/v1/event_reports`) into detail and list endpoints. This is a breaking change to #8217 which was introduced in Synapse v1.21.0. Those who already use this API should check their scripts. Contributed by @dklimpel. ([\#8539](https://github.com/matrix-org/synapse/issues/8539))
+- Support generating structured logs via the standard logging configuration. ([\#8607](https://github.com/matrix-org/synapse/issues/8607), [\#8685](https://github.com/matrix-org/synapse/issues/8685))
+- Add an admin API to allow server admins to list users' pushers. Contributed by @dklimpel. ([\#8610](https://github.com/matrix-org/synapse/issues/8610), [\#8689](https://github.com/matrix-org/synapse/issues/8689))
+- Add an admin API `GET /_synapse/admin/v1/users/<user_id>/media` to get information about uploaded media. Contributed by @dklimpel. ([\#8647](https://github.com/matrix-org/synapse/issues/8647))
+- Add an admin API for local user media statistics. Contributed by @dklimpel. ([\#8700](https://github.com/matrix-org/synapse/issues/8700))
+- Add `displayname` to Shared-Secret Registration for admins. ([\#8722](https://github.com/matrix-org/synapse/issues/8722))
+
+
+Bugfixes
+--------
+
+- Fix fetching of E2E cross signing keys over federation when only one of the master key and device signing key is cached already. ([\#8455](https://github.com/matrix-org/synapse/issues/8455))
+- Fix a bug where Synapse would blindly forward bad responses from federation to clients when retrieving profile information. ([\#8580](https://github.com/matrix-org/synapse/issues/8580))
+- Fix a bug where the account validity endpoint would silently fail if the user ID did not have an expiration time. It now returns a 400 error. ([\#8620](https://github.com/matrix-org/synapse/issues/8620))
+- Fix email notifications for invites without local state. ([\#8627](https://github.com/matrix-org/synapse/issues/8627))
+- Fix handling of invalid group IDs to return a 400 rather than log an exception and return a 500. ([\#8628](https://github.com/matrix-org/synapse/issues/8628))
+- Fix handling of User-Agent headers that are invalid UTF-8, which caused user agents of users to not get correctly recorded. ([\#8632](https://github.com/matrix-org/synapse/issues/8632))
+- Fix a bug in the `joined_rooms` admin API if the user has never joined any rooms. The bug was introduced, along with the API, in v1.21.0. ([\#8643](https://github.com/matrix-org/synapse/issues/8643))
+- Fix exception during handling multiple concurrent requests for remote media when using multiple media repositories. ([\#8682](https://github.com/matrix-org/synapse/issues/8682))
+- Fix bug that prevented Synapse from recovering after losing connection to the database. ([\#8726](https://github.com/matrix-org/synapse/issues/8726))
+- Fix bug where the `/_synapse/admin/v1/send_server_notice` API could send notices to non-notice rooms. ([\#8728](https://github.com/matrix-org/synapse/issues/8728))
+- Fix PostgreSQL port script fails when DB has no backfilled events. Broke in v1.21.0. ([\#8729](https://github.com/matrix-org/synapse/issues/8729))
+- Fix PostgreSQL port script to correctly handle foreign key constraints. Broke in v1.21.0. ([\#8730](https://github.com/matrix-org/synapse/issues/8730))
+- Fix PostgreSQL port script so that it can be run again after a failure. Broke in v1.21.0. ([\#8755](https://github.com/matrix-org/synapse/issues/8755))
+
+
+Improved Documentation
+----------------------
+
+- Instructions for Azure AD in the OpenID Connect documentation. Contributed by peterk. ([\#8582](https://github.com/matrix-org/synapse/issues/8582))
+- Improve the sample configuration for single sign-on providers. ([\#8635](https://github.com/matrix-org/synapse/issues/8635))
+- Fix the filepath of Dex's example config and the link to Dex's Getting Started guide in the OpenID Connect docs. ([\#8657](https://github.com/matrix-org/synapse/issues/8657))
+- Note support for Python 3.9. ([\#8665](https://github.com/matrix-org/synapse/issues/8665))
+- Minor updates to docs on running tests. ([\#8666](https://github.com/matrix-org/synapse/issues/8666))
+- Interlink prometheus/grafana documentation. ([\#8667](https://github.com/matrix-org/synapse/issues/8667))
+- Notes on SSO logins and media_repository worker. ([\#8701](https://github.com/matrix-org/synapse/issues/8701))
+- Document experimental support for running multiple event persisters. ([\#8706](https://github.com/matrix-org/synapse/issues/8706))
+- Add information regarding the various sources of, and expected contributions to, Synapse's documentation to `CONTRIBUTING.md`. ([\#8714](https://github.com/matrix-org/synapse/issues/8714))
+- Migrate documentation `docs/admin_api/event_reports` to markdown. ([\#8742](https://github.com/matrix-org/synapse/issues/8742))
+- Add some helpful hints to the README for new Synapse developers. Contributed by @chagai95. ([\#8746](https://github.com/matrix-org/synapse/issues/8746))
+
+
+Internal Changes
+----------------
+
+- Optimise `/createRoom` with multiple invited users. ([\#8559](https://github.com/matrix-org/synapse/issues/8559))
+- Implement and use an `@lru_cache` decorator. ([\#8595](https://github.com/matrix-org/synapse/issues/8595))
+- Don't instansiate Requester directly. ([\#8614](https://github.com/matrix-org/synapse/issues/8614))
+- Type hints for `RegistrationStore`. ([\#8615](https://github.com/matrix-org/synapse/issues/8615))
+- Change schema to support access tokens belonging to one user but granting access to another. ([\#8616](https://github.com/matrix-org/synapse/issues/8616))
+- Remove unused OPTIONS handlers. ([\#8621](https://github.com/matrix-org/synapse/issues/8621))
+- Run `mypy` as part of the lint.sh script. ([\#8633](https://github.com/matrix-org/synapse/issues/8633))
+- Correct Synapse's PyPI package name in the OpenID Connect installation instructions. ([\#8634](https://github.com/matrix-org/synapse/issues/8634))
+- Catch exceptions during initialization of `password_providers`. Contributed by Nicolai Søborg. ([\#8636](https://github.com/matrix-org/synapse/issues/8636))
+- Fix typos and spelling errors in the code. ([\#8639](https://github.com/matrix-org/synapse/issues/8639))
+- Reduce number of OpenTracing spans started. ([\#8640](https://github.com/matrix-org/synapse/issues/8640), [\#8668](https://github.com/matrix-org/synapse/issues/8668), [\#8670](https://github.com/matrix-org/synapse/issues/8670))
+- Add field `total` to device list in admin API. ([\#8644](https://github.com/matrix-org/synapse/issues/8644))
+- Add more type hints to the application services code. ([\#8655](https://github.com/matrix-org/synapse/issues/8655), [\#8693](https://github.com/matrix-org/synapse/issues/8693))
+- Tell Black to format code for Python 3.5. ([\#8664](https://github.com/matrix-org/synapse/issues/8664))
+- Don't pull event from DB when handling replication traffic. ([\#8669](https://github.com/matrix-org/synapse/issues/8669))
+- Abstract some invite-related code in preparation for landing knocking. ([\#8671](https://github.com/matrix-org/synapse/issues/8671), [\#8688](https://github.com/matrix-org/synapse/issues/8688))
+- Clarify representation of events in logfiles. ([\#8679](https://github.com/matrix-org/synapse/issues/8679))
+- Don't require `hiredis` package to be installed to run unit tests. ([\#8680](https://github.com/matrix-org/synapse/issues/8680))
+- Fix typing info on cache call signature to accept `on_invalidate`. ([\#8684](https://github.com/matrix-org/synapse/issues/8684))
+- Fail tests if they do not await coroutines. ([\#8690](https://github.com/matrix-org/synapse/issues/8690))
+- Improve start time by adding an index to `e2e_cross_signing_keys.stream_id`. ([\#8694](https://github.com/matrix-org/synapse/issues/8694))
+- Re-organize the structured logging code to separate the TCP transport handling from the JSON formatting. ([\#8697](https://github.com/matrix-org/synapse/issues/8697))
+- Use Python 3.8 in Docker images by default. ([\#8698](https://github.com/matrix-org/synapse/issues/8698))
+- Remove the "draft" status of the Room Details Admin API. ([\#8702](https://github.com/matrix-org/synapse/issues/8702))
+- Improve the error returned when a non-string displayname or avatar_url is used when updating a user's profile. ([\#8705](https://github.com/matrix-org/synapse/issues/8705))
+- Block attempts by clients to send server ACLs, or redactions of server ACLs, that would result in the local server being blocked from the room. ([\#8708](https://github.com/matrix-org/synapse/issues/8708))
+- Add metrics the allow the local sysadmin to track 3PID `/requestToken` requests. ([\#8712](https://github.com/matrix-org/synapse/issues/8712))
+- Consolidate duplicated lists of purged tables that are checked in tests. ([\#8713](https://github.com/matrix-org/synapse/issues/8713))
+- Add some `mdui:UIInfo` element examples for `saml2_config` in the homeserver config. ([\#8718](https://github.com/matrix-org/synapse/issues/8718))
+- Improve the error message returned when a remote server incorrectly sets the `Content-Type` header in response to a JSON request. ([\#8719](https://github.com/matrix-org/synapse/issues/8719))
+- Speed up repeated state resolutions on the same room by caching event ID to auth event ID lookups. ([\#8752](https://github.com/matrix-org/synapse/issues/8752))
+
+
+Synapse 1.22.1 (2020-10-30)
+===========================
+
+Bugfixes
+--------
+
+- Fix a bug where an appservice may not be forwarded events for a room it was recently invited to. Broke in v1.22.0. ([\#8676](https://github.com/matrix-org/synapse/issues/8676))
+- Fix `Object of type frozendict is not JSON serializable` exceptions when using third-party event rules. Broke in v1.22.0. ([\#8678](https://github.com/matrix-org/synapse/issues/8678))
+
+
+Synapse 1.22.0 (2020-10-27)
+===========================
+
+No significant changes.
+
+
+Synapse 1.22.0rc2 (2020-10-26)
+==============================
+
+Bugfixes
+--------
+
+- Fix bugs where ephemeral events were not sent to appservices. Broke in v1.22.0rc1. ([\#8648](https://github.com/matrix-org/synapse/issues/8648), [\#8656](https://github.com/matrix-org/synapse/issues/8656))
+- Fix `user_daily_visits` table to not have duplicate rows per user/device due to multiple user agents. Broke in v1.22.0rc1. ([\#8654](https://github.com/matrix-org/synapse/issues/8654))
+
+Synapse 1.22.0rc1 (2020-10-22)
+==============================
+
+Features
+--------
+
+- Add a configuration option for always using the "userinfo endpoint" for OpenID Connect. This fixes support for some identity providers, e.g. GitLab. Contributed by Benjamin Koch. ([\#7658](https://github.com/matrix-org/synapse/issues/7658))
+- Add ability for `ThirdPartyEventRules` modules to query and manipulate whether a room is in the public rooms directory. ([\#8292](https://github.com/matrix-org/synapse/issues/8292), [\#8467](https://github.com/matrix-org/synapse/issues/8467))
+- Add support for olm fallback keys ([MSC2732](https://github.com/matrix-org/matrix-doc/pull/2732)). ([\#8312](https://github.com/matrix-org/synapse/issues/8312), [\#8501](https://github.com/matrix-org/synapse/issues/8501))
+- Add support for running background tasks in a separate worker process. ([\#8369](https://github.com/matrix-org/synapse/issues/8369), [\#8458](https://github.com/matrix-org/synapse/issues/8458), [\#8489](https://github.com/matrix-org/synapse/issues/8489), [\#8513](https://github.com/matrix-org/synapse/issues/8513), [\#8544](https://github.com/matrix-org/synapse/issues/8544), [\#8599](https://github.com/matrix-org/synapse/issues/8599))
+- Add support for device dehydration ([MSC2697](https://github.com/matrix-org/matrix-doc/pull/2697)). ([\#8380](https://github.com/matrix-org/synapse/issues/8380))
+- Add support for [MSC2409](https://github.com/matrix-org/matrix-doc/pull/2409), which allows sending typing, read receipts, and presence events to appservices. ([\#8437](https://github.com/matrix-org/synapse/issues/8437), [\#8590](https://github.com/matrix-org/synapse/issues/8590))
+- Change default room version to "6", per [MSC2788](https://github.com/matrix-org/matrix-doc/pull/2788). ([\#8461](https://github.com/matrix-org/synapse/issues/8461))
+- Add the ability to send non-membership events into a room via the `ModuleApi`. ([\#8479](https://github.com/matrix-org/synapse/issues/8479))
+- Increase default upload size limit from 10M to 50M. Contributed by @Akkowicz. ([\#8502](https://github.com/matrix-org/synapse/issues/8502))
+- Add support for modifying event content in `ThirdPartyRules` modules. ([\#8535](https://github.com/matrix-org/synapse/issues/8535), [\#8564](https://github.com/matrix-org/synapse/issues/8564))
+
+
+Bugfixes
+--------
+
+- Fix a longstanding bug where invalid ignored users in account data could break clients. ([\#8454](https://github.com/matrix-org/synapse/issues/8454))
+- Fix a bug where backfilling a room with an event that was missing the `redacts` field would break. ([\#8457](https://github.com/matrix-org/synapse/issues/8457))
+- Don't attempt to respond to some requests if the client has already disconnected. ([\#8465](https://github.com/matrix-org/synapse/issues/8465))
+- Fix message duplication if something goes wrong after persisting the event. ([\#8476](https://github.com/matrix-org/synapse/issues/8476))
+- Fix incremental sync returning an incorrect `prev_batch` token in timeline section, which when used to paginate returned events that were included in the incremental sync. Broken since v0.16.0. ([\#8486](https://github.com/matrix-org/synapse/issues/8486))
+- Expose the `uk.half-shot.msc2778.login.application_service` to clients from the login API. This feature was added in v1.21.0, but was not exposed as a potential login flow. ([\#8504](https://github.com/matrix-org/synapse/issues/8504))
+- Fix error code for `/profile/{userId}/displayname` to be `M_BAD_JSON`. ([\#8517](https://github.com/matrix-org/synapse/issues/8517))
+- Fix a bug introduced in v1.7.0 that could cause Synapse to insert values from non-state `m.room.retention` events into the `room_retention` database table. ([\#8527](https://github.com/matrix-org/synapse/issues/8527))
+- Fix not sending events over federation when using sharded event writers. ([\#8536](https://github.com/matrix-org/synapse/issues/8536))
+- Fix a long standing bug where email notifications for encrypted messages were blank. ([\#8545](https://github.com/matrix-org/synapse/issues/8545))
+- Fix increase in the number of `There was no active span...` errors logged when using OpenTracing. ([\#8567](https://github.com/matrix-org/synapse/issues/8567))
+- Fix a bug that prevented errors encountered during execution of the `synapse_port_db` from being correctly printed. ([\#8585](https://github.com/matrix-org/synapse/issues/8585))
+- Fix appservice transactions to only include a maximum of 100 persistent and 100 ephemeral events. ([\#8606](https://github.com/matrix-org/synapse/issues/8606))
+
+
+Updates to the Docker image
+---------------------------
+
+- Added multi-arch support (arm64,arm/v7) for the docker images. Contributed by @maquis196. ([\#7921](https://github.com/matrix-org/synapse/issues/7921))
+- Add support for passing commandline args to the synapse process. Contributed by @samuel-p. ([\#8390](https://github.com/matrix-org/synapse/issues/8390))
+
+
+Improved Documentation
+----------------------
+
+- Update the directions for using the manhole with coroutines. ([\#8462](https://github.com/matrix-org/synapse/issues/8462))
+- Improve readme by adding new shield.io badges. ([\#8493](https://github.com/matrix-org/synapse/issues/8493))
+- Added note about docker in manhole.md regarding which ip address to bind to. Contributed by @Maquis196. ([\#8526](https://github.com/matrix-org/synapse/issues/8526))
+- Document the new behaviour of the `allowed_lifetime_min` and `allowed_lifetime_max` settings in the room retention configuration. ([\#8529](https://github.com/matrix-org/synapse/issues/8529))
+
+
+Deprecations and Removals
+-------------------------
+
+- Drop unused `device_max_stream_id` table. ([\#8589](https://github.com/matrix-org/synapse/issues/8589))
+
+
+Internal Changes
+----------------
+
+- Check for unreachable code with mypy. ([\#8432](https://github.com/matrix-org/synapse/issues/8432))
+- Add unit test for event persister sharding. ([\#8433](https://github.com/matrix-org/synapse/issues/8433))
+- Allow events to be sent to clients sooner when using sharded event persisters. ([\#8439](https://github.com/matrix-org/synapse/issues/8439), [\#8488](https://github.com/matrix-org/synapse/issues/8488), [\#8496](https://github.com/matrix-org/synapse/issues/8496), [\#8499](https://github.com/matrix-org/synapse/issues/8499))
+- Configure `public_baseurl` when using demo scripts. ([\#8443](https://github.com/matrix-org/synapse/issues/8443))
+- Add SQL logging on queries that happen during startup. ([\#8448](https://github.com/matrix-org/synapse/issues/8448))
+- Speed up unit tests when using PostgreSQL. ([\#8450](https://github.com/matrix-org/synapse/issues/8450))
+- Remove redundant database loads of stream_ordering for events we already have. ([\#8452](https://github.com/matrix-org/synapse/issues/8452))
+- Reduce inconsistencies between codepaths for membership and non-membership events. ([\#8463](https://github.com/matrix-org/synapse/issues/8463))
+- Combine `SpamCheckerApi` with the more generic `ModuleApi`. ([\#8464](https://github.com/matrix-org/synapse/issues/8464))
+- Additional testing for `ThirdPartyEventRules`. ([\#8468](https://github.com/matrix-org/synapse/issues/8468))
+- Add `-d` option to `./scripts-dev/lint.sh` to lint files that have changed since the last git commit. ([\#8472](https://github.com/matrix-org/synapse/issues/8472))
+- Unblacklist some sytests. ([\#8474](https://github.com/matrix-org/synapse/issues/8474))
+- Include the log level in the phone home stats. ([\#8477](https://github.com/matrix-org/synapse/issues/8477))
+- Remove outdated sphinx documentation, scripts and configuration. ([\#8480](https://github.com/matrix-org/synapse/issues/8480))
+- Clarify error message when plugin config parsers raise an error. ([\#8492](https://github.com/matrix-org/synapse/issues/8492))
+- Remove the deprecated `Handlers` object. ([\#8494](https://github.com/matrix-org/synapse/issues/8494))
+- Fix a threadsafety bug in unit tests. ([\#8497](https://github.com/matrix-org/synapse/issues/8497))
+- Add user agent to user_daily_visits table. ([\#8503](https://github.com/matrix-org/synapse/issues/8503))
+- Add type hints to various parts of the code base. ([\#8407](https://github.com/matrix-org/synapse/issues/8407), [\#8505](https://github.com/matrix-org/synapse/issues/8505), [\#8507](https://github.com/matrix-org/synapse/issues/8507), [\#8547](https://github.com/matrix-org/synapse/issues/8547), [\#8562](https://github.com/matrix-org/synapse/issues/8562), [\#8609](https://github.com/matrix-org/synapse/issues/8609))
+- Remove unused code from the test framework. ([\#8514](https://github.com/matrix-org/synapse/issues/8514))
+- Apply some internal fixes to the `HomeServer` class to make its code more idiomatic and statically-verifiable. ([\#8515](https://github.com/matrix-org/synapse/issues/8515))
+- Factor out common code between `RoomMemberHandler._locally_reject_invite` and `EventCreationHandler.create_event`. ([\#8537](https://github.com/matrix-org/synapse/issues/8537))
+- Improve database performance by executing more queries without starting transactions. ([\#8542](https://github.com/matrix-org/synapse/issues/8542))
+- Rename `Cache` to `DeferredCache`, to better reflect its purpose. ([\#8548](https://github.com/matrix-org/synapse/issues/8548))
+- Move metric registration code down into `LruCache`. ([\#8561](https://github.com/matrix-org/synapse/issues/8561), [\#8591](https://github.com/matrix-org/synapse/issues/8591))
+- Replace `DeferredCache` with the lighter-weight `LruCache` where possible. ([\#8563](https://github.com/matrix-org/synapse/issues/8563))
+- Add virtualenv-generated folders to `.gitignore`. ([\#8566](https://github.com/matrix-org/synapse/issues/8566))
+- Add `get_immediate` method to `DeferredCache`. ([\#8568](https://github.com/matrix-org/synapse/issues/8568))
+- Fix mypy not properly checking across the codebase, additionally, fix a typing assertion error in `handlers/auth.py`. ([\#8569](https://github.com/matrix-org/synapse/issues/8569))
+- Fix `synmark` benchmark runner. ([\#8571](https://github.com/matrix-org/synapse/issues/8571))
+- Modify `DeferredCache.get()` to return `Deferred`s instead of `ObservableDeferred`s. ([\#8572](https://github.com/matrix-org/synapse/issues/8572))
+- Adjust a protocol-type definition to fit `sqlite3` assertions. ([\#8577](https://github.com/matrix-org/synapse/issues/8577))
+- Support macOS on the `synmark` benchmark runner. ([\#8578](https://github.com/matrix-org/synapse/issues/8578))
+- Update `mypy` static type checker to 0.790. ([\#8583](https://github.com/matrix-org/synapse/issues/8583), [\#8600](https://github.com/matrix-org/synapse/issues/8600))
+- Re-organize the structured logging code to separate the TCP transport handling from the JSON formatting. ([\#8587](https://github.com/matrix-org/synapse/issues/8587))
+- Remove extraneous unittest logging decorators from unit tests. ([\#8592](https://github.com/matrix-org/synapse/issues/8592))
+- Minor optimisations in caching code. ([\#8593](https://github.com/matrix-org/synapse/issues/8593), [\#8594](https://github.com/matrix-org/synapse/issues/8594))
+
+
 Synapse 1.21.2 (2020-10-15)
 ===========================
 
@@ -6098,8 +6507,8 @@ Changes in synapse 0.5.1 (2014-11-26)
 
 See UPGRADES.rst for specific instructions on how to upgrade.
 
-> -   Fix bug where we served up an Event that did not match its signatures.
-> -   Fix regression where we no longer correctly handled the case where a homeserver receives an event for a room it doesn\'t recognise (but is in.)
+-   Fix bug where we served up an Event that did not match its signatures.
+-   Fix regression where we no longer correctly handled the case where a homeserver receives an event for a room it doesn\'t recognise (but is in.)
 
 Changes in synapse 0.5.0 (2014-11-19)
 =====================================
@@ -6110,44 +6519,44 @@ This release also changes the internal database schemas and so requires servers
 
 Homeserver:
 
-:   -   Add authentication and authorization to the federation protocol. Events are now signed by their originating homeservers.
-    -   Implement the new authorization model for rooms.
-    -   Split out web client into a seperate repository: matrix-angular-sdk.
-    -   Change the structure of PDUs.
-    -   Fix bug where user could not join rooms via an alias containing 4-byte UTF-8 characters.
-    -   Merge concept of PDUs and Events internally.
-    -   Improve logging by adding request ids to log lines.
-    -   Implement a very basic room initial sync API.
-    -   Implement the new invite/join federation APIs.
+-   Add authentication and authorization to the federation protocol. Events are now signed by their originating homeservers.
+-   Implement the new authorization model for rooms.
+-   Split out web client into a seperate repository: matrix-angular-sdk.
+-   Change the structure of PDUs.
+-   Fix bug where user could not join rooms via an alias containing 4-byte UTF-8 characters.
+-   Merge concept of PDUs and Events internally.
+-   Improve logging by adding request ids to log lines.
+-   Implement a very basic room initial sync API.
+-   Implement the new invite/join federation APIs.
 
 Webclient:
 
-:   -   The webclient has been moved to a seperate repository.
+-   The webclient has been moved to a seperate repository.
 
 Changes in synapse 0.4.2 (2014-10-31)
 =====================================
 
 Homeserver:
 
-:   -   Fix bugs where we did not notify users of correct presence updates.
-    -   Fix bug where we did not handle sub second event stream timeouts.
+-   Fix bugs where we did not notify users of correct presence updates.
+-   Fix bug where we did not handle sub second event stream timeouts.
 
 Webclient:
 
-:   -   Add ability to click on messages to see JSON.
-    -   Add ability to redact messages.
-    -   Add ability to view and edit all room state JSON.
-    -   Handle incoming redactions.
-    -   Improve feedback on errors.
-    -   Fix bugs in mobile CSS.
-    -   Fix bugs with desktop notifications.
+-   Add ability to click on messages to see JSON.
+-   Add ability to redact messages.
+-   Add ability to view and edit all room state JSON.
+-   Handle incoming redactions.
+-   Improve feedback on errors.
+-   Fix bugs in mobile CSS.
+-   Fix bugs with desktop notifications.
 
 Changes in synapse 0.4.1 (2014-10-17)
 =====================================
 
 Webclient:
 
-:   -   Fix bug with display of timestamps.
+-   Fix bug with display of timestamps.
 
 Changes in synpase 0.4.0 (2014-10-17)
 =====================================
@@ -6160,8 +6569,8 @@ You will also need an updated syutil and config. See UPGRADES.rst.
 
 Homeserver:
 
-:   -   Sign federation transactions to assert strong identity over federation.
-    -   Rename timestamp keys in PDUs and events from \'ts\' and \'hsob\_ts\' to \'origin\_server\_ts\'.
+-   Sign federation transactions to assert strong identity over federation.
+-   Rename timestamp keys in PDUs and events from \'ts\' and \'hsob\_ts\' to \'origin\_server\_ts\'.
 
 Changes in synapse 0.3.4 (2014-09-25)
 =====================================
@@ -6170,48 +6579,48 @@ This version adds support for using a TURN server. See docs/turn-howto.rst on ho
 
 Homeserver:
 
-:   -   Add support for redaction of messages.
-    -   Fix bug where inviting a user on a remote home server could take up to 20-30s.
-    -   Implement a get current room state API.
-    -   Add support specifying and retrieving turn server configuration.
+-   Add support for redaction of messages.
+-   Fix bug where inviting a user on a remote home server could take up to 20-30s.
+-   Implement a get current room state API.
+-   Add support specifying and retrieving turn server configuration.
 
 Webclient:
 
-:   -   Add button to send messages to users from the home page.
-    -   Add support for using TURN for VoIP calls.
-    -   Show display name change messages.
-    -   Fix bug where the client didn\'t get the state of a newly joined room until after it has been refreshed.
-    -   Fix bugs with tab complete.
-    -   Fix bug where holding down the down arrow caused chrome to chew 100% CPU.
-    -   Fix bug where desktop notifications occasionally used \"Undefined\" as the display name.
-    -   Fix more places where we sometimes saw room IDs incorrectly.
-    -   Fix bug which caused lag when entering text in the text box.
+-   Add button to send messages to users from the home page.
+-   Add support for using TURN for VoIP calls.
+-   Show display name change messages.
+-   Fix bug where the client didn\'t get the state of a newly joined room until after it has been refreshed.
+-   Fix bugs with tab complete.
+-   Fix bug where holding down the down arrow caused chrome to chew 100% CPU.
+-   Fix bug where desktop notifications occasionally used \"Undefined\" as the display name.
+-   Fix more places where we sometimes saw room IDs incorrectly.
+-   Fix bug which caused lag when entering text in the text box.
 
 Changes in synapse 0.3.3 (2014-09-22)
 =====================================
 
 Homeserver:
 
-:   -   Fix bug where you continued to get events for rooms you had left.
+-   Fix bug where you continued to get events for rooms you had left.
 
 Webclient:
 
-:   -   Add support for video calls with basic UI.
-    -   Fix bug where one to one chats were named after your display name rather than the other person\'s.
-    -   Fix bug which caused lag when typing in the textarea.
-    -   Refuse to run on browsers we know won\'t work.
-    -   Trigger pagination when joining new rooms.
-    -   Fix bug where we sometimes didn\'t display invitations in recents.
-    -   Automatically join room when accepting a VoIP call.
-    -   Disable outgoing and reject incoming calls on browsers we don\'t support VoIP in.
-    -   Don\'t display desktop notifications for messages in the room you are non-idle and speaking in.
+-   Add support for video calls with basic UI.
+-   Fix bug where one to one chats were named after your display name rather than the other person\'s.
+-   Fix bug which caused lag when typing in the textarea.
+-   Refuse to run on browsers we know won\'t work.
+-   Trigger pagination when joining new rooms.
+-   Fix bug where we sometimes didn\'t display invitations in recents.
+-   Automatically join room when accepting a VoIP call.
+-   Disable outgoing and reject incoming calls on browsers we don\'t support VoIP in.
+-   Don\'t display desktop notifications for messages in the room you are non-idle and speaking in.
 
 Changes in synapse 0.3.2 (2014-09-18)
 =====================================
 
 Webclient:
 
-:   -   Fix bug where an empty \"bing words\" list in old accounts didn\'t send notifications when it should have done.
+-   Fix bug where an empty \"bing words\" list in old accounts didn\'t send notifications when it should have done.
 
 Changes in synapse 0.3.1 (2014-09-18)
 =====================================
@@ -6220,8 +6629,8 @@ This is a release to hotfix v0.3.0 to fix two regressions.
 
 Webclient:
 
-:   -   Fix a regression where we sometimes displayed duplicate events.
-    -   Fix a regression where we didn\'t immediately remove rooms you were banned in from the recents list.
+-   Fix a regression where we sometimes displayed duplicate events.
+-   Fix a regression where we didn\'t immediately remove rooms you were banned in from the recents list.
 
 Changes in synapse 0.3.0 (2014-09-18)
 =====================================
@@ -6230,91 +6639,91 @@ See UPGRADE for information about changes to the client server API, including br
 
 Homeserver:
 
-:   -   When a user changes their displayname or avatar the server will now update all their join states to reflect this.
-    -   The server now adds \"age\" key to events to indicate how old they are. This is clock independent, so at no point does any server or webclient have to assume their clock is in sync with everyone else.
-    -   Fix bug where we didn\'t correctly pull in missing PDUs.
-    -   Fix bug where prev\_content key wasn\'t always returned.
-    -   Add support for password resets.
+-   When a user changes their displayname or avatar the server will now update all their join states to reflect this.
+-   The server now adds \"age\" key to events to indicate how old they are. This is clock independent, so at no point does any server or webclient have to assume their clock is in sync with everyone else.
+-   Fix bug where we didn\'t correctly pull in missing PDUs.
+-   Fix bug where prev\_content key wasn\'t always returned.
+-   Add support for password resets.
 
 Webclient:
 
-:   -   Improve page content loading.
-    -   Join/parts now trigger desktop notifications.
-    -   Always show room aliases in the UI if one is present.
-    -   No longer show user-count in the recents side panel.
-    -   Add up & down arrow support to the text box for message sending to step through your sent history.
-    -   Don\'t display notifications for our own messages.
-    -   Emotes are now formatted correctly in desktop notifications.
-    -   The recents list now differentiates between public & private rooms.
-    -   Fix bug where when switching between rooms the pagination flickered before the view jumped to the bottom of the screen.
-    -   Add bing word support.
+-   Improve page content loading.
+-   Join/parts now trigger desktop notifications.
+-   Always show room aliases in the UI if one is present.
+-   No longer show user-count in the recents side panel.
+-   Add up & down arrow support to the text box for message sending to step through your sent history.
+-   Don\'t display notifications for our own messages.
+-   Emotes are now formatted correctly in desktop notifications.
+-   The recents list now differentiates between public & private rooms.
+-   Fix bug where when switching between rooms the pagination flickered before the view jumped to the bottom of the screen.
+-   Add bing word support.
 
 Registration API:
 
-:   -   The registration API has been overhauled to function like the login API. In practice, this means registration requests must now include the following: \'type\':\'m.login.password\'. See UPGRADE for more information on this.
-    -   The \'user\_id\' key has been renamed to \'user\' to better match the login API.
-    -   There is an additional login type: \'m.login.email.identity\'.
-    -   The command client and web client have been updated to reflect these changes.
+-   The registration API has been overhauled to function like the login API. In practice, this means registration requests must now include the following: \'type\':\'m.login.password\'. See UPGRADE for more information on this.
+-   The \'user\_id\' key has been renamed to \'user\' to better match the login API.
+-   There is an additional login type: \'m.login.email.identity\'.
+-   The command client and web client have been updated to reflect these changes.
 
 Changes in synapse 0.2.3 (2014-09-12)
 =====================================
 
 Homeserver:
 
-:   -   Fix bug where we stopped sending events to remote home servers if a user from that home server left, even if there were some still in the room.
-    -   Fix bugs in the state conflict resolution where it was incorrectly rejecting events.
+-   Fix bug where we stopped sending events to remote home servers if a user from that home server left, even if there were some still in the room.
+-   Fix bugs in the state conflict resolution where it was incorrectly rejecting events.
 
 Webclient:
 
-:   -   Display room names and topics.
-    -   Allow setting/editing of room names and topics.
-    -   Display information about rooms on the main page.
-    -   Handle ban and kick events in real time.
-    -   VoIP UI and reliability improvements.
-    -   Add glare support for VoIP.
-    -   Improvements to initial startup speed.
-    -   Don\'t display duplicate join events.
-    -   Local echo of messages.
-    -   Differentiate sending and sent of local echo.
-    -   Various minor bug fixes.
+-   Display room names and topics.
+-   Allow setting/editing of room names and topics.
+-   Display information about rooms on the main page.
+-   Handle ban and kick events in real time.
+-   VoIP UI and reliability improvements.
+-   Add glare support for VoIP.
+-   Improvements to initial startup speed.
+-   Don\'t display duplicate join events.
+-   Local echo of messages.
+-   Differentiate sending and sent of local echo.
+-   Various minor bug fixes.
 
 Changes in synapse 0.2.2 (2014-09-06)
 =====================================
 
 Homeserver:
 
-:   -   When the server returns state events it now also includes the previous content.
-    -   Add support for inviting people when creating a new room.
-    -   Make the homeserver inform the room via m.room.aliases when a new alias is added for a room.
-    -   Validate m.room.power\_level events.
+-   When the server returns state events it now also includes the previous content.
+-   Add support for inviting people when creating a new room.
+-   Make the homeserver inform the room via m.room.aliases when a new alias is added for a room.
+-   Validate m.room.power\_level events.
 
 Webclient:
 
-:   -   Add support for captchas on registration.
-    -   Handle m.room.aliases events.
-    -   Asynchronously send messages and show a local echo.
-    -   Inform the UI when a message failed to send.
-    -   Only autoscroll on receiving a new message if the user was already at the bottom of the screen.
-    -   Add support for ban/kick reasons.
+-   Add support for captchas on registration.
+-   Handle m.room.aliases events.
+-   Asynchronously send messages and show a local echo.
+-   Inform the UI when a message failed to send.
+-   Only autoscroll on receiving a new message if the user was already at the bottom of the screen.
+-   Add support for ban/kick reasons.
 
 Changes in synapse 0.2.1 (2014-09-03)
 =====================================
 
 Homeserver:
 
-:   -   Added support for signing up with a third party id.
-    -   Add synctl scripts.
-    -   Added rate limiting.
-    -   Add option to change the external address the content repo uses.
-    -   Presence bug fixes.
+-   Added support for signing up with a third party id.
+-   Add synctl scripts.
+-   Added rate limiting.
+-   Add option to change the external address the content repo uses.
+-   Presence bug fixes.
 
 Webclient:
 
-:   -   Added support for signing up with a third party id.
-    -   Added support for banning and kicking users.
-    -   Added support for displaying and setting ops.
-    -   Added support for room names.
-    -   Fix bugs with room membership event display.
+-   Added support for signing up with a third party id.
+-   Added support for banning and kicking users.
+-   Added support for displaying and setting ops.
+-   Added support for room names.
+-   Fix bugs with room membership event display.
 
 Changes in synapse 0.2.0 (2014-09-02)
 =====================================
@@ -6323,36 +6732,36 @@ This update changes many configuration options, updates the database schema and
 
 Homeserver:
 
-:   -   Require SSL for server-server connections.
-    -   Add SSL listener for client-server connections.
-    -   Add ability to use config files.
-    -   Add support for kicking/banning and power levels.
-    -   Allow setting of room names and topics on creation.
-    -   Change presence to include last seen time of the user.
-    -   Change url path prefix to /\_matrix/\...
-    -   Bug fixes to presence.
+-   Require SSL for server-server connections.
+-   Add SSL listener for client-server connections.
+-   Add ability to use config files.
+-   Add support for kicking/banning and power levels.
+-   Allow setting of room names and topics on creation.
+-   Change presence to include last seen time of the user.
+-   Change url path prefix to /\_matrix/\...
+-   Bug fixes to presence.
 
 Webclient:
 
-:   -   Reskin the CSS for registration and login.
-    -   Various improvements to rooms CSS.
-    -   Support changes in client-server API.
-    -   Bug fixes to VOIP UI.
-    -   Various bug fixes to handling of changes to room member list.
+-   Reskin the CSS for registration and login.
+-   Various improvements to rooms CSS.
+-   Support changes in client-server API.
+-   Bug fixes to VOIP UI.
+-   Various bug fixes to handling of changes to room member list.
 
 Changes in synapse 0.1.2 (2014-08-29)
 =====================================
 
 Webclient:
 
-:   -   Add basic call state UI for VoIP calls.
+-   Add basic call state UI for VoIP calls.
 
 Changes in synapse 0.1.1 (2014-08-29)
 =====================================
 
 Homeserver:
 
-:   -   Fix bug that caused the event stream to not notify some clients about changes.
+-   Fix bug that caused the event stream to not notify some clients about changes.
 
 Changes in synapse 0.1.0 (2014-08-29)
 =====================================
@@ -6361,26 +6770,22 @@ Presence has been reenabled in this release.
 
 Homeserver:
 
-:   -
-
-        Update client to server API, including:
-
-        :   -   Use a more consistent url scheme.
-            -   Provide more useful information in the initial sync api.
-
-    -   Change the presence handling to be much more efficient.
-    -   Change the presence server to server API to not require explicit polling of all users who share a room with a user.
-    -   Fix races in the event streaming logic.
+-   Update client to server API, including:
+    -   Use a more consistent url scheme.
+    -   Provide more useful information in the initial sync api.
+-   Change the presence handling to be much more efficient.
+-   Change the presence server to server API to not require explicit polling of all users who share a room with a user.
+-   Fix races in the event streaming logic.
 
 Webclient:
 
-:   -   Update to use new client to server API.
-    -   Add basic VOIP support.
-    -   Add idle timers that change your status to away.
-    -   Add recent rooms column when viewing a room.
-    -   Various network efficiency improvements.
-    -   Add basic mobile browser support.
-    -   Add a settings page.
+-   Update to use new client to server API.
+-   Add basic VOIP support.
+-   Add idle timers that change your status to away.
+-   Add recent rooms column when viewing a room.
+-   Various network efficiency improvements.
+-   Add basic mobile browser support.
+-   Add a settings page.
 
 Changes in synapse 0.0.1 (2014-08-22)
 =====================================
@@ -6389,26 +6794,26 @@ Presence has been disabled in this release due to a bug that caused the homeserv
 
 Homeserver:
 
-:   -   Completely change the database schema to support generic event types.
-    -   Improve presence reliability.
-    -   Improve reliability of joining remote rooms.
-    -   Fix bug where room join events were duplicated.
-    -   Improve initial sync API to return more information to the client.
-    -   Stop generating fake messages for room membership events.
+-   Completely change the database schema to support generic event types.
+-   Improve presence reliability.
+-   Improve reliability of joining remote rooms.
+-   Fix bug where room join events were duplicated.
+-   Improve initial sync API to return more information to the client.
+-   Stop generating fake messages for room membership events.
 
 Webclient:
 
-:   -   Add tab completion of names.
-    -   Add ability to upload and send images.
-    -   Add profile pages.
-    -   Improve CSS layout of room.
-    -   Disambiguate identical display names.
-    -   Don\'t get remote users display names and avatars individually.
-    -   Use the new initial sync API to reduce number of round trips to the homeserver.
-    -   Change url scheme to use room aliases instead of room ids where known.
-    -   Increase longpoll timeout.
+-   Add tab completion of names.
+-   Add ability to upload and send images.
+-   Add profile pages.
+-   Improve CSS layout of room.
+-   Disambiguate identical display names.
+-   Don\'t get remote users display names and avatars individually.
+-   Use the new initial sync API to reduce number of round trips to the homeserver.
+-   Change url scheme to use room aliases instead of room ids where known.
+-   Increase longpoll timeout.
 
 Changes in synapse 0.0.0 (2014-08-13)
 =====================================
 
-> -   Initial alpha release
+-   Initial alpha release
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 524f82433d..1d7bb8f969 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -46,7 +46,7 @@ locally. You'll need python 3.6 or later, and to install a number of tools:
 
 ```
 # Install the dependencies
-pip install -e ".[lint]"
+pip install -e ".[lint,mypy]"
 
 # Run the linter script
 ./scripts-dev/lint.sh
@@ -63,6 +63,10 @@ run-time:
 ./scripts-dev/lint.sh path/to/file1.py path/to/file2.py path/to/folder
 ```
 
+You can also provide the `-d` option, which will lint the files that have been
+changed since the last git commit. This will often be significantly faster than
+linting the whole codebase.
+
 Before pushing new changes, ensure they don't produce linting errors. Commit any
 files that were corrected.
 
@@ -152,6 +156,24 @@ directory, you will need both a regular newsfragment *and* an entry in the
 debian changelog. (Though typically such changes should be submitted as two
 separate pull requests.)
 
+## Documentation
+
+There is a growing amount of documentation located in the [docs](docs)
+directory. This documentation is intended primarily for sysadmins running their
+own Synapse instance, as well as developers interacting externally with
+Synapse. [docs/dev](docs/dev) exists primarily to house documentation for
+Synapse developers. [docs/admin_api](docs/admin_api) houses documentation
+regarding Synapse's Admin API, which is used mostly by sysadmins and external
+service developers.
+
+New files added to both folders should be written in [Github-Flavoured
+Markdown](https://guides.github.com/features/mastering-markdown/), and attempts
+should be made to migrate existing documents to markdown where possible.
+
+Some documentation also exists in [Synapse's Github
+Wiki](https://github.com/matrix-org/synapse/wiki), although this is primarily
+contributed to by community authors.
+
 ## Sign off
 
 In order to have a concrete record that your contribution is intentional
diff --git a/INSTALL.md b/INSTALL.md
index 22f7b7c029..eaeb690092 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -57,7 +57,7 @@ light workloads.
 System requirements:
 
 - POSIX-compliant system (tested on Linux & OS X)
-- Python 3.5.2 or later, up to Python 3.8.
+- Python 3.5.2 or later, up to Python 3.9.
 - At least 1GB of free RAM if you want to join large public rooms like #matrix:matrix.org
 
 Synapse is written in Python but some of the libraries it uses are written in
@@ -487,7 +487,7 @@ In nginx this would be something like:
 ```
 location /.well-known/matrix/client {
     return 200 '{"m.homeserver": {"base_url": "https://<matrix.example.com>"}}';
-    add_header Content-Type application/json;
+    default_type application/json;
     add_header Access-Control-Allow-Origin *;
 }
 ```
diff --git a/README.rst b/README.rst
index 4a189c8bc4..d724cf97da 100644
--- a/README.rst
+++ b/README.rst
@@ -1,10 +1,6 @@
-================
-Synapse |shield|
-================
-
-.. |shield| image:: https://img.shields.io/matrix/synapse:matrix.org?label=support&logo=matrix
-  :alt: (get support on #synapse:matrix.org)
-  :target: https://matrix.to/#/#synapse:matrix.org
+=========================================================
+Synapse |support| |development| |license| |pypi| |python|
+=========================================================
 
 .. contents::
 
@@ -260,23 +256,27 @@ directory of your choice::
 Synapse has a number of external dependencies, that are easiest
 to install using pip and a virtualenv::
 
-    virtualenv -p python3 env
-    source env/bin/activate
-    python -m pip install --no-use-pep517 -e ".[all]"
+    python3 -m venv ./env
+    source ./env/bin/activate
+    pip install -e ".[all,test]"
 
 This will run a process of downloading and installing all the needed
-dependencies into a virtual env.
+dependencies into a virtual env. If any dependencies fail to install,
+try installing the failing modules individually::
 
-Once this is done, you may wish to run Synapse's unit tests, to
-check that everything is installed as it should be::
+    pip install -e "module-name"
+
+Once this is done, you may wish to run Synapse's unit tests to
+check that everything is installed correctly::
 
     python -m twisted.trial tests
 
-This should end with a 'PASSED' result::
+This should end with a 'PASSED' result (note that exact numbers will
+differ)::
 
-    Ran 143 tests in 0.601s
+    Ran 1337 tests in 716.064s
 
-    PASSED (successes=143)
+    PASSED (skips=15, successes=1322)
 
 Running the Integration Tests
 =============================
@@ -290,19 +290,6 @@ Testing with SyTest is recommended for verifying that changes related to the
 Client-Server API are functioning correctly. See the `installation instructions
 <https://github.com/matrix-org/sytest#installing>`_ for details.
 
-Building Internal API Documentation
-===================================
-
-Before building internal API documentation install sphinx and
-sphinxcontrib-napoleon::
-
-    pip install sphinx
-    pip install sphinxcontrib-napoleon
-
-Building internal API documentation::
-
-    python setup.py build_sphinx
-
 Troubleshooting
 ===============
 
@@ -387,3 +374,23 @@ something like the following in their logs::
 
 This is normally caused by a misconfiguration in your reverse-proxy. See
 `<docs/reverse_proxy.md>`_ and double-check that your settings are correct.
+
+.. |support| image:: https://img.shields.io/matrix/synapse:matrix.org?label=support&logo=matrix
+  :alt: (get support on #synapse:matrix.org)
+  :target: https://matrix.to/#/#synapse:matrix.org
+
+.. |development| image:: https://img.shields.io/matrix/synapse-dev:matrix.org?label=development&logo=matrix
+  :alt: (discuss development on #synapse-dev:matrix.org)
+  :target: https://matrix.to/#/#synapse-dev:matrix.org
+
+.. |license| image:: https://img.shields.io/github/license/matrix-org/synapse
+  :alt: (check license in LICENSE file)
+  :target: LICENSE
+
+.. |pypi| image:: https://img.shields.io/pypi/v/matrix-synapse
+  :alt: (latest version released on PyPi)
+  :target: https://pypi.org/project/matrix-synapse
+
+.. |python| image:: https://img.shields.io/pypi/pyversions/matrix-synapse
+  :alt: (supported python versions)
+  :target: https://pypi.org/project/matrix-synapse
diff --git a/UPGRADE.rst b/UPGRADE.rst
index 49e86e628f..6825b567e9 100644
--- a/UPGRADE.rst
+++ b/UPGRADE.rst
@@ -75,6 +75,91 @@ for example:
      wget https://packages.matrix.org/debian/pool/main/m/matrix-synapse-py3/matrix-synapse-py3_1.3.0+stretch1_amd64.deb
      dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
 
+Upgrading to v1.24.0
+====================
+
+Custom OpenID Connect mapping provider breaking change
+------------------------------------------------------
+
+This release allows the OpenID Connect mapping provider to perform normalisation
+of the localpart of the Matrix ID. This allows for the mapping provider to
+specify different algorithms, instead of the [default way](https://matrix.org/docs/spec/appendices#mapping-from-other-character-sets).
+
+If your Synapse configuration uses a custom mapping provider
+(`oidc_config.user_mapping_provider.module` is specified and not equal to
+`synapse.handlers.oidc_handler.JinjaOidcMappingProvider`) then you *must* ensure
+that `map_user_attributes` of the mapping provider performs some normalisation
+of the `localpart` returned. To match previous behaviour you can use the
+`map_username_to_mxid_localpart` function provided by Synapse. An example is
+shown below:
+
+.. code-block:: python
+
+  from synapse.types import map_username_to_mxid_localpart
+
+  class MyMappingProvider:
+      def map_user_attributes(self, userinfo, token):
+          # ... your custom logic ...
+          sso_user_id = ...
+          localpart = map_username_to_mxid_localpart(sso_user_id)
+
+          return {"localpart": localpart}
+
+Removal historical Synapse Admin API 
+------------------------------------
+
+Historically, the Synapse Admin API has been accessible under:
+
+* ``/_matrix/client/api/v1/admin``
+* ``/_matrix/client/unstable/admin``
+* ``/_matrix/client/r0/admin``
+* ``/_synapse/admin/v1``
+
+The endpoints with ``/_matrix/client/*`` prefixes have been removed as of v1.24.0.
+The Admin API is now only accessible under:
+
+* ``/_synapse/admin/v1``
+
+The only exception is the `/admin/whois` endpoint, which is
+`also available via the client-server API <https://matrix.org/docs/spec/client_server/r0.6.1#get-matrix-client-r0-admin-whois-userid>`_.
+
+The deprecation of the old endpoints was announced with Synapse 1.20.0 (released
+on 2020-09-22) and makes it easier for homeserver admins to lock down external
+access to the Admin API endpoints.
+
+Upgrading to v1.23.0
+====================
+
+Structured logging configuration breaking changes
+-------------------------------------------------
+
+This release deprecates use of the ``structured: true`` logging configuration for
+structured logging. If your logging configuration contains ``structured: true``
+then it should be modified based on the `structured logging documentation
+<https://github.com/matrix-org/synapse/blob/master/docs/structured_logging.md>`_.
+
+The ``structured`` and ``drains`` logging options are now deprecated and should
+be replaced by standard logging configuration of ``handlers`` and ``formatters``.
+
+A future will release of Synapse will make using ``structured: true`` an error.
+
+Upgrading to v1.22.0
+====================
+
+ThirdPartyEventRules breaking changes
+-------------------------------------
+
+This release introduces a backwards-incompatible change to modules making use of
+``ThirdPartyEventRules`` in Synapse. If you make use of a module defined under the
+``third_party_event_rules`` config option, please make sure it is updated to handle
+the below change:
+
+The ``http_client`` argument is no longer passed to modules as they are initialised. Instead,
+modules are expected to make use of the ``http_client`` property on the ``ModuleApi`` class.
+Modules are now passed a ``module_api`` argument during initialisation, which is an instance of
+``ModuleApi``. ``ModuleApi`` instances have a ``http_client`` property which acts the same as
+the ``http_client`` argument previously passed to ``ThirdPartyEventRules`` modules.
+
 Upgrading to v1.21.0
 ====================
 
diff --git a/changelog.d/8479.feature b/changelog.d/8479.feature
deleted file mode 100644
index 11adeec8a9..0000000000
--- a/changelog.d/8479.feature
+++ /dev/null
@@ -1 +0,0 @@
-Add the ability to send non-membership events into a room via the `ModuleApi`.
\ No newline at end of file
diff --git a/changelog.d/8527.bugfix b/changelog.d/8527.bugfix
deleted file mode 100644
index 727e0ba299..0000000000
--- a/changelog.d/8527.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix a bug introduced in v1.7.0 that could cause Synapse to insert values from non-state `m.room.retention` events into the `room_retention` database table.
diff --git a/changelog.d/8799.bugfix b/changelog.d/8799.bugfix
deleted file mode 100644
index a7e6b3556d..0000000000
--- a/changelog.d/8799.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Allow per-room profiles to be used for the server notice user.
diff --git a/changelog.d/8906.misc b/changelog.d/8906.misc
new file mode 100644
index 0000000000..8b95e4c553
--- /dev/null
+++ b/changelog.d/8906.misc
@@ -0,0 +1 @@
+Fix multiarch docker image builds.
diff --git a/contrib/grafana/README.md b/contrib/grafana/README.md
index ca780d412e..4608793394 100644
--- a/contrib/grafana/README.md
+++ b/contrib/grafana/README.md
@@ -3,4 +3,4 @@
 0. Set up Prometheus and Grafana. Out of scope for this readme. Useful documentation about using Grafana with Prometheus: http://docs.grafana.org/features/datasources/prometheus/
 1. Have your Prometheus scrape your Synapse. https://github.com/matrix-org/synapse/blob/master/docs/metrics-howto.md
 2. Import dashboard into Grafana. Download `synapse.json`. Import it to Grafana and select the correct Prometheus datasource. http://docs.grafana.org/reference/export_import/
-3. Set up additional recording rules
+3. Set up required recording rules. https://github.com/matrix-org/synapse/tree/master/contrib/prometheus
diff --git a/contrib/prometheus/README.md b/contrib/prometheus/README.md
index e646cb7ea7..b3f23bcc80 100644
--- a/contrib/prometheus/README.md
+++ b/contrib/prometheus/README.md
@@ -20,6 +20,7 @@ Add a new job to the main prometheus.conf file:
 ```
 
 ### for Prometheus v2
+
 Add a new job to the main prometheus.yml file:
 
 ```yaml
@@ -29,14 +30,17 @@ Add a new job to the main prometheus.yml file:
     scheme: "https"
 
     static_configs:
-    - targets: ['SERVER.LOCATION:PORT']
+    - targets: ["my.server.here:port"]
 ```
 
+An example of a Prometheus configuration with workers can be found in
+[metrics-howto.md](https://github.com/matrix-org/synapse/blob/master/docs/metrics-howto.md).
+
 To use `synapse.rules` add
 
 ```yaml
-    rule_files:
-      - "/PATH/TO/synapse-v2.rules"
+  rule_files:
+    - "/PATH/TO/synapse-v2.rules"
 ```
 
 Metrics are disabled by default when running synapse; they must be enabled
diff --git a/contrib/prometheus/consoles/synapse.html b/contrib/prometheus/consoles/synapse.html
index 69aa87f85e..cd9ad15231 100644
--- a/contrib/prometheus/consoles/synapse.html
+++ b/contrib/prometheus/consoles/synapse.html
@@ -9,7 +9,7 @@
 new PromConsole.Graph({
   node: document.querySelector("#process_resource_utime"),
   expr: "rate(process_cpu_seconds_total[2m]) * 100",
-  name: "[[job]]",  
+  name: "[[job]]-[[index]]",
   min: 0,
   max: 100,
   renderer: "line",
@@ -22,12 +22,12 @@ new PromConsole.Graph({
 </script>
 
 <h3>Memory</h3>
-<div id="process_resource_maxrss"></div>
+<div id="process_resident_memory_bytes"></div>
 <script>
 new PromConsole.Graph({
-  node: document.querySelector("#process_resource_maxrss"),
-  expr: "process_psutil_rss:max",
-  name: "Maxrss",
+  node: document.querySelector("#process_resident_memory_bytes"),
+  expr: "process_resident_memory_bytes",
+  name: "[[job]]-[[index]]",
   min: 0,
   renderer: "line",
   height: 150,
@@ -43,8 +43,8 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#process_fds"),
-  expr: "process_open_fds{job='synapse'}",
-  name: "FDs",
+  expr: "process_open_fds",
+  name: "[[job]]-[[index]]",
   min: 0,
   renderer: "line",
   height: 150,
@@ -62,8 +62,8 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#reactor_total_time"),
-  expr: "rate(python_twisted_reactor_tick_time:total[2m]) / 1000",
-  name: "time",
+  expr: "rate(python_twisted_reactor_tick_time_sum[2m])",
+  name: "[[job]]-[[index]]",
   max: 1,
   min: 0,
   renderer: "area",
@@ -80,8 +80,8 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#reactor_average_time"),
-  expr: "rate(python_twisted_reactor_tick_time:total[2m]) / rate(python_twisted_reactor_tick_time:count[2m]) / 1000",
-  name: "time",
+  expr: "rate(python_twisted_reactor_tick_time_sum[2m]) / rate(python_twisted_reactor_tick_time_count[2m])",
+  name: "[[job]]-[[index]]",
   min: 0,
   renderer: "line",
   height: 150,
@@ -97,14 +97,14 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#reactor_pending_calls"),
-  expr: "rate(python_twisted_reactor_pending_calls:total[30s])/rate(python_twisted_reactor_pending_calls:count[30s])",
-  name: "calls",
+  expr: "rate(python_twisted_reactor_pending_calls_sum[30s]) / rate(python_twisted_reactor_pending_calls_count[30s])",
+  name: "[[job]]-[[index]]",
   min: 0,
   renderer: "line",
   height: 150,
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
-  yTitle: "Pending Cals"
+  yTitle: "Pending Calls"
 })
 </script>
 
@@ -115,7 +115,7 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#synapse_storage_query_time"),
-  expr: "rate(synapse_storage_query_time:count[2m])",
+  expr: "sum(rate(synapse_storage_query_time_count[2m])) by (verb)",
   name: "[[verb]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
   yHoverFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
@@ -129,8 +129,8 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#synapse_storage_transaction_time"),
-  expr: "rate(synapse_storage_transaction_time:count[2m])",
-  name: "[[desc]]",
+  expr: "topk(10, rate(synapse_storage_transaction_time_count[2m]))",
+  name: "[[job]]-[[index]] [[desc]]",
   min: 0,
   yAxisFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
   yHoverFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
@@ -140,12 +140,12 @@ new PromConsole.Graph({
 </script>
 
 <h3>Transaction execution time</h3>
-<div id="synapse_storage_transactions_time_msec"></div>
+<div id="synapse_storage_transactions_time_sec"></div>
 <script>
 new PromConsole.Graph({
-  node: document.querySelector("#synapse_storage_transactions_time_msec"),
-  expr: "rate(synapse_storage_transaction_time:total[2m]) / 1000",
-  name: "[[desc]]",
+  node: document.querySelector("#synapse_storage_transactions_time_sec"),
+  expr: "rate(synapse_storage_transaction_time_sum[2m])",
+  name: "[[job]]-[[index]] [[desc]]",
   min: 0,
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
@@ -154,34 +154,33 @@ new PromConsole.Graph({
 })
 </script>
 
-<h3>Database scheduling latency</h3>
-<div id="synapse_storage_schedule_time"></div>
+<h3>Average time waiting for database connection</h3>
+<div id="synapse_storage_avg_waiting_time"></div>
 <script>
 new PromConsole.Graph({
-  node: document.querySelector("#synapse_storage_schedule_time"),
-  expr: "rate(synapse_storage_schedule_time:total[2m]) / 1000",
-  name: "Total latency",
+  node: document.querySelector("#synapse_storage_avg_waiting_time"),
+  expr: "rate(synapse_storage_schedule_time_sum[2m]) / rate(synapse_storage_schedule_time_count[2m])",
+  name: "[[job]]-[[index]]",
   min: 0,
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
-  yUnits: "s/s",
-  yTitle: "Usage"
+  yUnits: "s",
+  yTitle: "Time"
 })
 </script>
 
-<h3>Cache hit ratio</h3>
-<div id="synapse_cache_ratio"></div>
+<h3>Cache request rate</h3>
+<div id="synapse_cache_request_rate"></div>
 <script>
 new PromConsole.Graph({
-  node: document.querySelector("#synapse_cache_ratio"),
-  expr: "rate(synapse_util_caches_cache:total[2m]) * 100",
-  name: "[[name]]",
+  node: document.querySelector("#synapse_cache_request_rate"),
+  expr: "rate(synapse_util_caches_cache:total[2m])",
+  name: "[[job]]-[[index]] [[name]]",
   min: 0,
-  max: 100,
   yAxisFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
   yHoverFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
-  yUnits: "%",
-  yTitle: "Percentage"
+  yUnits: "rps",
+  yTitle: "Cache request rate"
 })
 </script>
 
@@ -191,7 +190,7 @@ new PromConsole.Graph({
 new PromConsole.Graph({
   node: document.querySelector("#synapse_cache_size"),
   expr: "synapse_util_caches_cache:size",
-  name: "[[name]]",
+  name: "[[job]]-[[index]] [[name]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
   yHoverFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
   yUnits: "",
@@ -206,8 +205,8 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#synapse_http_server_request_count_servlet"),
-  expr: "rate(synapse_http_server_request_count:servlet[2m])",
-  name: "[[servlet]]",
+  expr: "rate(synapse_http_server_in_flight_requests_count[2m])",
+  name: "[[job]]-[[index]] [[method]] [[servlet]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
   yUnits: "req/s",
@@ -219,8 +218,8 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#synapse_http_server_request_count_servlet_minus_events"),
-  expr: "rate(synapse_http_server_request_count:servlet{servlet!=\"EventStreamRestServlet\", servlet!=\"SyncRestServlet\"}[2m])",
-  name: "[[servlet]]",
+  expr: "rate(synapse_http_server_in_flight_requests_count{servlet!=\"EventStreamRestServlet\", servlet!=\"SyncRestServlet\"}[2m])",
+  name: "[[job]]-[[index]] [[method]] [[servlet]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
   yUnits: "req/s",
@@ -233,8 +232,8 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#synapse_http_server_response_time_avg"),
-  expr: "rate(synapse_http_server_response_time_seconds[2m]) / rate(synapse_http_server_response_count[2m]) / 1000",
-  name: "[[servlet]]",
+  expr: "rate(synapse_http_server_response_time_seconds_sum[2m]) / rate(synapse_http_server_response_count[2m])",
+  name: "[[job]]-[[index]] [[servlet]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
   yUnits: "s/req",
@@ -277,7 +276,7 @@ new PromConsole.Graph({
 new PromConsole.Graph({
   node: document.querySelector("#synapse_http_server_response_ru_utime"),
   expr: "rate(synapse_http_server_response_ru_utime_seconds[2m])",
-  name: "[[servlet]]",
+  name: "[[job]]-[[index]] [[servlet]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
   yUnits: "s/s",
@@ -292,7 +291,7 @@ new PromConsole.Graph({
 new PromConsole.Graph({
   node: document.querySelector("#synapse_http_server_response_db_txn_duration"),
   expr: "rate(synapse_http_server_response_db_txn_duration_seconds[2m])",
-  name: "[[servlet]]",
+  name: "[[job]]-[[index]] [[servlet]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
   yUnits: "s/s",
@@ -306,8 +305,8 @@ new PromConsole.Graph({
 <script>
 new PromConsole.Graph({
   node: document.querySelector("#synapse_http_server_send_time_avg"),
-  expr: "rate(synapse_http_server_response_time_second{servlet='RoomSendEventRestServlet'}[2m]) / rate(synapse_http_server_response_count{servlet='RoomSendEventRestServlet'}[2m]) / 1000",
-  name: "[[servlet]]",
+  expr: "rate(synapse_http_server_response_time_seconds_sum{servlet='RoomSendEventRestServlet'}[2m]) / rate(synapse_http_server_response_count{servlet='RoomSendEventRestServlet'}[2m])",
+  name: "[[job]]-[[index]] [[servlet]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
   yUnits: "s/req",
@@ -323,7 +322,7 @@ new PromConsole.Graph({
 new PromConsole.Graph({
   node: document.querySelector("#synapse_federation_client_sent"),
   expr: "rate(synapse_federation_client_sent[2m])",
-  name: "[[type]]",
+  name: "[[job]]-[[index]] [[type]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
   yUnits: "req/s",
@@ -337,7 +336,7 @@ new PromConsole.Graph({
 new PromConsole.Graph({
   node: document.querySelector("#synapse_federation_server_received"),
   expr: "rate(synapse_federation_server_received[2m])",
-  name: "[[type]]",
+  name: "[[job]]-[[index]] [[type]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
   yUnits: "req/s",
@@ -367,7 +366,7 @@ new PromConsole.Graph({
 new PromConsole.Graph({
   node: document.querySelector("#synapse_notifier_listeners"),
   expr: "synapse_notifier_listeners",
-  name: "listeners",
+  name: "[[job]]-[[index]]",
   min: 0,
   yAxisFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
   yHoverFormatter: PromConsole.NumberFormatter.humanizeNoSmallPrefix,
@@ -382,7 +381,7 @@ new PromConsole.Graph({
 new PromConsole.Graph({
   node: document.querySelector("#synapse_notifier_notified_events"),
   expr: "rate(synapse_notifier_notified_events[2m])",
-  name: "events",
+  name: "[[job]]-[[index]]",
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   yHoverFormatter: PromConsole.NumberFormatter.humanize,
   yUnits: "events/s",
diff --git a/debian/changelog b/debian/changelog
index 8d873a4845..6b819d201d 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,33 @@
+matrix-synapse-py3 (1.24.0) stable; urgency=medium
+
+  * New synapse release 1.24.0.
+
+ -- Synapse Packaging team <packages@matrix.org>  Wed, 09 Dec 2020 10:14:30 +0000
+
+matrix-synapse-py3 (1.23.1) stable; urgency=medium
+
+  * New synapse release 1.23.1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Wed, 09 Dec 2020 10:40:39 +0000
+
+matrix-synapse-py3 (1.23.0) stable; urgency=medium
+
+  * New synapse release 1.23.0.
+
+ -- Synapse Packaging team <packages@matrix.org>  Wed, 18 Nov 2020 11:41:28 +0000
+
+matrix-synapse-py3 (1.22.1) stable; urgency=medium
+
+  * New synapse release 1.22.1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Fri, 30 Oct 2020 15:25:37 +0000
+
+matrix-synapse-py3 (1.22.0) stable; urgency=medium
+
+  * New synapse release 1.22.0.
+
+ -- Synapse Packaging team <packages@matrix.org>  Tue, 27 Oct 2020 12:07:12 +0000
+
 matrix-synapse-py3 (1.21.2) stable; urgency=medium
 
   [ Synapse Packaging team ]
diff --git a/demo/start.sh b/demo/start.sh
index 83396e5c33..f6b5ea137f 100755
--- a/demo/start.sh
+++ b/demo/start.sh
@@ -30,6 +30,8 @@ for port in 8080 8081 8082; do
     if ! grep -F "Customisation made by demo/start.sh" -q  $DIR/etc/$port.config; then
         printf '\n\n# Customisation made by demo/start.sh\n' >> $DIR/etc/$port.config
 
+        echo "public_baseurl: http://localhost:$port/" >> $DIR/etc/$port.config
+
         echo 'enable_registration: true' >> $DIR/etc/$port.config
 
         # Warning, this heredoc depends on the interaction of tabs and spaces. Please don't
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 27512f8600..afd896ffc1 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -11,7 +11,7 @@
 #    docker build -f docker/Dockerfile --build-arg PYTHON_VERSION=3.6 .
 #
 
-ARG PYTHON_VERSION=3.7
+ARG PYTHON_VERSION=3.8
 
 ###
 ### Stage 0: builder
@@ -36,7 +36,8 @@ RUN pip install --prefix="/install" --no-warn-script-location \
         frozendict \
         jaeger-client \
         opentracing \
-        prometheus-client \
+        # Match the version constraints of Synapse
+        "prometheus_client>=0.4.0" \
         psycopg2 \
         pycparser \
         pyrsistent \
diff --git a/docker/README.md b/docker/README.md
index d0da34778e..c8f27b8566 100644
--- a/docker/README.md
+++ b/docker/README.md
@@ -83,7 +83,7 @@ docker logs synapse
 If all is well, you should now be able to connect to http://localhost:8008 and
 see a confirmation message.
 
-The following environment variables are supported in run mode:
+The following environment variables are supported in `run` mode:
 
 * `SYNAPSE_CONFIG_DIR`: where additional config files are stored. Defaults to
   `/data`.
@@ -94,6 +94,20 @@ The following environment variables are supported in run mode:
 * `UID`, `GID`: the user and group id to run Synapse as. Defaults to `991`, `991`.
 * `TZ`: the [timezone](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones) the container will run with. Defaults to `UTC`.
 
+For more complex setups (e.g. for workers) you can also pass your args directly to synapse using `run` mode. For example like this:
+
+```
+docker run -d --name synapse \
+    --mount type=volume,src=synapse-data,dst=/data \
+    -p 8008:8008 \
+    matrixdotorg/synapse:latest run \
+    -m synapse.app.generic_worker \
+    --config-path=/data/homeserver.yaml \
+    --config-path=/data/generic_worker.yaml
+```
+
+If you do not provide `-m`, the value of the `SYNAPSE_WORKER` environment variable is used. If you do not provide at least one `--config-path` or `-c`, the value of the `SYNAPSE_CONFIG_PATH` environment variable is used instead.
+
 ## Generating an (admin) user
 
 After synapse is running, you may wish to create a user via `register_new_matrix_user`.
diff --git a/docker/conf/homeserver.yaml b/docker/conf/homeserver.yaml
index c1110f0f53..a808485c12 100644
--- a/docker/conf/homeserver.yaml
+++ b/docker/conf/homeserver.yaml
@@ -90,7 +90,7 @@ federation_rc_concurrent: 3
 
 media_store_path: "/data/media"
 uploads_path: "/data/uploads"
-max_upload_size: "{{ SYNAPSE_MAX_UPLOAD_SIZE or "10M" }}"
+max_upload_size: "{{ SYNAPSE_MAX_UPLOAD_SIZE or "50M" }}"
 max_image_pixels: "32M"
 dynamic_thumbnails: false
 
diff --git a/docker/start.py b/docker/start.py
index 9f08134158..0d2c590b88 100755
--- a/docker/start.py
+++ b/docker/start.py
@@ -179,7 +179,7 @@ def run_generate_config(environ, ownership):
 
 
 def main(args, environ):
-    mode = args[1] if len(args) > 1 else None
+    mode = args[1] if len(args) > 1 else "run"
     desired_uid = int(environ.get("UID", "991"))
     desired_gid = int(environ.get("GID", "991"))
     synapse_worker = environ.get("SYNAPSE_WORKER", "synapse.app.homeserver")
@@ -205,36 +205,47 @@ def main(args, environ):
             config_dir, config_path, environ, ownership
         )
 
-    if mode is not None:
+    if mode != "run":
         error("Unknown execution mode '%s'" % (mode,))
 
-    config_dir = environ.get("SYNAPSE_CONFIG_DIR", "/data")
-    config_path = environ.get("SYNAPSE_CONFIG_PATH", config_dir + "/homeserver.yaml")
+    args = args[2:]
 
-    if not os.path.exists(config_path):
-        if "SYNAPSE_SERVER_NAME" in environ:
-            error(
-                """\
+    if "-m" not in args:
+        args = ["-m", synapse_worker] + args
+
+    # if there are no config files passed to synapse, try adding the default file
+    if not any(p.startswith("--config-path") or p.startswith("-c") for p in args):
+        config_dir = environ.get("SYNAPSE_CONFIG_DIR", "/data")
+        config_path = environ.get(
+            "SYNAPSE_CONFIG_PATH", config_dir + "/homeserver.yaml"
+        )
+
+        if not os.path.exists(config_path):
+            if "SYNAPSE_SERVER_NAME" in environ:
+                error(
+                    """\
 Config file '%s' does not exist.
 
 The synapse docker image no longer supports generating a config file on-the-fly
 based on environment variables. You can migrate to a static config file by
 running with 'migrate_config'. See the README for more details.
 """
+                    % (config_path,)
+                )
+
+            error(
+                "Config file '%s' does not exist. You should either create a new "
+                "config file by running with the `generate` argument (and then edit "
+                "the resulting file before restarting) or specify the path to an "
+                "existing config file with the SYNAPSE_CONFIG_PATH variable."
                 % (config_path,)
             )
 
-        error(
-            "Config file '%s' does not exist. You should either create a new "
-            "config file by running with the `generate` argument (and then edit "
-            "the resulting file before restarting) or specify the path to an "
-            "existing config file with the SYNAPSE_CONFIG_PATH variable."
-            % (config_path,)
-        )
+        args += ["--config-path", config_path]
 
-    log("Starting synapse with config file " + config_path)
+    log("Starting synapse with args " + " ".join(args))
 
-    args = ["python", "-m", synapse_worker, "--config-path", config_path]
+    args = ["python"] + args
     if ownership is not None:
         args = ["gosu", ownership] + args
         os.execv("/usr/sbin/gosu", args)
diff --git a/docs/admin_api/event_reports.md b/docs/admin_api/event_reports.md
new file mode 100644
index 0000000000..0159098138
--- /dev/null
+++ b/docs/admin_api/event_reports.md
@@ -0,0 +1,172 @@
+# Show reported events
+
+This API returns information about reported events.
+
+The api is:
+```
+GET /_synapse/admin/v1/event_reports?from=0&limit=10
+```
+To use it, you will need to authenticate by providing an `access_token` for a
+server admin: see [README.rst](README.rst).
+
+It returns a JSON body like the following:
+
+```json
+{
+    "event_reports": [
+        {
+            "event_id": "$bNUFCwGzWca1meCGkjp-zwslF-GfVcXukvRLI1_FaVY",
+            "id": 2,
+            "reason": "foo",
+            "score": -100,
+            "received_ts": 1570897107409,
+            "canonical_alias": "#alias1:matrix.org",
+            "room_id": "!ERAgBpSOcCCuTJqQPk:matrix.org",
+            "name": "Matrix HQ",
+            "sender": "@foobar:matrix.org",
+            "user_id": "@foo:matrix.org"
+        },
+        {
+            "event_id": "$3IcdZsDaN_En-S1DF4EMCy3v4gNRKeOJs8W5qTOKj4I",
+            "id": 3,
+            "reason": "bar",
+            "score": -100,
+            "received_ts": 1598889612059,
+            "canonical_alias": "#alias2:matrix.org",
+            "room_id": "!eGvUQuTCkHGVwNMOjv:matrix.org",
+            "name": "Your room name here",
+            "sender": "@foobar:matrix.org",
+            "user_id": "@bar:matrix.org"
+        }
+    ],
+    "next_token": 2,
+    "total": 4
+}
+```
+
+To paginate, check for `next_token` and if present, call the endpoint again with `from`
+set to the value of `next_token`. This will return a new page.
+
+If the endpoint does not return a `next_token` then there are no more reports to
+paginate through.
+
+**URL parameters:**
+
+* `limit`: integer - Is optional but is used for pagination, denoting the maximum number
+  of items to return in this call. Defaults to `100`.
+* `from`: integer - Is optional but used for pagination, denoting the offset in the
+  returned results. This should be treated as an opaque value and not explicitly set to
+  anything other than the return value of `next_token` from a previous call. Defaults to `0`.
+* `dir`: string - Direction of event report order. Whether to fetch the most recent
+  first (`b`) or the oldest first (`f`). Defaults to `b`.
+* `user_id`: string - Is optional and filters to only return users with user IDs that
+  contain this value. This is the user who reported the event and wrote the reason.
+* `room_id`: string - Is optional and filters to only return rooms with room IDs that
+  contain this value.
+
+**Response**
+
+The following fields are returned in the JSON response body:
+
+* `id`: integer - ID of event report.
+* `received_ts`: integer - The timestamp (in milliseconds since the unix epoch) when this
+  report was sent.
+* `room_id`: string - The ID of the room in which the event being reported is located.
+* `name`: string - The name of the room.
+* `event_id`: string - The ID of the reported event.
+* `user_id`: string - This is the user who reported the event and wrote the reason.
+* `reason`: string - Comment made by the `user_id` in this report. May be blank.
+* `score`: integer - Content is reported based upon a negative score, where -100 is
+  "most offensive" and 0 is "inoffensive".
+* `sender`: string - This is the ID of the user who sent the original message/event that
+  was reported.
+* `canonical_alias`: string - The canonical alias of the room. `null` if the room does not
+  have a canonical alias set.
+* `next_token`: integer - Indication for pagination. See above.
+* `total`: integer - Total number of event reports related to the query
+  (`user_id` and `room_id`).
+
+# Show details of a specific event report
+
+This API returns information about a specific event report.
+
+The api is:
+```
+GET /_synapse/admin/v1/event_reports/<report_id>
+```
+To use it, you will need to authenticate by providing an `access_token` for a
+server admin: see [README.rst](README.rst).
+
+It returns a JSON body like the following:
+
+```jsonc
+{
+    "event_id": "$bNUFCwGzWca1meCGkjp-zwslF-GfVcXukvRLI1_FaVY",
+    "event_json": {
+        "auth_events": [
+            "$YK4arsKKcc0LRoe700pS8DSjOvUT4NDv0HfInlMFw2M",
+            "$oggsNXxzPFRE3y53SUNd7nsj69-QzKv03a1RucHu-ws"
+        ],
+        "content": {
+            "body": "matrix.org: This Week in Matrix",
+            "format": "org.matrix.custom.html",
+            "formatted_body": "<strong>matrix.org</strong>:<br><a href=\"https://matrix.org/blog/\"><strong>This Week in Matrix</strong></a>",
+            "msgtype": "m.notice"
+        },
+        "depth": 546,
+        "hashes": {
+            "sha256": "xK1//xnmvHJIOvbgXlkI8eEqdvoMmihVDJ9J4SNlsAw"
+        },
+        "origin": "matrix.org",
+        "origin_server_ts": 1592291711430,
+        "prev_events": [
+            "$YK4arsKKcc0LRoe700pS8DSjOvUT4NDv0HfInlMFw2M"
+        ],
+        "prev_state": [],
+        "room_id": "!ERAgBpSOcCCuTJqQPk:matrix.org",
+        "sender": "@foobar:matrix.org",
+        "signatures": {
+            "matrix.org": {
+                "ed25519:a_JaEG": "cs+OUKW/iHx5pEidbWxh0UiNNHwe46Ai9LwNz+Ah16aWDNszVIe2gaAcVZfvNsBhakQTew51tlKmL2kspXk/Dg"
+            }
+        },
+        "type": "m.room.message",
+        "unsigned": {
+            "age_ts": 1592291711430,
+        }
+    },
+    "id": <report_id>,
+    "reason": "foo",
+    "score": -100,
+    "received_ts": 1570897107409,
+    "canonical_alias": "#alias1:matrix.org",
+    "room_id": "!ERAgBpSOcCCuTJqQPk:matrix.org",
+    "name": "Matrix HQ",
+    "sender": "@foobar:matrix.org",
+    "user_id": "@foo:matrix.org"
+}
+```
+
+**URL parameters:**
+
+* `report_id`: string - The ID of the event report.
+
+**Response**
+
+The following fields are returned in the JSON response body:
+
+* `id`: integer - ID of event report.
+* `received_ts`: integer - The timestamp (in milliseconds since the unix epoch) when this
+  report was sent.
+* `room_id`: string - The ID of the room in which the event being reported is located.
+* `name`: string - The name of the room.
+* `event_id`: string - The ID of the reported event.
+* `user_id`: string - This is the user who reported the event and wrote the reason.
+* `reason`: string - Comment made by the `user_id` in this report. May be blank.
+* `score`: integer - Content is reported based upon a negative score, where -100 is
+  "most offensive" and 0 is "inoffensive".
+* `sender`: string - This is the ID of the user who sent the original message/event that
+  was reported.
+* `canonical_alias`: string - The canonical alias of the room. `null` if the room does not
+  have a canonical alias set.
+* `event_json`: object - Details of the original event that was reported.
diff --git a/docs/admin_api/event_reports.rst b/docs/admin_api/event_reports.rst
deleted file mode 100644
index 461be01230..0000000000
--- a/docs/admin_api/event_reports.rst
+++ /dev/null
@@ -1,129 +0,0 @@
-Show reported events
-====================
-
-This API returns information about reported events.
-
-The api is::
-
-    GET /_synapse/admin/v1/event_reports?from=0&limit=10
-
-To use it, you will need to authenticate by providing an ``access_token`` for a
-server admin: see `README.rst <README.rst>`_.
-
-It returns a JSON body like the following:
-
-.. code:: jsonc
-
-    {
-        "event_reports": [
-            {
-                "content": {
-                    "reason": "foo",
-                    "score": -100
-                },
-                "event_id": "$bNUFCwGzWca1meCGkjp-zwslF-GfVcXukvRLI1_FaVY",
-                "event_json": {
-                    "auth_events": [
-                        "$YK4arsKKcc0LRoe700pS8DSjOvUT4NDv0HfInlMFw2M",
-                        "$oggsNXxzPFRE3y53SUNd7nsj69-QzKv03a1RucHu-ws"
-                    ],
-                    "content": {
-                        "body": "matrix.org: This Week in Matrix",
-                        "format": "org.matrix.custom.html",
-                        "formatted_body": "<strong>matrix.org</strong>:<br><a href=\"https://matrix.org/blog/\"><strong>This Week in Matrix</strong></a>",
-                        "msgtype": "m.notice"
-                    },
-                    "depth": 546,
-                    "hashes": {
-                        "sha256": "xK1//xnmvHJIOvbgXlkI8eEqdvoMmihVDJ9J4SNlsAw"
-                    },
-                    "origin": "matrix.org",
-                    "origin_server_ts": 1592291711430,
-                    "prev_events": [
-                        "$YK4arsKKcc0LRoe700pS8DSjOvUT4NDv0HfInlMFw2M"
-                    ],
-                    "prev_state": [],
-                    "room_id": "!ERAgBpSOcCCuTJqQPk:matrix.org",
-                    "sender": "@foobar:matrix.org",
-                    "signatures": {
-                        "matrix.org": {
-                            "ed25519:a_JaEG": "cs+OUKW/iHx5pEidbWxh0UiNNHwe46Ai9LwNz+Ah16aWDNszVIe2gaAcVZfvNsBhakQTew51tlKmL2kspXk/Dg"
-                        }
-                    },
-                    "type": "m.room.message",
-                    "unsigned": {
-                        "age_ts": 1592291711430,
-                    }
-                },
-                "id": 2,
-                "reason": "foo",
-                "received_ts": 1570897107409,
-                "room_alias": "#alias1:matrix.org",
-                "room_id": "!ERAgBpSOcCCuTJqQPk:matrix.org",
-                "sender": "@foobar:matrix.org",
-                "user_id": "@foo:matrix.org"
-            },
-            {
-                "content": {
-                    "reason": "bar",
-                    "score": -100
-                },
-                "event_id": "$3IcdZsDaN_En-S1DF4EMCy3v4gNRKeOJs8W5qTOKj4I",
-                "event_json": {
-                    // hidden items
-                    // see above
-                },
-                "id": 3,
-                "reason": "bar",
-                "received_ts": 1598889612059,
-                "room_alias": "#alias2:matrix.org",
-                "room_id": "!eGvUQuTCkHGVwNMOjv:matrix.org",
-                "sender": "@foobar:matrix.org",
-                "user_id": "@bar:matrix.org"
-            }
-        ],
-        "next_token": 2,
-        "total": 4
-    }
-
-To paginate, check for ``next_token`` and if present, call the endpoint again
-with ``from`` set to the value of ``next_token``. This will return a new page.
-
-If the endpoint does not return a ``next_token`` then there are no more
-reports to paginate through.
-
-**URL parameters:**
-
-- ``limit``: integer - Is optional but is used for pagination,
-  denoting the maximum number of items to return in this call. Defaults to ``100``.
-- ``from``: integer - Is optional but used for pagination,
-  denoting the offset in the returned results. This should be treated as an opaque value and
-  not explicitly set to anything other than the return value of ``next_token`` from a previous call.
-  Defaults to ``0``.
-- ``dir``: string - Direction of event report order. Whether to fetch the most recent first (``b``) or the
-  oldest first (``f``). Defaults to ``b``.
-- ``user_id``: string - Is optional and filters to only return users with user IDs that contain this value.
-  This is the user who reported the event and wrote the reason.
-- ``room_id``: string - Is optional and filters to only return rooms with room IDs that contain this value.
-
-**Response**
-
-The following fields are returned in the JSON response body:
-
-- ``id``: integer - ID of event report.
-- ``received_ts``: integer - The timestamp (in milliseconds since the unix epoch) when this report was sent.
-- ``room_id``: string - The ID of the room in which the event being reported is located.
-- ``event_id``: string - The ID of the reported event.
-- ``user_id``: string - This is the user who reported the event and wrote the reason.
-- ``reason``: string - Comment made by the ``user_id`` in this report. May be blank.
-- ``content``: object - Content of reported event.
-
-  - ``reason``: string - Comment made by the ``user_id`` in this report. May be blank.
-  - ``score``: integer - Content is reported based upon a negative score, where -100 is "most offensive" and 0 is "inoffensive".
-
-- ``sender``: string - This is the ID of the user who sent the original message/event that was reported.
-- ``room_alias``: string - The alias of the room. ``null`` if the room does not have a canonical alias set.
-- ``event_json``: object - Details of the original event that was reported.
-- ``next_token``: integer - Indication for pagination. See above.
-- ``total``: integer - Total number of event reports related to the query (``user_id`` and ``room_id``).
-
diff --git a/docs/admin_api/media_admin_api.md b/docs/admin_api/media_admin_api.md
index 26948770d8..71137c6dfc 100644
--- a/docs/admin_api/media_admin_api.md
+++ b/docs/admin_api/media_admin_api.md
@@ -1,6 +1,7 @@
 # List all media in a room
 
 This API gets a list of known media in a room.
+However, it only shows media from unencrypted events or rooms.
 
 The API is:
 ```
@@ -100,3 +101,82 @@ Response:
   "num_quarantined": 10  # The number of media items successfully quarantined
 }
 ```
+
+# Delete local media
+This API deletes the *local* media from the disk of your own server.
+This includes any local thumbnails and copies of media downloaded from
+remote homeservers.
+This API will not affect media that has been uploaded to external
+media repositories (e.g https://github.com/turt2live/matrix-media-repo/).
+See also [purge_remote_media.rst](purge_remote_media.rst).
+
+## Delete a specific local media
+Delete a specific `media_id`.
+
+Request:
+
+```
+DELETE /_synapse/admin/v1/media/<server_name>/<media_id>
+
+{}
+```
+
+URL Parameters
+
+* `server_name`: string - The name of your local server (e.g `matrix.org`)
+* `media_id`: string - The ID of the media (e.g `abcdefghijklmnopqrstuvwx`)
+
+Response:
+
+```json
+    {
+       "deleted_media": [
+          "abcdefghijklmnopqrstuvwx"
+       ],
+       "total": 1
+    }
+```
+
+The following fields are returned in the JSON response body:
+
+* `deleted_media`: an array of strings - List of deleted `media_id`
+* `total`: integer - Total number of deleted `media_id`
+
+## Delete local media by date or size
+
+Request:
+
+```
+POST /_synapse/admin/v1/media/<server_name>/delete?before_ts=<before_ts>
+
+{}
+```
+
+URL Parameters
+
+* `server_name`: string - The name of your local server (e.g `matrix.org`).
+* `before_ts`: string representing a positive integer - Unix timestamp in ms.
+Files that were last used before this timestamp will be deleted. It is the timestamp of
+last access and not the timestamp creation. 
+* `size_gt`: Optional - string representing a positive integer - Size of the media in bytes.
+Files that are larger will be deleted. Defaults to `0`.
+* `keep_profiles`: Optional - string representing a boolean - Switch to also delete files
+that are still used in image data (e.g user profile, room avatar).
+If `false` these files will be deleted. Defaults to `true`.
+
+Response:
+
+```json
+    {
+       "deleted_media": [
+          "abcdefghijklmnopqrstuvwx",
+          "abcdefghijklmnopqrstuvwz"
+       ],
+       "total": 2
+    }
+```
+
+The following fields are returned in the JSON response body:
+
+* `deleted_media`: an array of strings - List of deleted `media_id`
+* `total`: integer - Total number of deleted `media_id`
diff --git a/docs/admin_api/register_api.rst b/docs/admin_api/register_api.rst
index 3a63109aa0..c3057b204b 100644
--- a/docs/admin_api/register_api.rst
+++ b/docs/admin_api/register_api.rst
@@ -18,7 +18,8 @@ To fetch the nonce, you need to request one from the API::
 
 Once you have the nonce, you can make a ``POST`` to the same URL with a JSON
 body containing the nonce, username, password, whether they are an admin
-(optional, False by default), and a HMAC digest of the content.
+(optional, False by default), and a HMAC digest of the content. Also you can
+set the displayname (optional, ``username`` by default).
 
 As an example::
 
@@ -26,6 +27,7 @@ As an example::
   > {
      "nonce": "thisisanonce",
      "username": "pepper_roni",
+     "displayname": "Pepper Roni",
      "password": "pizza",
      "admin": true,
      "mac": "mac_digest_here"
diff --git a/docs/admin_api/rooms.md b/docs/admin_api/rooms.md
index fa9b914fa7..004a802e17 100644
--- a/docs/admin_api/rooms.md
+++ b/docs/admin_api/rooms.md
@@ -265,12 +265,10 @@ Response:
 Once the `next_token` parameter is no longer present, we know we've reached the
 end of the list.
 
-# DRAFT: Room Details API
+# Room Details API
 
 The Room Details admin API allows server admins to get all details of a room.
 
-This API is still a draft and details might change!
-
 The following fields are possible in the JSON response body:
 
 * `room_id` - The ID of the room.
@@ -384,7 +382,7 @@ the new room. Users on other servers will be unaffected.
 
 The API is:
 
-```json
+```
 POST /_synapse/admin/v1/rooms/<room_id>/delete
 ```
 
@@ -441,6 +439,10 @@ The following JSON body parameters are available:
             future attempts to join the room. Defaults to `false`.
 * `purge` - Optional. If set to `true`, it will remove all traces of the room from your database.
             Defaults to `true`.
+* `force_purge` - Optional, and ignored unless `purge` is `true`. If set to `true`, it
+  will force a purge to go ahead even if there are local users still in the room. Do not
+  use this unless a regular `purge` operation fails, as it could leave those users'
+  clients in a confused state.
 
 The JSON body must not be empty. The body must be at least `{}`.
 
diff --git a/docs/admin_api/statistics.md b/docs/admin_api/statistics.md
new file mode 100644
index 0000000000..d398a120fb
--- /dev/null
+++ b/docs/admin_api/statistics.md
@@ -0,0 +1,83 @@
+# Users' media usage statistics
+
+Returns information about all local media usage of users. Gives the
+possibility to filter them by time and user.
+
+The API is:
+
+```
+GET /_synapse/admin/v1/statistics/users/media
+```
+
+To use it, you will need to authenticate by providing an `access_token`
+for a server admin: see [README.rst](README.rst).
+
+A response body like the following is returned:
+
+```json
+{
+  "users": [
+    {
+      "displayname": "foo_user_0",
+      "media_count": 2,
+      "media_length": 134,
+      "user_id": "@foo_user_0:test"
+    },
+    {
+      "displayname": "foo_user_1",
+      "media_count": 2,
+      "media_length": 134,
+      "user_id": "@foo_user_1:test"
+    }
+  ],
+  "next_token": 3,
+  "total": 10
+}
+```
+
+To paginate, check for `next_token` and if present, call the endpoint
+again with `from` set to the value of `next_token`. This will return a new page.
+
+If the endpoint does not return a `next_token` then there are no more
+reports to paginate through.
+
+**Parameters**
+
+The following parameters should be set in the URL:
+
+* `limit`: string representing a positive integer - Is optional but is
+  used for pagination, denoting the maximum number of items to return
+  in this call. Defaults to `100`.
+* `from`: string representing a positive integer - Is optional but used for pagination,
+  denoting the offset in the returned results. This should be treated as an opaque value
+  and not explicitly set to anything other than the return value of `next_token` from a
+  previous call. Defaults to `0`.
+* `order_by` - string - The method in which to sort the returned list of users. Valid values are:
+  - `user_id` - Users are ordered alphabetically by `user_id`. This is the default.
+  - `displayname` - Users are ordered alphabetically by `displayname`.
+  - `media_length` - Users are ordered by the total size of uploaded media in bytes.
+    Smallest to largest.
+  - `media_count` - Users are ordered by number of uploaded media. Smallest to largest.
+* `from_ts` - string representing a positive integer - Considers only
+  files created at this timestamp or later. Unix timestamp in ms.
+* `until_ts` - string representing a positive integer - Considers only
+  files created at this timestamp or earlier. Unix timestamp in ms.
+* `search_term` - string - Filter users by their user ID localpart **or** displayname.
+  The search term can be found in any part of the string.
+  Defaults to no filtering.
+* `dir` - string - Direction of order. Either `f` for forwards or `b` for backwards.
+  Setting this value to `b` will reverse the above sort order. Defaults to `f`.
+
+
+**Response**
+
+The following fields are returned in the JSON response body:
+
+* `users` - An array of objects, each containing information
+  about the user and their local media. Objects contain the following fields:
+  - `displayname` - string - Displayname of this user.
+  - `media_count` - integer - Number of uploaded media by this user.
+  - `media_length` - integer - Size of uploaded media in bytes by this user.
+  - `user_id` - string - Fully-qualified user ID (ex. `@user:server.com`).
+* `next_token` - integer - Opaque value used for pagination. See above.
+* `total` - integer - Total number of users after filtering.
diff --git a/docs/admin_api/user_admin_api.rst b/docs/admin_api/user_admin_api.rst
index 7ca902faba..1473a3d4e3 100644
--- a/docs/admin_api/user_admin_api.rst
+++ b/docs/admin_api/user_admin_api.rst
@@ -176,6 +176,13 @@ The api is::
 
     GET /_synapse/admin/v1/whois/<user_id>
 
+and::
+
+    GET /_matrix/client/r0/admin/whois/<userId>
+
+See also: `Client Server API Whois
+<https://matrix.org/docs/spec/client_server/r0.6.1#get-matrix-client-r0-admin-whois-userid>`_
+
 To use it, you will need to authenticate by providing an ``access_token`` for a
 server admin: see `README.rst <README.rst>`_.
 
@@ -254,7 +261,7 @@ with a body of:
 
    {
        "new_password": "<secret>",
-       "logout_devices": true,
+       "logout_devices": true
    }
 
 To use it, you will need to authenticate by providing an ``access_token`` for a
@@ -341,6 +348,124 @@ The following fields are returned in the JSON response body:
 - ``total`` - Number of rooms.
 
 
+List media of an user
+================================
+Gets a list of all local media that a specific ``user_id`` has created.
+The response is ordered by creation date descending and media ID descending.
+The newest media is on top.
+
+The API is::
+
+  GET /_synapse/admin/v1/users/<user_id>/media
+
+To use it, you will need to authenticate by providing an ``access_token`` for a
+server admin: see `README.rst <README.rst>`_.
+
+A response body like the following is returned:
+
+.. code:: json
+
+    {
+      "media": [
+        {
+          "created_ts": 100400,
+          "last_access_ts": null,
+          "media_id": "qXhyRzulkwLsNHTbpHreuEgo",
+          "media_length": 67,
+          "media_type": "image/png",
+          "quarantined_by": null,
+          "safe_from_quarantine": false,
+          "upload_name": "test1.png"
+        },
+        {
+          "created_ts": 200400,
+          "last_access_ts": null,
+          "media_id": "FHfiSnzoINDatrXHQIXBtahw",
+          "media_length": 67,
+          "media_type": "image/png",
+          "quarantined_by": null,
+          "safe_from_quarantine": false,
+          "upload_name": "test2.png"
+        }
+      ],
+      "next_token": 3,
+      "total": 2
+    }
+
+To paginate, check for ``next_token`` and if present, call the endpoint again
+with ``from`` set to the value of ``next_token``. This will return a new page.
+
+If the endpoint does not return a ``next_token`` then there are no more
+reports to paginate through.
+
+**Parameters**
+
+The following parameters should be set in the URL:
+
+- ``user_id`` - string - fully qualified: for example, ``@user:server.com``.
+- ``limit``: string representing a positive integer - Is optional but is used for pagination,
+  denoting the maximum number of items to return in this call. Defaults to ``100``.
+- ``from``: string representing a positive integer - Is optional but used for pagination,
+  denoting the offset in the returned results. This should be treated as an opaque value and
+  not explicitly set to anything other than the return value of ``next_token`` from a previous call.
+  Defaults to ``0``.
+
+**Response**
+
+The following fields are returned in the JSON response body:
+
+- ``media`` - An array of objects, each containing information about a media.
+  Media objects contain the following fields:
+
+  - ``created_ts`` - integer - Timestamp when the content was uploaded in ms.
+  - ``last_access_ts`` - integer - Timestamp when the content was last accessed in ms.
+  - ``media_id`` - string - The id used to refer to the media.
+  - ``media_length`` - integer - Length of the media in bytes.
+  - ``media_type`` - string - The MIME-type of the media.
+  - ``quarantined_by`` - string - The user ID that initiated the quarantine request
+    for this media.
+
+  - ``safe_from_quarantine`` - bool - Status if this media is safe from quarantining.
+  - ``upload_name`` - string - The name the media was uploaded with.
+
+- ``next_token``: integer - Indication for pagination. See above.
+- ``total`` - integer - Total number of media.
+
+Login as a user
+===============
+
+Get an access token that can be used to authenticate as that user. Useful for
+when admins wish to do actions on behalf of a user.
+
+The API is::
+
+    POST /_synapse/admin/v1/users/<user_id>/login
+    {}
+
+An optional ``valid_until_ms`` field can be specified in the request body as an
+integer timestamp that specifies when the token should expire. By default tokens
+do not expire.
+
+A response body like the following is returned:
+
+.. code:: json
+
+    {
+        "access_token": "<opaque_access_token_string>"
+    }
+
+
+This API does *not* generate a new device for the user, and so will not appear
+their ``/devices`` list, and in general the target user should not be able to
+tell they have been logged in as.
+
+To expire the token call the standard ``/logout`` API with the token.
+
+Note: The token will expire if the *admin* user calls ``/logout/all`` from any
+of their devices, but the token will *not* expire if the target user does the
+same.
+
+
 User devices
 ============
 
@@ -375,7 +500,8 @@ A response body like the following is returned:
           "last_seen_ts": 1474491775025,
           "user_id": "<user_id>"
         }
-      ]
+      ],
+      "total": 2
     }
 
 **Parameters**
@@ -400,6 +526,8 @@ The following fields are returned in the JSON response body:
     devices was last seen. (May be a few minutes out of date, for efficiency reasons).
   - ``user_id`` - Owner of  device.
 
+- ``total`` - Total number of user's devices.
+
 Delete multiple devices
 ------------------
 Deletes the given devices for a specific ``user_id``, and invalidates
@@ -525,3 +653,82 @@ The following parameters should be set in the URL:
 
 - ``user_id`` - fully qualified: for example, ``@user:server.com``.
 - ``device_id`` - The device to delete.
+
+List all pushers
+================
+Gets information about all pushers for a specific ``user_id``.
+
+The API is::
+
+  GET /_synapse/admin/v1/users/<user_id>/pushers
+
+To use it, you will need to authenticate by providing an ``access_token`` for a
+server admin: see `README.rst <README.rst>`_.
+
+A response body like the following is returned:
+
+.. code:: json
+
+    {
+      "pushers": [
+        {
+          "app_display_name":"HTTP Push Notifications",
+          "app_id":"m.http",
+          "data": {
+            "url":"example.com"
+          },
+          "device_display_name":"pushy push",
+          "kind":"http",
+          "lang":"None",
+          "profile_tag":"",
+          "pushkey":"a@example.com"
+        }
+      ],
+      "total": 1
+    }
+
+**Parameters**
+
+The following parameters should be set in the URL:
+
+- ``user_id`` - fully qualified: for example, ``@user:server.com``.
+
+**Response**
+
+The following fields are returned in the JSON response body:
+
+- ``pushers`` - An array containing the current pushers for the user
+
+  - ``app_display_name`` - string - A string that will allow the user to identify
+    what application owns this pusher.
+
+  - ``app_id`` - string - This is a reverse-DNS style identifier for the application.
+    Max length, 64 chars.
+
+  - ``data`` - A dictionary of information for the pusher implementation itself.
+
+    - ``url`` - string - Required if ``kind`` is ``http``. The URL to use to send
+      notifications to.
+
+    - ``format`` - string - The format to use when sending notifications to the
+      Push Gateway.
+
+  - ``device_display_name`` - string -  A string that will allow the user to identify
+    what device owns this pusher.
+
+  - ``profile_tag`` - string - This string determines which set of device specific rules
+    this pusher executes.
+
+  - ``kind`` - string -  The kind of pusher. "http" is a pusher that sends HTTP pokes.
+  - ``lang`` - string - The preferred language for receiving notifications
+    (e.g. 'en' or 'en-US')
+
+  - ``profile_tag`` - string - This string determines which set of device specific rules
+    this pusher executes.
+
+  - ``pushkey`` - string - This is a unique identifier for this pusher.
+    Max length, 512 bytes.
+
+- ``total`` - integer - Number of pushers.
+
+See also `Client-Server API Spec <https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-pushers>`_
diff --git a/docs/code_style.md b/docs/code_style.md
index 6ef6f80290..f6c825d7d4 100644
--- a/docs/code_style.md
+++ b/docs/code_style.md
@@ -64,8 +64,6 @@ save as it takes a while and is very resource intensive.
     -   Use underscores for functions and variables.
 -   **Docstrings**: should follow the [google code
     style](https://google.github.io/styleguide/pyguide.html#38-comments-and-docstrings).
-    This is so that we can generate documentation with
-    [sphinx](http://sphinxcontrib-napoleon.readthedocs.org/en/latest/).
     See the
     [examples](http://sphinxcontrib-napoleon.readthedocs.io/en/latest/example_google.html)
     in the sphinx documentation.
diff --git a/docs/manhole.md b/docs/manhole.md
index 7375f5ad46..37d1d7823c 100644
--- a/docs/manhole.md
+++ b/docs/manhole.md
@@ -5,8 +5,45 @@ The "manhole" allows server administrators to access a Python shell on a running
 Synapse installation. This is a very powerful mechanism for administration and
 debugging.
 
+**_Security Warning_**
+
+Note that this will give administrative access to synapse to **all users** with
+shell access to the server. It should therefore **not** be enabled in
+environments where untrusted users have shell access.
+
+***
+
 To enable it, first uncomment the `manhole` listener configuration in
-`homeserver.yaml`:
+`homeserver.yaml`. The configuration is slightly different if you're using docker.
+
+#### Docker config
+
+If you are using Docker, set `bind_addresses` to `['0.0.0.0']` as shown:
+
+```yaml
+listeners:
+  - port: 9000
+    bind_addresses: ['0.0.0.0']
+    type: manhole
+```
+
+When using `docker run` to start the server, you will then need to change the command to the following to include the
+`manhole` port forwarding. The `-p 127.0.0.1:9000:9000` below is important: it 
+ensures that access to the `manhole` is only possible for local users.
+
+```bash
+docker run -d --name synapse \
+    --mount type=volume,src=synapse-data,dst=/data \
+    -p 8008:8008 \
+    -p 127.0.0.1:9000:9000 \
+    matrixdotorg/synapse:latest
+```
+
+#### Native config
+
+If you are not using docker, set `bind_addresses` to `['::1', '127.0.0.1']` as shown.
+The `bind_addresses` in the example below is important: it ensures that access to the
+`manhole` is only possible for local users).
 
 ```yaml
 listeners:
@@ -15,12 +52,7 @@ listeners:
     type: manhole
 ```
 
-(`bind_addresses` in the above is important: it ensures that access to the
-manhole is only possible for local users).
-
-Note that this will give administrative access to synapse to **all users** with
-shell access to the server. It should therefore **not** be enabled in
-environments where untrusted users have shell access.
+#### Accessing synapse manhole
 
 Then restart synapse, and point an ssh client at port 9000 on localhost, using
 the username `matrix`:
@@ -35,9 +67,12 @@ This gives a Python REPL in which `hs` gives access to the
 `synapse.server.HomeServer` object - which in turn gives access to many other
 parts of the process.
 
+Note that any call which returns a coroutine will need to be wrapped in `ensureDeferred`.
+
 As a simple example, retrieving an event from the database:
 
-```
->>> hs.get_datastore().get_event('$1416420717069yeQaw:matrix.org')
+```pycon
+>>> from twisted.internet import defer
+>>> defer.ensureDeferred(hs.get_datastore().get_event('$1416420717069yeQaw:matrix.org'))
 <Deferred at 0x7ff253fc6998 current result: <FrozenEvent event_id='$1416420717069yeQaw:matrix.org', type='m.room.create', state_key=''>>
 ```
diff --git a/docs/message_retention_policies.md b/docs/message_retention_policies.md
index 1dd60bdad9..75d2028e17 100644
--- a/docs/message_retention_policies.md
+++ b/docs/message_retention_policies.md
@@ -136,24 +136,34 @@ the server's database.
 
 ### Lifetime limits
 
-**Note: this feature is mainly useful within a closed federation or on
-servers that don't federate, because there currently is no way to
-enforce these limits in an open federation.**
-
-Server admins can restrict the values their local users are allowed to
-use for both `min_lifetime` and `max_lifetime`. These limits can be
-defined as such in the `retention` section of the configuration file:
+Server admins can set limits on the values of `max_lifetime` to use when
+purging old events in a room. These limits can be defined as such in the
+`retention` section of the configuration file:
 
 ```yaml
   allowed_lifetime_min: 1d
   allowed_lifetime_max: 1y
 ```
 
-Here, `allowed_lifetime_min` is the lowest value a local user can set
-for both `min_lifetime` and `max_lifetime`, and `allowed_lifetime_max`
-is the highest value. Both parameters are optional (e.g. setting
-`allowed_lifetime_min` but not `allowed_lifetime_max` only enforces a
-minimum and no maximum).
+The limits are considered when running purge jobs. If necessary, the
+effective value of `max_lifetime` will be brought between
+`allowed_lifetime_min` and `allowed_lifetime_max` (inclusive).
+This means that, if the value of `max_lifetime` defined in the room's state
+is lower than `allowed_lifetime_min`, the value of `allowed_lifetime_min`
+will be used instead. Likewise, if the value of `max_lifetime` is higher
+than `allowed_lifetime_max`, the value of `allowed_lifetime_max` will be
+used instead.
+
+In the example above, we ensure Synapse never deletes events that are less
+than one day old, and that it always deletes events that are over a year
+old.
+
+If a default policy is set, and its `max_lifetime` value is lower than
+`allowed_lifetime_min` or higher than `allowed_lifetime_max`, the same
+process applies.
+
+Both parameters are optional; if one is omitted Synapse won't use it to
+adjust the effective value of `max_lifetime`.
 
 Like other settings in this section, these parameters can be expressed
 either as a duration or as a number of milliseconds.
diff --git a/docs/metrics-howto.md b/docs/metrics-howto.md
index b386ec91c1..6b84153274 100644
--- a/docs/metrics-howto.md
+++ b/docs/metrics-howto.md
@@ -13,10 +13,12 @@
     can be enabled by adding the \"metrics\" resource to the existing
     listener as such:
 
-        resources:
-          - names:
-            - client
-            - metrics
+    ```yaml
+      resources:
+        - names:
+          - client
+          - metrics
+    ```
 
     This provides a simple way of adding metrics to your Synapse
     installation, and serves under `/_synapse/metrics`. If you do not
@@ -31,11 +33,13 @@
 
     Add a new listener to homeserver.yaml:
 
-        listeners:
-          - type: metrics
-            port: 9000
-            bind_addresses:
-              - '0.0.0.0'
+    ```yaml
+      listeners:
+        - type: metrics
+          port: 9000
+          bind_addresses:
+            - '0.0.0.0'
+    ```
 
     For both options, you will need to ensure that `enable_metrics` is
     set to `True`.
@@ -47,10 +51,13 @@
     It needs to set the `metrics_path` to a non-default value (under
     `scrape_configs`):
 
-        - job_name: "synapse"
-          metrics_path: "/_synapse/metrics"
-          static_configs:
-            - targets: ["my.server.here:port"]
+    ```yaml
+      - job_name: "synapse"
+        scrape_interval: 15s
+        metrics_path: "/_synapse/metrics"
+        static_configs:
+          - targets: ["my.server.here:port"]
+    ```
 
     where `my.server.here` is the IP address of Synapse, and `port` is
     the listener port configured with the `metrics` resource.
@@ -60,6 +67,9 @@
 
 1.  Restart Prometheus.
 
+1.  Consider using the [grafana dashboard](https://github.com/matrix-org/synapse/tree/master/contrib/grafana/)
+    and required [recording rules](https://github.com/matrix-org/synapse/tree/master/contrib/prometheus/) 
+
 ## Monitoring workers
 
 To monitor a Synapse installation using
@@ -74,9 +84,9 @@ To allow collecting metrics from a worker, you need to add a
 under `worker_listeners`:
 
 ```yaml
- - type: metrics
-   bind_address: ''
-   port: 9101
+  - type: metrics
+    bind_address: ''
+    port: 9101
 ```
 
 The `bind_address` and `port` parameters should be set so that
@@ -85,6 +95,38 @@ don't clash with an existing worker.
 With this example, the worker's metrics would then be available
 on `http://127.0.0.1:9101`.
 
+Example Prometheus target for Synapse with workers:
+
+```yaml
+  - job_name: "synapse"
+    scrape_interval: 15s
+    metrics_path: "/_synapse/metrics"
+    static_configs:
+      - targets: ["my.server.here:port"]
+        labels:
+          instance: "my.server"
+          job: "master"
+          index: 1
+      - targets: ["my.workerserver.here:port"]
+        labels:
+          instance: "my.server"
+          job: "generic_worker"
+          index: 1
+      - targets: ["my.workerserver.here:port"]
+        labels:
+          instance: "my.server"
+          job: "generic_worker"
+          index: 2
+      - targets: ["my.workerserver.here:port"]
+        labels:
+          instance: "my.server"
+          job: "media_repository"
+          index: 1
+```
+
+Labels (`instance`, `job`, `index`) can be defined as anything.
+The labels are used to group graphs in grafana.
+
 ## Renaming of metrics & deprecation of old names in 1.2
 
 Synapse 1.2 updates the Prometheus metrics to match the naming
diff --git a/docs/openid.md b/docs/openid.md
index 70b37f858b..da391f74aa 100644
--- a/docs/openid.md
+++ b/docs/openid.md
@@ -37,7 +37,7 @@ as follows:
    provided by `matrix.org` so no further action is needed.
 
  * If you installed Synapse into a virtualenv, run `/path/to/env/bin/pip
-   install synapse[oidc]` to install the necessary dependencies.
+   install matrix-synapse[oidc]` to install the necessary dependencies.
 
  * For other installation mechanisms, see the documentation provided by the
    maintainer.
@@ -52,14 +52,39 @@ specific providers.
 
 Here are a few configs for providers that should work with Synapse.
 
+### Microsoft Azure Active Directory
+Azure AD can act as an OpenID Connect Provider. Register a new application under 
+*App registrations* in the Azure AD management console. The RedirectURI for your
+application should point to your matrix server: `[synapse public baseurl]/_synapse/oidc/callback`
+
+Go to *Certificates & secrets* and register a new client secret. Make note of your 
+Directory (tenant) ID as it will be used in the Azure links.
+Edit your Synapse config file and change the `oidc_config` section:
+
+```yaml
+oidc_config:
+   enabled: true
+   issuer: "https://login.microsoftonline.com/<tenant id>/v2.0"
+   client_id: "<client id>"
+   client_secret: "<client secret>"
+   scopes: ["openid", "profile"]
+   authorization_endpoint: "https://login.microsoftonline.com/<tenant id>/oauth2/v2.0/authorize"
+   token_endpoint: "https://login.microsoftonline.com/<tenant id>/oauth2/v2.0/token"
+   userinfo_endpoint: "https://graph.microsoft.com/oidc/userinfo"
+
+   user_mapping_provider:
+     config:
+       localpart_template: "{{ user.preferred_username.split('@')[0] }}"
+       display_name_template: "{{ user.name }}"
+```
+
 ### [Dex][dex-idp]
 
 [Dex][dex-idp] is a simple, open-source, certified OpenID Connect Provider.
 Although it is designed to help building a full-blown provider with an
 external database, it can be configured with static passwords in a config file.
 
-Follow the [Getting Started
-guide](https://github.com/dexidp/dex/blob/master/Documentation/getting-started.md)
+Follow the [Getting Started guide](https://dexidp.io/docs/getting-started/)
 to install Dex.
 
 Edit `examples/config-dev.yaml` config file from the Dex repo to add a client:
@@ -73,7 +98,7 @@ staticClients:
   name: 'Synapse'
 ```
 
-Run with `dex serve examples/config-dex.yaml`.
+Run with `dex serve examples/config-dev.yaml`.
 
 Synapse config:
 
@@ -180,7 +205,7 @@ GitHub is a bit special as it is not an OpenID Connect compliant provider, but
 just a regular OAuth2 provider.
 
 The [`/user` API endpoint](https://developer.github.com/v3/users/#get-the-authenticated-user)
-can be used to retrieve information on the authenticated user. As the Synaspse
+can be used to retrieve information on the authenticated user. As the Synapse
 login mechanism needs an attribute to uniquely identify users, and that endpoint
 does not return a `sub` property, an alternative `subject_claim` has to be set.
 
@@ -238,13 +263,36 @@ Synapse config:
 
 ```yaml
 oidc_config:
-   enabled: true
-   issuer: "https://id.twitch.tv/oauth2/"
-   client_id: "your-client-id" # TO BE FILLED
-   client_secret: "your-client-secret" # TO BE FILLED
-   client_auth_method: "client_secret_post"
-   user_mapping_provider:
-     config:
-       localpart_template: '{{ user.preferred_username }}'
-       display_name_template: '{{ user.name }}'
+  enabled: true
+  issuer: "https://id.twitch.tv/oauth2/"
+  client_id: "your-client-id" # TO BE FILLED
+  client_secret: "your-client-secret" # TO BE FILLED
+  client_auth_method: "client_secret_post"
+  user_mapping_provider:
+    config:
+      localpart_template: "{{ user.preferred_username }}"
+      display_name_template: "{{ user.name }}"
+```
+
+### GitLab
+
+1. Create a [new application](https://gitlab.com/profile/applications).
+2. Add the `read_user` and `openid` scopes.
+3. Add this Callback URL: `[synapse public baseurl]/_synapse/oidc/callback`
+
+Synapse config:
+
+```yaml
+oidc_config:
+  enabled: true
+  issuer: "https://gitlab.com/"
+  client_id: "your-client-id" # TO BE FILLED
+  client_secret: "your-client-secret" # TO BE FILLED
+  client_auth_method: "client_secret_post"
+  scopes: ["openid", "read_user"]
+  user_profile_method: "userinfo_endpoint"
+  user_mapping_provider:
+    config:
+      localpart_template: '{{ user.nickname }}'
+      display_name_template: '{{ user.name }}'
 ```
diff --git a/docs/password_auth_providers.md b/docs/password_auth_providers.md
index 7d98d9f255..d2cdb9b2f4 100644
--- a/docs/password_auth_providers.md
+++ b/docs/password_auth_providers.md
@@ -26,6 +26,7 @@ Password auth provider classes must provide the following methods:
 
   It should perform any appropriate sanity checks on the provided
   configuration, and return an object which is then passed into
+  `__init__`.
 
   This method should have the `@staticmethod` decoration.
 
diff --git a/docs/reverse_proxy.md b/docs/reverse_proxy.md
index 46d8f35771..c7020f2df3 100644
--- a/docs/reverse_proxy.md
+++ b/docs/reverse_proxy.md
@@ -54,7 +54,7 @@ server {
         proxy_set_header X-Forwarded-For $remote_addr;
         # Nginx by default only allows file uploads up to 1M in size
         # Increase client_max_body_size to match max_upload_size defined in homeserver.yaml
-        client_max_body_size 10M;
+        client_max_body_size 50M;
     }
 }
 ```
diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml
index fccc32bd9f..c84a61e539 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -119,7 +119,7 @@ pid_file: DATADIR/homeserver.pid
 # For example, for room version 1, default_room_version should be set
 # to "1".
 #
-#default_room_version: "5"
+#default_room_version: "6"
 
 # The GC threshold parameters to pass to `gc.set_threshold`, if defined
 #
@@ -967,7 +967,7 @@ media_store_path: "DATADIR/media_store"
 
 # The largest allowed upload size in bytes
 #
-#max_upload_size: 10M
+#max_upload_size: 50M
 
 # The largest allowed size for a user avatar. If not defined, no
 # restriction will be imposed.
@@ -1317,8 +1317,9 @@ url_preview_accept_language:
 # email will be globally disabled.
 #
 # Additionally, if `msisdn` is not set, registration and password resets via msisdn
-# will be disabled regardless. This is due to Synapse currently not supporting any
-# method of sending SMS messages on its own.
+# will be disabled regardless, and users will not be able to associate an msisdn
+# identifier to their account. This is due to Synapse currently not supporting
+# any method of sending SMS messages on its own.
 #
 # To enable using an identity server for operations regarding a particular third-party
 # identifier type, set the value to the URL of that identity server as shown in the
@@ -1683,10 +1684,8 @@ trusted_key_servers:
 
 ## Single sign-on integration ##
 
-# Enable SAML2 for registration and login. Uses pysaml2.
-#
-# At least one of `sp_config` or `config_path` must be set in this section to
-# enable SAML login.
+# The following settings can be used to make Synapse use a single sign-on
+# provider for authentication, instead of its internal password database.
 #
 # You will probably also want to set the following options to `false` to
 # disable the regular login/registration flows:
@@ -1695,6 +1694,11 @@ trusted_key_servers:
 #
 # You will also want to investigate the settings under the "sso" configuration
 # section below.
+
+# Enable SAML2 for registration and login. Uses pysaml2.
+#
+# At least one of `sp_config` or `config_path` must be set in this section to
+# enable SAML login.
 #
 # Once SAML support is enabled, a metadata file will be exposed at
 # https://<server>:<port>/_matrix/saml2/metadata.xml, which you may be able to
@@ -1710,40 +1714,70 @@ saml2_config:
   # so it is not normally necessary to specify them unless you need to
   # override them.
   #
-  #sp_config:
-  #  # point this to the IdP's metadata. You can use either a local file or
-  #  # (preferably) a URL.
-  #  metadata:
-  #    #local: ["saml2/idp.xml"]
-  #    remote:
-  #      - url: https://our_idp/metadata.xml
-  #
-  #  # By default, the user has to go to our login page first. If you'd like
-  #  # to allow IdP-initiated login, set 'allow_unsolicited: true' in a
-  #  # 'service.sp' section:
-  #  #
-  #  #service:
-  #  #  sp:
-  #  #    allow_unsolicited: true
-  #
-  #  # The examples below are just used to generate our metadata xml, and you
-  #  # may well not need them, depending on your setup. Alternatively you
-  #  # may need a whole lot more detail - see the pysaml2 docs!
-  #
-  #  description: ["My awesome SP", "en"]
-  #  name: ["Test SP", "en"]
-  #
-  #  organization:
-  #    name: Example com
-  #    display_name:
-  #      - ["Example co", "en"]
-  #    url: "http://example.com"
-  #
-  #  contact_person:
-  #    - given_name: Bob
-  #      sur_name: "the Sysadmin"
-  #      email_address": ["admin@example.com"]
-  #      contact_type": technical
+  sp_config:
+    # Point this to the IdP's metadata. You must provide either a local
+    # file via the `local` attribute or (preferably) a URL via the
+    # `remote` attribute.
+    #
+    #metadata:
+    #  local: ["saml2/idp.xml"]
+    #  remote:
+    #    - url: https://our_idp/metadata.xml
+
+    # Allowed clock difference in seconds between the homeserver and IdP.
+    #
+    # Uncomment the below to increase the accepted time difference from 0 to 3 seconds.
+    #
+    #accepted_time_diff: 3
+
+    # By default, the user has to go to our login page first. If you'd like
+    # to allow IdP-initiated login, set 'allow_unsolicited: true' in a
+    # 'service.sp' section:
+    #
+    #service:
+    #  sp:
+    #    allow_unsolicited: true
+
+    # The examples below are just used to generate our metadata xml, and you
+    # may well not need them, depending on your setup. Alternatively you
+    # may need a whole lot more detail - see the pysaml2 docs!
+
+    #description: ["My awesome SP", "en"]
+    #name: ["Test SP", "en"]
+
+    #ui_info:
+    #  display_name:
+    #    - lang: en
+    #      text: "Display Name is the descriptive name of your service."
+    #  description:
+    #    - lang: en
+    #      text: "Description should be a short paragraph explaining the purpose of the service."
+    #  information_url:
+    #    - lang: en
+    #      text: "https://example.com/terms-of-service"
+    #  privacy_statement_url:
+    #    - lang: en
+    #      text: "https://example.com/privacy-policy"
+    #  keywords:
+    #    - lang: en
+    #      text: ["Matrix", "Element"]
+    #  logo:
+    #    - lang: en
+    #      text: "https://example.com/logo.svg"
+    #      width: "200"
+    #      height: "80"
+
+    #organization:
+    #  name: Example com
+    #  display_name:
+    #    - ["Example co", "en"]
+    #  url: "http://example.com"
+
+    #contact_person:
+    #  - given_name: Bob
+    #    sur_name: "the Sysadmin"
+    #    email_address": ["admin@example.com"]
+    #    contact_type": technical
 
   # Instead of putting the config inline as above, you can specify a
   # separate pysaml2 configuration file:
@@ -1818,12 +1852,19 @@ saml2_config:
   #  - attribute: department
   #    value: "sales"
 
+  # If the metadata XML contains multiple IdP entities then the `idp_entityid`
+  # option must be set to the entity to redirect users to.
+  #
+  # Most deployments only have a single IdP entity and so should omit this
+  # option.
+  #
+  #idp_entityid: 'https://our_idp/entityid'
 
-# OpenID Connect integration. The following settings can be used to make Synapse
-# use an OpenID Connect Provider for authentication, instead of its internal
-# password database.
+
+# Enable OpenID Connect (OIDC) / OAuth 2.0 for registration and login.
 #
-# See https://github.com/matrix-org/synapse/blob/master/docs/openid.md.
+# See https://github.com/matrix-org/synapse/blob/master/docs/openid.md
+# for some example configurations.
 #
 oidc_config:
   # Uncomment the following to enable authorization against an OpenID Connect
@@ -1892,6 +1933,14 @@ oidc_config:
   #
   #skip_verification: true
 
+  # Whether to fetch the user profile from the userinfo endpoint. Valid
+  # values are: "auto" or "userinfo_endpoint".
+  #
+  # Defaults to "auto", which fetches the userinfo endpoint if "openid" is included
+  # in `scopes`. Uncomment the following to always fetch the userinfo endpoint.
+  #
+  #user_profile_method: "userinfo_endpoint"
+
   # Uncomment to allow a user logging in via OIDC to match a pre-existing account instead
   # of failing. This could be used if switching from password logins to OIDC. Defaults to false.
   #
@@ -1948,15 +1997,37 @@ oidc_config:
 
 
 
-# Enable CAS for registration and login.
+# Enable Central Authentication Service (CAS) for registration and login.
 #
-#cas_config:
-#   enabled: true
-#   server_url: "https://cas-server.com"
-#   service_url: "https://homeserver.domain.com:8448"
-#   #displayname_attribute: name
-#   #required_attributes:
-#   #    name: value
+cas_config:
+  # Uncomment the following to enable authorization against a CAS server.
+  # Defaults to false.
+  #
+  #enabled: true
+
+  # The URL of the CAS authorization endpoint.
+  #
+  #server_url: "https://cas-server.com"
+
+  # The public URL of the homeserver.
+  #
+  #service_url: "https://homeserver.domain.com:8448"
+
+  # The attribute of the CAS response to use as the display name.
+  #
+  # If unset, no displayname will be set.
+  #
+  #displayname_attribute: name
+
+  # It is possible to configure Synapse to only allow logins if CAS attributes
+  # match particular values. All of the keys in the mapping below must exist
+  # and the values must match the given value. Alternately if the given value
+  # is None then any value is allowed (the attribute just must exist).
+  # All of the listed attributes must match for the login to be permitted.
+  #
+  #required_attributes:
+  #  userGroup: "staff"
+  #  department: None
 
 
 # Additional settings to use with single-sign on systems such as OpenID Connect,
@@ -2056,7 +2127,7 @@ sso:
 # and issued at ("iat") claims are validated if present.
 #
 # Note that this is a non-standard login type and client support is
-# expected to be non-existant.
+# expected to be non-existent.
 #
 # See https://github.com/matrix-org/synapse/blob/master/docs/jwt.md.
 #
@@ -2358,20 +2429,35 @@ password_providers:
 
 
 
-# Clients requesting push notifications can either have the body of
-# the message sent in the notification poke along with other details
-# like the sender, or just the event ID and room ID (`event_id_only`).
-# If clients choose the former, this option controls whether the
-# notification request includes the content of the event (other details
-# like the sender are still included). For `event_id_only` push, it
-# has no effect.
-#
-# For modern android devices the notification content will still appear
-# because it is loaded by the app. iPhone, however will send a
-# notification saying only that a message arrived and who it came from.
-#
-#push:
-#  include_content: true
+## Push ##
+
+push:
+  # Clients requesting push notifications can either have the body of
+  # the message sent in the notification poke along with other details
+  # like the sender, or just the event ID and room ID (`event_id_only`).
+  # If clients choose the former, this option controls whether the
+  # notification request includes the content of the event (other details
+  # like the sender are still included). For `event_id_only` push, it
+  # has no effect.
+  #
+  # For modern android devices the notification content will still appear
+  # because it is loaded by the app. iPhone, however will send a
+  # notification saying only that a message arrived and who it came from.
+  #
+  # The default value is "true" to include message details. Uncomment to only
+  # include the event ID and room ID in push notification payloads.
+  #
+  #include_content: false
+
+  # When a push notification is received, an unread count is also sent.
+  # This number can either be calculated as the number of unread messages
+  # for the user, or the number of *rooms* the user has unread messages in.
+  #
+  # The default value is "true", meaning push clients will see the number of
+  # rooms with unread messages in them. Uncomment to instead send the number
+  # of unread messages.
+  #
+  #group_unread_count_by_room: false
 
 
 # Spam checkers are third-party modules that can block specific actions
@@ -2577,7 +2663,7 @@ spam_checker:
 #
 # Options for the rules include:
 #
-#   user_id: Matches agaisnt the creator of the alias
+#   user_id: Matches against the creator of the alias
 #   room_id: Matches against the room ID being published
 #   alias: Matches against any current local or canonical aliases
 #            associated with the room
@@ -2623,7 +2709,7 @@ opentracing:
     # This is a list of regexes which are matched against the server_name of the
     # homeserver.
     #
-    # By defult, it is empty, so no servers are matched.
+    # By default, it is empty, so no servers are matched.
     #
     #homeserver_whitelist:
     #  - ".*"
@@ -2679,6 +2765,11 @@ opentracing:
 #  events: worker1
 #  typing: worker1
 
+# The worker that is used to run background tasks (e.g. cleaning up expired
+# data). If not provided this defaults to the main process.
+#
+#run_background_tasks_on: worker1
+
 
 # Configuration for Redis when using workers. This *must* be enabled when
 # using workers (unless using old style direct TCP configuration).
diff --git a/docs/sample_log_config.yaml b/docs/sample_log_config.yaml
index 55a48a9ed6..ff3c747180 100644
--- a/docs/sample_log_config.yaml
+++ b/docs/sample_log_config.yaml
@@ -3,7 +3,11 @@
 # This is a YAML file containing a standard Python logging configuration
 # dictionary. See [1] for details on the valid settings.
 #
+# Synapse also supports structured logging for machine readable logs which can
+# be ingested by ELK stacks. See [2] for details.
+#
 # [1]: https://docs.python.org/3.7/library/logging.config.html#configuration-dictionary-schema
+# [2]: https://github.com/matrix-org/synapse/blob/master/docs/structured_logging.md
 
 version: 1
 
@@ -59,7 +63,7 @@ root:
     # then write them to a file.
     #
     # Replace "buffer" with "console" to log to stderr instead. (Note that you'll
-    # also need to update the configuation for the `twisted` logger above, in
+    # also need to update the configuration for the `twisted` logger above, in
     # this case.)
     #
     handlers: [buffer]
diff --git a/docs/spam_checker.md b/docs/spam_checker.md
index eb10e115f9..7fc08f1b70 100644
--- a/docs/spam_checker.md
+++ b/docs/spam_checker.md
@@ -11,7 +11,7 @@ able to be imported by the running Synapse.
 The Python class is instantiated with two objects:
 
 * Any configuration (see below).
-* An instance of `synapse.spam_checker_api.SpamCheckerApi`.
+* An instance of `synapse.module_api.ModuleApi`.
 
 It then implements methods which return a boolean to alter behavior in Synapse.
 
@@ -26,11 +26,8 @@ well as some specific methods:
 The details of the each of these methods (as well as their inputs and outputs)
 are documented in the `synapse.events.spamcheck.SpamChecker` class.
 
-The `SpamCheckerApi` class provides a way for the custom spam checker class to
-call back into the homeserver internals. It currently implements the following
-methods:
-
-* `get_state_events_in_room`
+The `ModuleApi` class provides a way for the custom spam checker class to
+call back into the homeserver internals.
 
 ### Example
 
diff --git a/docs/sphinx/README.rst b/docs/sphinx/README.rst
deleted file mode 100644
index a7ab7c5500..0000000000
--- a/docs/sphinx/README.rst
+++ /dev/null
@@ -1 +0,0 @@
-TODO: how (if at all) is this actually maintained?
diff --git a/docs/sphinx/conf.py b/docs/sphinx/conf.py
deleted file mode 100644
index 5c5a115ca9..0000000000
--- a/docs/sphinx/conf.py
+++ /dev/null
@@ -1,271 +0,0 @@
-# -*- coding: utf-8 -*-
-#
-# Synapse documentation build configuration file, created by
-# sphinx-quickstart on Tue Jun 10 17:31:02 2014.
-#
-# This file is execfile()d with the current directory set to its
-# containing dir.
-#
-# Note that not all possible configuration values are present in this
-# autogenerated file.
-#
-# All configuration values have a default; values that are commented out
-# serve to show the default.
-
-import os
-import sys
-
-# If extensions (or modules to document with autodoc) are in another directory,
-# add these directories to sys.path here. If the directory is relative to the
-# documentation root, use os.path.abspath to make it absolute, like shown here.
-sys.path.insert(0, os.path.abspath(".."))
-
-# -- General configuration ------------------------------------------------
-
-# If your documentation needs a minimal Sphinx version, state it here.
-# needs_sphinx = '1.0'
-
-# Add any Sphinx extension module names here, as strings. They can be
-# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
-# ones.
-extensions = [
-    "sphinx.ext.autodoc",
-    "sphinx.ext.intersphinx",
-    "sphinx.ext.coverage",
-    "sphinx.ext.ifconfig",
-    "sphinxcontrib.napoleon",
-]
-
-# Add any paths that contain templates here, relative to this directory.
-templates_path = ["_templates"]
-
-# The suffix of source filenames.
-source_suffix = ".rst"
-
-# The encoding of source files.
-# source_encoding = 'utf-8-sig'
-
-# The master toctree document.
-master_doc = "index"
-
-# General information about the project.
-project = "Synapse"
-copyright = (
-    "Copyright 2014-2017 OpenMarket Ltd, 2017 Vector Creations Ltd, 2017 New Vector Ltd"
-)
-
-# The version info for the project you're documenting, acts as replacement for
-# |version| and |release|, also used in various other places throughout the
-# built documents.
-#
-# The short X.Y version.
-version = "1.0"
-# The full version, including alpha/beta/rc tags.
-release = "1.0"
-
-# The language for content autogenerated by Sphinx. Refer to documentation
-# for a list of supported languages.
-# language = None
-
-# There are two options for replacing |today|: either, you set today to some
-# non-false value, then it is used:
-# today = ''
-# Else, today_fmt is used as the format for a strftime call.
-# today_fmt = '%B %d, %Y'
-
-# List of patterns, relative to source directory, that match files and
-# directories to ignore when looking for source files.
-exclude_patterns = ["_build"]
-
-# The reST default role (used for this markup: `text`) to use for all
-# documents.
-# default_role = None
-
-# If true, '()' will be appended to :func: etc. cross-reference text.
-# add_function_parentheses = True
-
-# If true, the current module name will be prepended to all description
-# unit titles (such as .. function::).
-# add_module_names = True
-
-# If true, sectionauthor and moduleauthor directives will be shown in the
-# output. They are ignored by default.
-# show_authors = False
-
-# The name of the Pygments (syntax highlighting) style to use.
-pygments_style = "sphinx"
-
-# A list of ignored prefixes for module index sorting.
-# modindex_common_prefix = []
-
-# If true, keep warnings as "system message" paragraphs in the built documents.
-# keep_warnings = False
-
-
-# -- Options for HTML output ----------------------------------------------
-
-# The theme to use for HTML and HTML Help pages.  See the documentation for
-# a list of builtin themes.
-html_theme = "default"
-
-# Theme options are theme-specific and customize the look and feel of a theme
-# further.  For a list of options available for each theme, see the
-# documentation.
-# html_theme_options = {}
-
-# Add any paths that contain custom themes here, relative to this directory.
-# html_theme_path = []
-
-# The name for this set of Sphinx documents.  If None, it defaults to
-# "<project> v<release> documentation".
-# html_title = None
-
-# A shorter title for the navigation bar.  Default is the same as html_title.
-# html_short_title = None
-
-# The name of an image file (relative to this directory) to place at the top
-# of the sidebar.
-# html_logo = None
-
-# The name of an image file (within the static path) to use as favicon of the
-# docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
-# pixels large.
-# html_favicon = None
-
-# Add any paths that contain custom static files (such as style sheets) here,
-# relative to this directory. They are copied after the builtin static files,
-# so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ["_static"]
-
-# Add any extra paths that contain custom files (such as robots.txt or
-# .htaccess) here, relative to this directory. These files are copied
-# directly to the root of the documentation.
-# html_extra_path = []
-
-# If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
-# using the given strftime format.
-# html_last_updated_fmt = '%b %d, %Y'
-
-# If true, SmartyPants will be used to convert quotes and dashes to
-# typographically correct entities.
-# html_use_smartypants = True
-
-# Custom sidebar templates, maps document names to template names.
-# html_sidebars = {}
-
-# Additional templates that should be rendered to pages, maps page names to
-# template names.
-# html_additional_pages = {}
-
-# If false, no module index is generated.
-# html_domain_indices = True
-
-# If false, no index is generated.
-# html_use_index = True
-
-# If true, the index is split into individual pages for each letter.
-# html_split_index = False
-
-# If true, links to the reST sources are added to the pages.
-# html_show_sourcelink = True
-
-# If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
-# html_show_sphinx = True
-
-# If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
-# html_show_copyright = True
-
-# If true, an OpenSearch description file will be output, and all pages will
-# contain a <link> tag referring to it.  The value of this option must be the
-# base URL from which the finished HTML is served.
-# html_use_opensearch = ''
-
-# This is the file name suffix for HTML files (e.g. ".xhtml").
-# html_file_suffix = None
-
-# Output file base name for HTML help builder.
-htmlhelp_basename = "Synapsedoc"
-
-
-# -- Options for LaTeX output ---------------------------------------------
-
-latex_elements = {
-    # The paper size ('letterpaper' or 'a4paper').
-    # 'papersize': 'letterpaper',
-    # The font size ('10pt', '11pt' or '12pt').
-    # 'pointsize': '10pt',
-    # Additional stuff for the LaTeX preamble.
-    # 'preamble': '',
-}
-
-# Grouping the document tree into LaTeX files. List of tuples
-# (source start file, target name, title,
-#  author, documentclass [howto, manual, or own class]).
-latex_documents = [("index", "Synapse.tex", "Synapse Documentation", "TNG", "manual")]
-
-# The name of an image file (relative to this directory) to place at the top of
-# the title page.
-# latex_logo = None
-
-# For "manual" documents, if this is true, then toplevel headings are parts,
-# not chapters.
-# latex_use_parts = False
-
-# If true, show page references after internal links.
-# latex_show_pagerefs = False
-
-# If true, show URL addresses after external links.
-# latex_show_urls = False
-
-# Documents to append as an appendix to all manuals.
-# latex_appendices = []
-
-# If false, no module index is generated.
-# latex_domain_indices = True
-
-
-# -- Options for manual page output ---------------------------------------
-
-# One entry per manual page. List of tuples
-# (source start file, name, description, authors, manual section).
-man_pages = [("index", "synapse", "Synapse Documentation", ["TNG"], 1)]
-
-# If true, show URL addresses after external links.
-# man_show_urls = False
-
-
-# -- Options for Texinfo output -------------------------------------------
-
-# Grouping the document tree into Texinfo files. List of tuples
-# (source start file, target name, title, author,
-#  dir menu entry, description, category)
-texinfo_documents = [
-    (
-        "index",
-        "Synapse",
-        "Synapse Documentation",
-        "TNG",
-        "Synapse",
-        "One line description of project.",
-        "Miscellaneous",
-    )
-]
-
-# Documents to append as an appendix to all manuals.
-# texinfo_appendices = []
-
-# If false, no module index is generated.
-# texinfo_domain_indices = True
-
-# How to display URL addresses: 'footnote', 'no', or 'inline'.
-# texinfo_show_urls = 'footnote'
-
-# If true, do not generate a @detailmenu in the "Top" node's menu.
-# texinfo_no_detailmenu = False
-
-
-# Example configuration for intersphinx: refer to the Python standard library.
-intersphinx_mapping = {"http://docs.python.org/": None}
-
-napoleon_include_special_with_doc = True
-napoleon_use_ivar = True
diff --git a/docs/sphinx/index.rst b/docs/sphinx/index.rst
deleted file mode 100644
index 76a4c0c7bf..0000000000
--- a/docs/sphinx/index.rst
+++ /dev/null
@@ -1,20 +0,0 @@
-.. Synapse documentation master file, created by
-   sphinx-quickstart on Tue Jun 10 17:31:02 2014.
-   You can adapt this file completely to your liking, but it should at least
-   contain the root `toctree` directive.
-
-Welcome to Synapse's documentation!
-===================================
-
-Contents:
-
-.. toctree::
-   synapse
-
-Indices and tables
-==================
-
-* :ref:`genindex`
-* :ref:`modindex`
-* :ref:`search`
-
diff --git a/docs/sphinx/modules.rst b/docs/sphinx/modules.rst
deleted file mode 100644
index 1c7f70bd13..0000000000
--- a/docs/sphinx/modules.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse
-=======
-
-.. toctree::
-   :maxdepth: 4
-
-   synapse
diff --git a/docs/sphinx/synapse.api.auth.rst b/docs/sphinx/synapse.api.auth.rst
deleted file mode 100644
index 931eb59836..0000000000
--- a/docs/sphinx/synapse.api.auth.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.auth module
-=======================
-
-.. automodule:: synapse.api.auth
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.constants.rst b/docs/sphinx/synapse.api.constants.rst
deleted file mode 100644
index a1e3c47f68..0000000000
--- a/docs/sphinx/synapse.api.constants.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.constants module
-============================
-
-.. automodule:: synapse.api.constants
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.dbobjects.rst b/docs/sphinx/synapse.api.dbobjects.rst
deleted file mode 100644
index e9d31167e0..0000000000
--- a/docs/sphinx/synapse.api.dbobjects.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.dbobjects module
-============================
-
-.. automodule:: synapse.api.dbobjects
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.errors.rst b/docs/sphinx/synapse.api.errors.rst
deleted file mode 100644
index f1c6881478..0000000000
--- a/docs/sphinx/synapse.api.errors.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.errors module
-=========================
-
-.. automodule:: synapse.api.errors
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.event_stream.rst b/docs/sphinx/synapse.api.event_stream.rst
deleted file mode 100644
index 9291cb2dbc..0000000000
--- a/docs/sphinx/synapse.api.event_stream.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.event_stream module
-===============================
-
-.. automodule:: synapse.api.event_stream
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.events.factory.rst b/docs/sphinx/synapse.api.events.factory.rst
deleted file mode 100644
index 2e71ff6070..0000000000
--- a/docs/sphinx/synapse.api.events.factory.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.events.factory module
-=================================
-
-.. automodule:: synapse.api.events.factory
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.events.room.rst b/docs/sphinx/synapse.api.events.room.rst
deleted file mode 100644
index 6cd5998599..0000000000
--- a/docs/sphinx/synapse.api.events.room.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.events.room module
-==============================
-
-.. automodule:: synapse.api.events.room
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.events.rst b/docs/sphinx/synapse.api.events.rst
deleted file mode 100644
index b762da55ee..0000000000
--- a/docs/sphinx/synapse.api.events.rst
+++ /dev/null
@@ -1,18 +0,0 @@
-synapse.api.events package
-==========================
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.api.events.factory
-   synapse.api.events.room
-
-Module contents
----------------
-
-.. automodule:: synapse.api.events
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.handlers.events.rst b/docs/sphinx/synapse.api.handlers.events.rst
deleted file mode 100644
index d2e1b54ac0..0000000000
--- a/docs/sphinx/synapse.api.handlers.events.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.handlers.events module
-==================================
-
-.. automodule:: synapse.api.handlers.events
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.handlers.factory.rst b/docs/sphinx/synapse.api.handlers.factory.rst
deleted file mode 100644
index b04a93f740..0000000000
--- a/docs/sphinx/synapse.api.handlers.factory.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.handlers.factory module
-===================================
-
-.. automodule:: synapse.api.handlers.factory
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.handlers.federation.rst b/docs/sphinx/synapse.api.handlers.federation.rst
deleted file mode 100644
index 61a6542210..0000000000
--- a/docs/sphinx/synapse.api.handlers.federation.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.handlers.federation module
-======================================
-
-.. automodule:: synapse.api.handlers.federation
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.handlers.register.rst b/docs/sphinx/synapse.api.handlers.register.rst
deleted file mode 100644
index 388f144eca..0000000000
--- a/docs/sphinx/synapse.api.handlers.register.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.handlers.register module
-====================================
-
-.. automodule:: synapse.api.handlers.register
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.handlers.room.rst b/docs/sphinx/synapse.api.handlers.room.rst
deleted file mode 100644
index 8ca156c7ff..0000000000
--- a/docs/sphinx/synapse.api.handlers.room.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.handlers.room module
-================================
-
-.. automodule:: synapse.api.handlers.room
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.handlers.rst b/docs/sphinx/synapse.api.handlers.rst
deleted file mode 100644
index e84f563fcb..0000000000
--- a/docs/sphinx/synapse.api.handlers.rst
+++ /dev/null
@@ -1,21 +0,0 @@
-synapse.api.handlers package
-============================
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.api.handlers.events
-   synapse.api.handlers.factory
-   synapse.api.handlers.federation
-   synapse.api.handlers.register
-   synapse.api.handlers.room
-
-Module contents
----------------
-
-.. automodule:: synapse.api.handlers
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.notifier.rst b/docs/sphinx/synapse.api.notifier.rst
deleted file mode 100644
index 631b42a497..0000000000
--- a/docs/sphinx/synapse.api.notifier.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.notifier module
-===========================
-
-.. automodule:: synapse.api.notifier
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.register_events.rst b/docs/sphinx/synapse.api.register_events.rst
deleted file mode 100644
index 79ad4ce211..0000000000
--- a/docs/sphinx/synapse.api.register_events.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.register_events module
-==================================
-
-.. automodule:: synapse.api.register_events
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.room_events.rst b/docs/sphinx/synapse.api.room_events.rst
deleted file mode 100644
index bead1711f5..0000000000
--- a/docs/sphinx/synapse.api.room_events.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.room_events module
-==============================
-
-.. automodule:: synapse.api.room_events
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.rst b/docs/sphinx/synapse.api.rst
deleted file mode 100644
index f4d39ff331..0000000000
--- a/docs/sphinx/synapse.api.rst
+++ /dev/null
@@ -1,30 +0,0 @@
-synapse.api package
-===================
-
-Subpackages
------------
-
-.. toctree::
-
-    synapse.api.events
-    synapse.api.handlers
-    synapse.api.streams
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.api.auth
-   synapse.api.constants
-   synapse.api.errors
-   synapse.api.notifier
-   synapse.api.storage
-
-Module contents
----------------
-
-.. automodule:: synapse.api
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.server.rst b/docs/sphinx/synapse.api.server.rst
deleted file mode 100644
index b01600235e..0000000000
--- a/docs/sphinx/synapse.api.server.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.server module
-=========================
-
-.. automodule:: synapse.api.server
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.storage.rst b/docs/sphinx/synapse.api.storage.rst
deleted file mode 100644
index afa40685c4..0000000000
--- a/docs/sphinx/synapse.api.storage.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.storage module
-==========================
-
-.. automodule:: synapse.api.storage
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.stream.rst b/docs/sphinx/synapse.api.stream.rst
deleted file mode 100644
index 0d5e3f01bf..0000000000
--- a/docs/sphinx/synapse.api.stream.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.stream module
-=========================
-
-.. automodule:: synapse.api.stream
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.streams.event.rst b/docs/sphinx/synapse.api.streams.event.rst
deleted file mode 100644
index 2ac45a35c8..0000000000
--- a/docs/sphinx/synapse.api.streams.event.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.api.streams.event module
-================================
-
-.. automodule:: synapse.api.streams.event
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.api.streams.rst b/docs/sphinx/synapse.api.streams.rst
deleted file mode 100644
index 72eb205caf..0000000000
--- a/docs/sphinx/synapse.api.streams.rst
+++ /dev/null
@@ -1,17 +0,0 @@
-synapse.api.streams package
-===========================
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.api.streams.event
-
-Module contents
----------------
-
-.. automodule:: synapse.api.streams
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.app.homeserver.rst b/docs/sphinx/synapse.app.homeserver.rst
deleted file mode 100644
index 54b93da8fe..0000000000
--- a/docs/sphinx/synapse.app.homeserver.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.app.homeserver module
-=============================
-
-.. automodule:: synapse.app.homeserver
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.app.rst b/docs/sphinx/synapse.app.rst
deleted file mode 100644
index 4535b79827..0000000000
--- a/docs/sphinx/synapse.app.rst
+++ /dev/null
@@ -1,17 +0,0 @@
-synapse.app package
-===================
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.app.homeserver
-
-Module contents
----------------
-
-.. automodule:: synapse.app
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.db.rst b/docs/sphinx/synapse.db.rst
deleted file mode 100644
index 83df6c03db..0000000000
--- a/docs/sphinx/synapse.db.rst
+++ /dev/null
@@ -1,10 +0,0 @@
-synapse.db package
-==================
-
-Module contents
----------------
-
-.. automodule:: synapse.db
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.federation.handler.rst b/docs/sphinx/synapse.federation.handler.rst
deleted file mode 100644
index 5597f5c46d..0000000000
--- a/docs/sphinx/synapse.federation.handler.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.federation.handler module
-=================================
-
-.. automodule:: synapse.federation.handler
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.federation.messaging.rst b/docs/sphinx/synapse.federation.messaging.rst
deleted file mode 100644
index 4bbaabf3ef..0000000000
--- a/docs/sphinx/synapse.federation.messaging.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.federation.messaging module
-===================================
-
-.. automodule:: synapse.federation.messaging
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.federation.pdu_codec.rst b/docs/sphinx/synapse.federation.pdu_codec.rst
deleted file mode 100644
index 8f0b15a63c..0000000000
--- a/docs/sphinx/synapse.federation.pdu_codec.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.federation.pdu_codec module
-===================================
-
-.. automodule:: synapse.federation.pdu_codec
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.federation.persistence.rst b/docs/sphinx/synapse.federation.persistence.rst
deleted file mode 100644
index db7ab8ade1..0000000000
--- a/docs/sphinx/synapse.federation.persistence.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.federation.persistence module
-=====================================
-
-.. automodule:: synapse.federation.persistence
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.federation.replication.rst b/docs/sphinx/synapse.federation.replication.rst
deleted file mode 100644
index 49e26e0928..0000000000
--- a/docs/sphinx/synapse.federation.replication.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.federation.replication module
-=====================================
-
-.. automodule:: synapse.federation.replication
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.federation.rst b/docs/sphinx/synapse.federation.rst
deleted file mode 100644
index 7240c7901b..0000000000
--- a/docs/sphinx/synapse.federation.rst
+++ /dev/null
@@ -1,22 +0,0 @@
-synapse.federation package
-==========================
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.federation.handler
-   synapse.federation.pdu_codec
-   synapse.federation.persistence
-   synapse.federation.replication
-   synapse.federation.transport
-   synapse.federation.units
-
-Module contents
----------------
-
-.. automodule:: synapse.federation
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.federation.transport.rst b/docs/sphinx/synapse.federation.transport.rst
deleted file mode 100644
index 877956b3c9..0000000000
--- a/docs/sphinx/synapse.federation.transport.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.federation.transport module
-===================================
-
-.. automodule:: synapse.federation.transport
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.federation.units.rst b/docs/sphinx/synapse.federation.units.rst
deleted file mode 100644
index 8f9212b07d..0000000000
--- a/docs/sphinx/synapse.federation.units.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.federation.units module
-===============================
-
-.. automodule:: synapse.federation.units
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.persistence.rst b/docs/sphinx/synapse.persistence.rst
deleted file mode 100644
index 37c0c23720..0000000000
--- a/docs/sphinx/synapse.persistence.rst
+++ /dev/null
@@ -1,19 +0,0 @@
-synapse.persistence package
-===========================
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.persistence.service
-   synapse.persistence.tables
-   synapse.persistence.transactions
-
-Module contents
----------------
-
-.. automodule:: synapse.persistence
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.persistence.service.rst b/docs/sphinx/synapse.persistence.service.rst
deleted file mode 100644
index 3514d3c76f..0000000000
--- a/docs/sphinx/synapse.persistence.service.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.persistence.service module
-==================================
-
-.. automodule:: synapse.persistence.service
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.persistence.tables.rst b/docs/sphinx/synapse.persistence.tables.rst
deleted file mode 100644
index 907b02769d..0000000000
--- a/docs/sphinx/synapse.persistence.tables.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.persistence.tables module
-=================================
-
-.. automodule:: synapse.persistence.tables
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.persistence.transactions.rst b/docs/sphinx/synapse.persistence.transactions.rst
deleted file mode 100644
index 475c02a8c5..0000000000
--- a/docs/sphinx/synapse.persistence.transactions.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.persistence.transactions module
-=======================================
-
-.. automodule:: synapse.persistence.transactions
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.rest.base.rst b/docs/sphinx/synapse.rest.base.rst
deleted file mode 100644
index 84d2d9b31d..0000000000
--- a/docs/sphinx/synapse.rest.base.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.rest.base module
-========================
-
-.. automodule:: synapse.rest.base
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.rest.events.rst b/docs/sphinx/synapse.rest.events.rst
deleted file mode 100644
index ebbe26c746..0000000000
--- a/docs/sphinx/synapse.rest.events.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.rest.events module
-==========================
-
-.. automodule:: synapse.rest.events
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.rest.register.rst b/docs/sphinx/synapse.rest.register.rst
deleted file mode 100644
index a4a48a8a8f..0000000000
--- a/docs/sphinx/synapse.rest.register.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.rest.register module
-============================
-
-.. automodule:: synapse.rest.register
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.rest.room.rst b/docs/sphinx/synapse.rest.room.rst
deleted file mode 100644
index 63fc5c2840..0000000000
--- a/docs/sphinx/synapse.rest.room.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.rest.room module
-========================
-
-.. automodule:: synapse.rest.room
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.rest.rst b/docs/sphinx/synapse.rest.rst
deleted file mode 100644
index 016af926b2..0000000000
--- a/docs/sphinx/synapse.rest.rst
+++ /dev/null
@@ -1,20 +0,0 @@
-synapse.rest package
-====================
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.rest.base
-   synapse.rest.events
-   synapse.rest.register
-   synapse.rest.room
-
-Module contents
----------------
-
-.. automodule:: synapse.rest
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.rst b/docs/sphinx/synapse.rst
deleted file mode 100644
index e7869e0e5d..0000000000
--- a/docs/sphinx/synapse.rst
+++ /dev/null
@@ -1,30 +0,0 @@
-synapse package
-===============
-
-Subpackages
------------
-
-.. toctree::
-
-    synapse.api
-    synapse.app
-    synapse.federation
-    synapse.persistence
-    synapse.rest
-    synapse.util
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.server
-   synapse.state
-
-Module contents
----------------
-
-.. automodule:: synapse
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.server.rst b/docs/sphinx/synapse.server.rst
deleted file mode 100644
index 7f33f084d7..0000000000
--- a/docs/sphinx/synapse.server.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.server module
-=====================
-
-.. automodule:: synapse.server
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.state.rst b/docs/sphinx/synapse.state.rst
deleted file mode 100644
index 744be2a8be..0000000000
--- a/docs/sphinx/synapse.state.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.state module
-====================
-
-.. automodule:: synapse.state
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.util.async.rst b/docs/sphinx/synapse.util.async.rst
deleted file mode 100644
index 542bb54444..0000000000
--- a/docs/sphinx/synapse.util.async.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.util.async module
-=========================
-
-.. automodule:: synapse.util.async
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.util.dbutils.rst b/docs/sphinx/synapse.util.dbutils.rst
deleted file mode 100644
index afaa9eb749..0000000000
--- a/docs/sphinx/synapse.util.dbutils.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.util.dbutils module
-===========================
-
-.. automodule:: synapse.util.dbutils
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.util.http.rst b/docs/sphinx/synapse.util.http.rst
deleted file mode 100644
index 344af5a490..0000000000
--- a/docs/sphinx/synapse.util.http.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.util.http module
-========================
-
-.. automodule:: synapse.util.http
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.util.lockutils.rst b/docs/sphinx/synapse.util.lockutils.rst
deleted file mode 100644
index 16ee26cabd..0000000000
--- a/docs/sphinx/synapse.util.lockutils.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.util.lockutils module
-=============================
-
-.. automodule:: synapse.util.lockutils
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.util.logutils.rst b/docs/sphinx/synapse.util.logutils.rst
deleted file mode 100644
index 2b79fa7a4b..0000000000
--- a/docs/sphinx/synapse.util.logutils.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.util.logutils module
-============================
-
-.. automodule:: synapse.util.logutils
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.util.rst b/docs/sphinx/synapse.util.rst
deleted file mode 100644
index 01a0c3a591..0000000000
--- a/docs/sphinx/synapse.util.rst
+++ /dev/null
@@ -1,21 +0,0 @@
-synapse.util package
-====================
-
-Submodules
-----------
-
-.. toctree::
-
-   synapse.util.async
-   synapse.util.http
-   synapse.util.lockutils
-   synapse.util.logutils
-   synapse.util.stringutils
-
-Module contents
----------------
-
-.. automodule:: synapse.util
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sphinx/synapse.util.stringutils.rst b/docs/sphinx/synapse.util.stringutils.rst
deleted file mode 100644
index ec626eee28..0000000000
--- a/docs/sphinx/synapse.util.stringutils.rst
+++ /dev/null
@@ -1,7 +0,0 @@
-synapse.util.stringutils module
-===============================
-
-.. automodule:: synapse.util.stringutils
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/sso_mapping_providers.md b/docs/sso_mapping_providers.md
index 32b06aa2c5..ab2a648910 100644
--- a/docs/sso_mapping_providers.md
+++ b/docs/sso_mapping_providers.md
@@ -15,8 +15,15 @@ where SAML mapping providers come into play.
 SSO mapping providers are currently supported for OpenID and SAML SSO
 configurations. Please see the details below for how to implement your own.
 
+It is the responsibility of the mapping provider to normalise the SSO attributes
+and map them to a valid Matrix ID. The
+[specification for Matrix IDs](https://matrix.org/docs/spec/appendices#user-identifiers)
+has some information about what is considered valid. Alternately an easy way to
+ensure it is valid is to use a Synapse utility function:
+`synapse.types.map_username_to_mxid_localpart`.
+
 External mapping providers are provided to Synapse in the form of an external
-Python module. You can retrieve this module from [PyPi](https://pypi.org) or elsewhere,
+Python module. You can retrieve this module from [PyPI](https://pypi.org) or elsewhere,
 but it must be importable via Synapse (e.g. it must be in the same virtualenv
 as Synapse). The Synapse config is then modified to point to the mapping provider
 (and optionally provide additional configuration for it).
@@ -56,13 +63,22 @@ A custom mapping provider must specify the following methods:
                      information from.
     - This method must return a string, which is the unique identifier for the
       user. Commonly the ``sub`` claim of the response.
-* `map_user_attributes(self, userinfo, token)`
+* `map_user_attributes(self, userinfo, token, failures)`
     - This method must be async.
     - Arguments:
       - `userinfo` - A `authlib.oidc.core.claims.UserInfo` object to extract user
                      information from.
       - `token` - A dictionary which includes information necessary to make
                   further requests to the OpenID provider.
+      - `failures` - An `int` that represents the amount of times the returned
+                     mxid localpart mapping has failed.  This should be used
+                     to create a deduplicated mxid localpart which should be
+                     returned instead. For example, if this method returns
+                     `john.doe` as the value of `localpart` in the returned
+                     dict, and that is already taken on the homeserver, this
+                     method will be called again with the same parameters but
+                     with failures=1. The method should then return a different
+                     `localpart` value, such as `john.doe1`.
     - Returns a dictionary with two keys:
       - localpart: A required string, used to generate the Matrix ID.
       - displayname: An optional string, the display name for the user.
@@ -152,6 +168,13 @@ A custom mapping provider must specify the following methods:
                          the value of `mxid_localpart`.
        * `emails` - A list of emails for the new user. If not provided, will
                     default to an empty list.
+       
+       Alternatively it can raise a `synapse.api.errors.RedirectException` to
+       redirect the user to another page. This is useful to prompt the user for
+       additional information, e.g. if you want them to provide their own username.
+       It is the responsibility of the mapping provider to either redirect back
+       to `client_redirect_url` (including any additional information) or to
+       complete registration using methods from the `ModuleApi`.
 
 ### Default SAML Mapping Provider
 
diff --git a/docs/structured_logging.md b/docs/structured_logging.md
index decec9b8fa..b1281667e0 100644
--- a/docs/structured_logging.md
+++ b/docs/structured_logging.md
@@ -1,11 +1,116 @@
 # Structured Logging
 
-A structured logging system can be useful when your logs are destined for a machine to parse and process. By maintaining its machine-readable characteristics, it enables more efficient searching and aggregations when consumed by software such as the "ELK stack".
+A structured logging system can be useful when your logs are destined for a
+machine to parse and process. By maintaining its machine-readable characteristics,
+it enables more efficient searching and aggregations when consumed by software
+such as the "ELK stack".
 
-Synapse's structured logging system is configured via the file that Synapse's `log_config` config option points to. The file must be YAML and contain `structured: true`. It must contain a list of "drains" (places where logs go to).
+Synapse's structured logging system is configured via the file that Synapse's
+`log_config` config option points to. The file should include a formatter which
+uses the `synapse.logging.TerseJsonFormatter` class included with Synapse and a
+handler which uses the above formatter.
+
+There is also a `synapse.logging.JsonFormatter` option which does not include
+a timestamp in the resulting JSON. This is useful if the log ingester adds its
+own timestamp.
 
 A structured logging configuration looks similar to the following:
 
+```yaml
+version: 1
+
+formatters:
+    structured:
+        class: synapse.logging.TerseJsonFormatter
+
+handlers:
+    file:
+        class: logging.handlers.TimedRotatingFileHandler
+        formatter: structured
+        filename: /path/to/my/logs/homeserver.log
+        when: midnight
+        backupCount: 3  # Does not include the current log file.
+        encoding: utf8
+
+loggers:
+    synapse:
+        level: INFO
+        handlers: [remote]
+    synapse.storage.SQL:
+        level: WARNING
+```
+
+The above logging config will set Synapse as 'INFO' logging level by default,
+with the SQL layer at 'WARNING', and will log to a file, stored as JSON.
+
+It is also possible to figure Synapse to log to a remote endpoint by using the
+`synapse.logging.RemoteHandler` class included with Synapse. It takes the
+following arguments:
+
+- `host`: Hostname or IP address of the log aggregator.
+- `port`: Numerical port to contact on the host.
+- `maximum_buffer`: (Optional, defaults to 1000) The maximum buffer size to allow.
+
+A remote structured logging configuration looks similar to the following:
+
+```yaml
+version: 1
+
+formatters:
+    structured:
+        class: synapse.logging.TerseJsonFormatter
+
+handlers:
+    remote:
+        class: synapse.logging.RemoteHandler
+        formatter: structured
+        host: 10.1.2.3
+        port: 9999
+
+loggers:
+    synapse:
+        level: INFO
+        handlers: [remote]
+    synapse.storage.SQL:
+        level: WARNING
+```
+
+The above logging config will set Synapse as 'INFO' logging level by default,
+with the SQL layer at 'WARNING', and will log JSON formatted messages to a
+remote endpoint at 10.1.2.3:9999.
+
+## Upgrading from legacy structured logging configuration
+
+Versions of Synapse prior to v1.23.0 included a custom structured logging
+configuration which is deprecated. It used a `structured: true` flag and
+configured `drains` instead of ``handlers`` and `formatters`.
+
+Synapse currently automatically converts the old configuration to the new
+configuration, but this will be removed in a future version of Synapse. The
+following reference can be used to update your configuration. Based on the drain
+`type`, we can pick a new handler:
+
+1. For a type of `console`, `console_json`, or `console_json_terse`: a handler
+   with a class of `logging.StreamHandler` and a `stream` of `ext://sys.stdout`
+   or `ext://sys.stderr` should be used.
+2. For a type of `file` or `file_json`: a handler of `logging.FileHandler` with
+   a location of the file path should be used.
+3. For a type of `network_json_terse`: a handler of `synapse.logging.RemoteHandler`
+   with the host and port should be used.
+
+Then based on the drain `type` we can pick a new formatter:
+
+1. For a type of `console` or `file` no formatter is necessary.
+2. For a type of `console_json` or `file_json`: a formatter of
+   `synapse.logging.JsonFormatter` should be used.
+3. For a type of `console_json_terse` or `network_json_terse`: a formatter of
+   `synapse.logging.TerseJsonFormatter` should be used.
+
+For each new handler and formatter they should be added to the logging configuration
+and then assigned to either a logger or the root logger.
+
+An example legacy configuration:
+
 ```yaml
 structured: true
 
@@ -24,60 +129,33 @@ drains:
         location: homeserver.log
 ```
 
-The above logging config will set Synapse as 'INFO' logging level by default, with the SQL layer at 'WARNING', and will have two logging drains (to the console and to a file, stored as JSON).
+Would be converted into a new configuration:
 
-## Drain Types
+```yaml
+version: 1
 
-Drain types can be specified by the `type` key.
+formatters:
+    json:
+        class: synapse.logging.JsonFormatter
 
-### `console`
+handlers:
+    console:
+        class: logging.StreamHandler
+        location: ext://sys.stdout
+    file:
+        class: logging.FileHandler
+        formatter: json
+        filename: homeserver.log
 
-Outputs human-readable logs to the console.
+loggers:
+    synapse:
+        level: INFO
+        handlers: [console, file]
+    synapse.storage.SQL:
+        level: WARNING
+```
 
-Arguments:
-
-- `location`: Either `stdout` or `stderr`.
-
-### `console_json`
-
-Outputs machine-readable JSON logs to the console.
-
-Arguments:
-
-- `location`: Either `stdout` or `stderr`.
-
-### `console_json_terse`
-
-Outputs machine-readable JSON logs to the console, separated by newlines. This
-format is not designed to be read and re-formatted into human-readable text, but
-is optimal for a logging aggregation system.
-
-Arguments:
-
-- `location`: Either `stdout` or `stderr`.
-
-### `file`
-
-Outputs human-readable logs to a file.
-
-Arguments:
-
-- `location`: An absolute path to the file to log to.
-
-### `file_json`
-
-Outputs machine-readable logs to a file.
-
-Arguments:
-
-- `location`: An absolute path to the file to log to.
-
-### `network_json_terse`
-
-Delivers machine-readable JSON logs to a log aggregator over TCP. This is
-compatible with LogStash's TCP input with the codec set to `json_lines`.
-
-Arguments:
-
-- `host`: Hostname or IP address of the log aggregator.
-- `port`: Numerical port to contact on the host.
\ No newline at end of file
+The new logging configuration is a bit more verbose, but significantly more
+flexible. It allows for configuration that were not previously possible, such as
+sending plain logs over the network, or using different handlers for different
+modules.
diff --git a/docs/systemd-with-workers/README.md b/docs/systemd-with-workers/README.md
index 257c09446f..8e57d4f62e 100644
--- a/docs/systemd-with-workers/README.md
+++ b/docs/systemd-with-workers/README.md
@@ -37,10 +37,10 @@ synapse master process to be started as part of the `matrix-synapse.target`
 target.
 1. For each worker process to be enabled, run `systemctl enable
 matrix-synapse-worker@<worker_name>.service`. For each `<worker_name>`, there
-should be a corresponding configuration file
+should be a corresponding configuration file.
 `/etc/matrix-synapse/workers/<worker_name>.yaml`.
 1. Start all the synapse processes with `systemctl start matrix-synapse.target`.
-1. Tell systemd to start synapse on boot with `systemctl enable matrix-synapse.target`/
+1. Tell systemd to start synapse on boot with `systemctl enable matrix-synapse.target`.
 
 ## Usage
 
diff --git a/docs/tcp_replication.md b/docs/tcp_replication.md
index db318baa9d..ad145439b4 100644
--- a/docs/tcp_replication.md
+++ b/docs/tcp_replication.md
@@ -15,7 +15,7 @@ example flow would be (where '>' indicates master to worker and
 
     > SERVER example.com
     < REPLICATE
-    > POSITION events master 53
+    > POSITION events master 53 53
     > RDATA events master 54 ["$foo1:bar.com", ...]
     > RDATA events master 55 ["$foo4:bar.com", ...]
 
@@ -138,9 +138,9 @@ the wire:
     < NAME synapse.app.appservice
     < PING 1490197665618
     < REPLICATE
-    > POSITION events master 1
-    > POSITION backfill master 1
-    > POSITION caches master 1
+    > POSITION events master 1 1
+    > POSITION backfill master 1 1
+    > POSITION caches master 1 1
     > RDATA caches master 2 ["get_user_by_id",["@01register-user:localhost:8823"],1490197670513]
     > RDATA events master 14 ["$149019767112vOHxz:localhost:8823",
         "!AFDCvgApUmpdfVjIXm:localhost:8823","m.room.guest_access","",null]
@@ -185,6 +185,11 @@ client (C):
    updates via HTTP API, rather than via the DB, then processes should make the
    request to the appropriate process.
 
+   Two positions are included, the "new" position and the last position sent respectively.
+   This allows servers to tell instances that the positions have advanced but no
+   data has been written, without clients needlessly checking to see if they
+   have missed any updates.
+
 #### ERROR (S, C)
 
    There was an error
diff --git a/docs/turn-howto.md b/docs/turn-howto.md
index d4a726be66..a470c274a5 100644
--- a/docs/turn-howto.md
+++ b/docs/turn-howto.md
@@ -42,10 +42,10 @@ This will install and start a systemd service called `coturn`.
 
         ./configure
 
-    > You may need to install `libevent2`: if so, you should do so in
-    > the way recommended by your operating system. You can ignore
-    > warnings about lack of database support: a database is unnecessary
-    > for this purpose.
+    You may need to install `libevent2`: if so, you should do so in
+    the way recommended by your operating system. You can ignore
+    warnings about lack of database support: a database is unnecessary
+    for this purpose.
 
 1.  Build and install it:
 
@@ -66,6 +66,19 @@ This will install and start a systemd service called `coturn`.
 
         pwgen -s 64 1
 
+    A `realm` must be specified, but its value is somewhat arbitrary. (It is
+    sent to clients as part of the authentication flow.) It is conventional to
+    set it to be your server name.
+
+1.  You will most likely want to configure coturn to write logs somewhere. The
+    easiest way is normally to send them to the syslog:
+
+        syslog
+
+    (in which case, the logs will be available via `journalctl -u coturn` on a
+    systemd system). Alternatively, coturn can be configured to write to a
+    logfile - check the example config file supplied with coturn.
+
 1.  Consider your security settings. TURN lets users request a relay which will
     connect to arbitrary IP addresses and ports. The following configuration is
     suggested as a minimum starting point:
@@ -96,11 +109,31 @@ This will install and start a systemd service called `coturn`.
         # TLS private key file
         pkey=/path/to/privkey.pem
 
+    In this case, replace the `turn:` schemes in the `turn_uri` settings below
+    with `turns:`.
+
+    We recommend that you only try to set up TLS/DTLS once you have set up a
+    basic installation and got it working.
+
 1.  Ensure your firewall allows traffic into the TURN server on the ports
-    you've configured it to listen on (By default: 3478 and 5349 for the TURN(s)
+    you've configured it to listen on (By default: 3478 and 5349 for TURN
     traffic (remember to allow both TCP and UDP traffic), and ports 49152-65535
     for the UDP relay.)
 
+1.  We do not recommend running a TURN server behind NAT, and are not aware of
+    anyone doing so successfully.
+
+    If you want to try it anyway, you will at least need to tell coturn its
+    external IP address:
+
+        external-ip=192.88.99.1
+
+    ... and your NAT gateway must forward all of the relayed ports directly
+    (eg, port 56789 on the external IP must be always be forwarded to port
+    56789 on the internal IP).
+
+    If you get this working, let us know!
+
 1.  (Re)start the turn server:
 
     * If you used the Debian package (or have set up a systemd unit yourself):
@@ -137,9 +170,10 @@ Your home server configuration file needs the following extra keys:
     without having gone through a CAPTCHA or similar to register a
     real account.
 
-As an example, here is the relevant section of the config file for matrix.org:
+As an example, here is the relevant section of the config file for `matrix.org`. The
+`turn_uris` are appropriate for TURN servers listening on the default ports, with no TLS.
 
-    turn_uris: [ "turn:turn.matrix.org:3478?transport=udp", "turn:turn.matrix.org:3478?transport=tcp" ]
+    turn_uris: [ "turn:turn.matrix.org?transport=udp", "turn:turn.matrix.org?transport=tcp" ]
     turn_shared_secret: "n0t4ctuAllymatr1Xd0TorgSshar3d5ecret4obvIousreAsons"
     turn_user_lifetime: 86400000
     turn_allow_guests: True
@@ -155,5 +189,86 @@ After updating the homeserver configuration, you must restart synapse:
     ```
     systemctl restart synapse.service
     ```
+... and then reload any clients (or wait an hour for them to refresh their
+settings).
 
-..and your Home Server now supports VoIP relaying!
+## Troubleshooting
+
+The normal symptoms of a misconfigured TURN server are that calls between
+devices on different networks ring, but get stuck at "call
+connecting". Unfortunately, troubleshooting this can be tricky.
+
+Here are a few things to try:
+
+ * Check that your TURN server is not behind NAT. As above, we're not aware of
+   anyone who has successfully set this up.
+
+ * Check that you have opened your firewall to allow TCP and UDP traffic to the
+   TURN ports (normally 3478 and 5479).
+
+ * Check that you have opened your firewall to allow UDP traffic to the UDP
+   relay ports (49152-65535 by default).
+
+ * Some WebRTC implementations (notably, that of Google Chrome) appear to get
+   confused by TURN servers which are reachable over IPv6 (this appears to be
+   an unexpected side-effect of its handling of multiple IP addresses as
+   defined by
+   [`draft-ietf-rtcweb-ip-handling`](https://tools.ietf.org/html/draft-ietf-rtcweb-ip-handling-12)).
+
+   Try removing any AAAA records for your TURN server, so that it is only
+   reachable over IPv4.
+
+ * Enable more verbose logging in coturn via the `verbose` setting:
+
+   ```
+   verbose
+   ```
+
+   ... and then see if there are any clues in its logs.
+
+ * If you are using a browser-based client under Chrome, check
+   `chrome://webrtc-internals/` for insights into the internals of the
+   negotiation. On Firefox, check the "Connection Log" on `about:webrtc`.
+
+   (Understanding the output is beyond the scope of this document!)
+
+ * There is a WebRTC test tool at
+   https://webrtc.github.io/samples/src/content/peerconnection/trickle-ice/. To
+   use it, you will need a username/password for your TURN server. You can
+   either:
+
+    * look for the `GET /_matrix/client/r0/voip/turnServer` request made by a
+      matrix client to your homeserver in your browser's network inspector. In
+      the response you should see `username` and `password`. Or:
+
+    * Use the following shell commands:
+
+      ```sh
+      secret=staticAuthSecretHere
+
+      u=$((`date +%s` + 3600)):test
+      p=$(echo -n $u | openssl dgst -hmac $secret -sha1 -binary | base64)
+      echo -e "username: $u\npassword: $p"
+      ```
+
+      Or:
+
+    * Temporarily configure coturn to accept a static username/password. To do
+      this, comment out `use-auth-secret` and `static-auth-secret` and add the
+      following:
+
+      ```
+      lt-cred-mech
+      user=username:password
+      ```
+
+      **Note**: these settings will not take effect unless `use-auth-secret`
+      and `static-auth-secret` are disabled.
+
+      Restart coturn after changing the configuration file.
+
+      Remember to restore the original settings to go back to testing with
+      Matrix clients!
+
+   If the TURN server is working correctly, you should see at least one `relay`
+   entry in the results.
diff --git a/docs/workers.md b/docs/workers.md
index ad4d8ca9f2..c53d1bd2ff 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -116,7 +116,7 @@ public internet; it has no authentication and is unencrypted.
 ### Worker configuration
 
 In the config file for each worker, you must specify the type of worker
-application (`worker_app`), and you should specify a unqiue name for the worker
+application (`worker_app`), and you should specify a unique name for the worker
 (`worker_name`). The currently available worker applications are listed below.
 You must also specify the HTTP replication endpoint that it should talk to on
 the main synapse process.  `worker_replication_host` should specify the host of
@@ -262,6 +262,9 @@ using):
 Note that a HTTP listener with `client` and `federation` resources must be
 configured in the `worker_listeners` option in the worker config.
 
+Ensure that all SSO logins go to a single process (usually the main process). 
+For multiple workers not handling the SSO endpoints properly, see
+[#7530](https://github.com/matrix-org/synapse/issues/7530).
 
 #### Load balancing
 
@@ -302,7 +305,7 @@ Additionally, there is *experimental* support for moving writing of specific
 streams (such as events) off of the main process to a particular worker. (This
 is only supported with Redis-based replication.)
 
-Currently support streams are `events` and `typing`.
+Currently supported streams are `events` and `typing`.
 
 To enable this, the worker must have a HTTP replication listener configured,
 have a `worker_name` and be listed in the `instance_map` config. For example to
@@ -319,6 +322,35 @@ stream_writers:
     events: event_persister1
 ```
 
+The `events` stream also experimentally supports having multiple writers, where
+work is sharded between them by room ID. Note that you *must* restart all worker
+instances when adding or removing event persisters. An example `stream_writers`
+configuration with multiple writers:
+
+```yaml
+stream_writers:
+    events:
+        - event_persister1
+        - event_persister2
+```
+
+#### Background tasks
+
+There is also *experimental* support for moving background tasks to a separate
+worker. Background tasks are run periodically or started via replication. Exactly
+which tasks are configured to run depends on your Synapse configuration (e.g. if
+stats is enabled).
+
+To enable this, the worker must have a `worker_name` and can be configured to run
+background tasks. For example, to move background tasks to a dedicated worker,
+the shared configuration would include:
+
+```yaml
+run_background_tasks_on: background_worker
+```
+
+You might also wish to investigate the `update_user_directory` and
+`media_instance_running_background_jobs` settings.
 
 ### `synapse.app.pusher`
 
@@ -391,6 +423,8 @@ and you must configure a single instance to run the background tasks, e.g.:
     media_instance_running_background_jobs: "media-repository-1"
 ```
 
+Note that if a reverse proxy is used , then `/_matrix/media/` must be routed for both inbound client and federation requests (if they are handled separately).
+
 ### `synapse.app.user_dir`
 
 Handles searches in the user directory. It can handle REST endpoints matching
diff --git a/mypy.ini b/mypy.ini
index 7986781432..3c8d303064 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -6,16 +6,26 @@ check_untyped_defs = True
 show_error_codes = True
 show_traceback = True
 mypy_path = stubs
+warn_unreachable = True
 files =
+  scripts-dev/sign_json,
   synapse/api,
   synapse/appservice,
   synapse/config,
   synapse/event_auth.py,
   synapse/events/builder.py,
+  synapse/events/validator.py,
   synapse/events/spamcheck.py,
   synapse/federation,
+  synapse/handlers/_base.py,
+  synapse/handlers/account_data.py,
+  synapse/handlers/account_validity.py,
+  synapse/handlers/appservice.py,
   synapse/handlers/auth.py,
   synapse/handlers/cas_handler.py,
+  synapse/handlers/deactivate_account.py,
+  synapse/handlers/device.py,
+  synapse/handlers/devicemessage.py,
   synapse/handlers/directory.py,
   synapse/handlers/events.py,
   synapse/handlers/federation.py,
@@ -24,14 +34,21 @@ files =
   synapse/handlers/message.py,
   synapse/handlers/oidc_handler.py,
   synapse/handlers/pagination.py,
+  synapse/handlers/password_policy.py,
   synapse/handlers/presence.py,
+  synapse/handlers/profile.py,
+  synapse/handlers/read_marker.py,
+  synapse/handlers/register.py,
   synapse/handlers/room.py,
   synapse/handlers/room_member.py,
   synapse/handlers/room_member_worker.py,
   synapse/handlers/saml_handler.py,
   synapse/handlers/sync.py,
   synapse/handlers/ui_auth,
+  synapse/http/client.py,
+  synapse/http/federation/matrix_federation_agent.py,
   synapse/http/federation/well_known_resolver.py,
+  synapse/http/matrixfederationclient.py,
   synapse/http/server.py,
   synapse/http/site.py,
   synapse/logging,
@@ -46,7 +63,9 @@ files =
   synapse/server_notices,
   synapse/spam_checker_api,
   synapse/state,
+  synapse/storage/databases/main/appservice.py,
   synapse/storage/databases/main/events.py,
+  synapse/storage/databases/main/registration.py,
   synapse/storage/databases/main/stream.py,
   synapse/storage/databases/main/ui_auth.py,
   synapse/storage/database.py,
@@ -57,11 +76,11 @@ files =
   synapse/streams,
   synapse/types.py,
   synapse/util/async_helpers.py,
-  synapse/util/caches/descriptors.py,
-  synapse/util/caches/stream_change_cache.py,
+  synapse/util/caches,
   synapse/util/metrics.py,
   tests/replication,
   tests/test_utils,
+  tests/handlers/test_password_providers.py,
   tests/rest/client/v2_alpha/test_auth.py,
   tests/util/test_stream_change_cache.py
 
@@ -71,6 +90,9 @@ ignore_missing_imports = True
 [mypy-zope]
 ignore_missing_imports = True
 
+[mypy-bcrypt]
+ignore_missing_imports = True
+
 [mypy-constantly]
 ignore_missing_imports = True
 
@@ -89,7 +111,7 @@ ignore_missing_imports = True
 [mypy-opentracing]
 ignore_missing_imports = True
 
-[mypy-OpenSSL]
+[mypy-OpenSSL.*]
 ignore_missing_imports = True
 
 [mypy-netaddr]
@@ -142,3 +164,6 @@ ignore_missing_imports = True
 
 [mypy-nacl.*]
 ignore_missing_imports = True
+
+[mypy-hiredis]
+ignore_missing_imports = True
diff --git a/pyproject.toml b/pyproject.toml
index db4a2e41e4..cd880d4e39 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,7 +35,7 @@
         showcontent = true
 
 [tool.black]
-target-version = ['py34']
+target-version = ['py35']
 exclude = '''
 
 (
diff --git a/scripts-dev/lint.sh b/scripts-dev/lint.sh
index 0647993658..f328ab57d5 100755
--- a/scripts-dev/lint.sh
+++ b/scripts-dev/lint.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 # Runs linting scripts over the local Synapse checkout
 # isort - sorts import statements
@@ -7,15 +7,91 @@
 
 set -e
 
-if [ $# -ge 1 ]
-then
-  files=$*
-else
-  files="synapse tests scripts-dev scripts contrib synctl"
+usage() {
+  echo
+  echo "Usage: $0 [-h] [-d] [paths...]"
+  echo
+  echo "-d"
+  echo "  Lint files that have changed since the last git commit."
+  echo
+  echo "  If paths are provided and this option is set, both provided paths and those"
+  echo "  that have changed since the last commit will be linted."
+  echo
+  echo "  If no paths are provided and this option is not set, all files will be linted."
+  echo
+  echo "  Note that paths with a file extension that is not '.py' will be excluded."
+  echo "-h"
+  echo "  Display this help text."
+}
+
+USING_DIFF=0
+files=()
+
+while getopts ":dh" opt; do
+  case $opt in
+    d)
+      USING_DIFF=1
+      ;;
+    h)
+      usage
+      exit
+      ;;
+    \?)
+      echo "ERROR: Invalid option: -$OPTARG" >&2
+      usage
+      exit
+      ;;
+  esac
+done
+
+# Strip any options from the command line arguments now that
+# we've finished processing them
+shift "$((OPTIND-1))"
+
+if [ $USING_DIFF -eq 1 ]; then
+  # Check both staged and non-staged changes
+  for path in $(git diff HEAD --name-only); do
+    filename=$(basename "$path")
+    file_extension="${filename##*.}"
+
+    # If an extension is present, and it's something other than 'py',
+    # then ignore this file
+    if [[ -n ${file_extension+x} && $file_extension != "py" ]]; then
+      continue
+    fi
+
+    # Append this path to our list of files to lint
+    files+=("$path")
+  done
 fi
 
-echo "Linting these locations: $files"
-isort $files
-python3 -m black $files
+# Append any remaining arguments as files to lint
+files+=("$@")
+
+if [[ $USING_DIFF -eq 1 ]]; then
+  # If we were asked to lint changed files, and no paths were found as a result...
+  if [ ${#files[@]} -eq 0 ]; then
+    # Then print and exit
+    echo "No files found to lint."
+    exit 0
+  fi
+else
+  # If we were not asked to lint changed files, and no paths were found as a result,
+  # then lint everything!
+  if [[ -z ${files+x} ]]; then
+    # Lint all source code files and directories
+    files=("synapse" "tests" "scripts-dev" "scripts" "contrib" "synctl" "setup.py" "synmark")
+  fi
+fi
+
+echo "Linting these paths: ${files[*]}"
+echo
+
+# Print out the commands being run
+set -x
+
+isort "${files[@]}"
+python3 -m black "${files[@]}"
 ./scripts-dev/config-lint.sh
-flake8 $files
+flake8 "${files[@]}"
+mypy
diff --git a/scripts-dev/mypy_synapse_plugin.py b/scripts-dev/mypy_synapse_plugin.py
index a5b88731f1..5882f3a0b0 100644
--- a/scripts-dev/mypy_synapse_plugin.py
+++ b/scripts-dev/mypy_synapse_plugin.py
@@ -19,9 +19,10 @@ can crop up, e.g the cache descriptors.
 
 from typing import Callable, Optional
 
+from mypy.nodes import ARG_NAMED_OPT
 from mypy.plugin import MethodSigContext, Plugin
 from mypy.typeops import bind_self
-from mypy.types import CallableType
+from mypy.types import CallableType, NoneType
 
 
 class SynapsePlugin(Plugin):
@@ -40,8 +41,9 @@ def cached_function_method_signature(ctx: MethodSigContext) -> CallableType:
 
     It already has *almost* the correct signature, except:
 
-        1. the `self` argument needs to be marked as "bound"; and
-        2. any `cache_context` argument should be removed.
+        1. the `self` argument needs to be marked as "bound";
+        2. any `cache_context` argument should be removed;
+        3. an optional keyword argument `on_invalidated` should be added.
     """
 
     # First we mark this as a bound function signature.
@@ -58,19 +60,33 @@ def cached_function_method_signature(ctx: MethodSigContext) -> CallableType:
             context_arg_index = idx
             break
 
+    arg_types = list(signature.arg_types)
+    arg_names = list(signature.arg_names)
+    arg_kinds = list(signature.arg_kinds)
+
     if context_arg_index:
-        arg_types = list(signature.arg_types)
         arg_types.pop(context_arg_index)
-
-        arg_names = list(signature.arg_names)
         arg_names.pop(context_arg_index)
-
-        arg_kinds = list(signature.arg_kinds)
         arg_kinds.pop(context_arg_index)
 
-        signature = signature.copy_modified(
-            arg_types=arg_types, arg_names=arg_names, arg_kinds=arg_kinds,
-        )
+    # Third, we add an optional "on_invalidate" argument.
+    #
+    # This is a callable which accepts no input and returns nothing.
+    calltyp = CallableType(
+        arg_types=[],
+        arg_kinds=[],
+        arg_names=[],
+        ret_type=NoneType(),
+        fallback=ctx.api.named_generic_type("builtins.function", []),
+    )
+
+    arg_types.append(calltyp)
+    arg_names.append("on_invalidate")
+    arg_kinds.append(ARG_NAMED_OPT)  # Arg is an optional kwarg.
+
+    signature = signature.copy_modified(
+        arg_types=arg_types, arg_names=arg_names, arg_kinds=arg_kinds,
+    )
 
     return signature
 
diff --git a/scripts-dev/sign_json b/scripts-dev/sign_json
new file mode 100755
index 0000000000..44553fb79a
--- /dev/null
+++ b/scripts-dev/sign_json
@@ -0,0 +1,127 @@
+#!/usr/bin/env python
+#
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import argparse
+import json
+import sys
+from json import JSONDecodeError
+
+import yaml
+from signedjson.key import read_signing_keys
+from signedjson.sign import sign_json
+
+from synapse.util import json_encoder
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="""Adds a signature to a JSON object.
+
+Example usage:
+
+    $ scripts-dev/sign_json.py -N test -k localhost.signing.key "{}"
+    {"signatures":{"test":{"ed25519:a_ZnZh":"LmPnml6iM0iR..."}}}
+""",
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+
+    parser.add_argument(
+        "-N",
+        "--server-name",
+        help="Name to give as the local homeserver. If unspecified, will be "
+        "read from the config file.",
+    )
+
+    parser.add_argument(
+        "-k",
+        "--signing-key-path",
+        help="Path to the file containing the private ed25519 key to sign the "
+        "request with.",
+    )
+
+    parser.add_argument(
+        "-c",
+        "--config",
+        default="homeserver.yaml",
+        help=(
+            "Path to synapse config file, from which the server name and/or signing "
+            "key path will be read. Ignored if --server-name and --signing-key-path "
+            "are both given."
+        ),
+    )
+
+    input_args = parser.add_mutually_exclusive_group()
+
+    input_args.add_argument("input_data", nargs="?", help="Raw JSON to be signed.")
+
+    input_args.add_argument(
+        "-i",
+        "--input",
+        type=argparse.FileType("r"),
+        default=sys.stdin,
+        help=(
+            "A file from which to read the JSON to be signed. If neither --input nor "
+            "input_data are given, JSON will be read from stdin."
+        ),
+    )
+
+    parser.add_argument(
+        "-o",
+        "--output",
+        type=argparse.FileType("w"),
+        default=sys.stdout,
+        help="Where to write the signed JSON. Defaults to stdout.",
+    )
+
+    args = parser.parse_args()
+
+    if not args.server_name or not args.signing_key_path:
+        read_args_from_config(args)
+
+    with open(args.signing_key_path) as f:
+        key = read_signing_keys(f)[0]
+
+    json_to_sign = args.input_data
+    if json_to_sign is None:
+        json_to_sign = args.input.read()
+
+    try:
+        obj = json.loads(json_to_sign)
+    except JSONDecodeError as e:
+        print("Unable to parse input as JSON: %s" % e, file=sys.stderr)
+        sys.exit(1)
+
+    if not isinstance(obj, dict):
+        print("Input json was not an object", file=sys.stderr)
+        sys.exit(1)
+
+    sign_json(obj, args.server_name, key)
+    for c in json_encoder.iterencode(obj):
+        args.output.write(c)
+    args.output.write("\n")
+
+
+def read_args_from_config(args: argparse.Namespace) -> None:
+    with open(args.config, "r") as fh:
+        config = yaml.safe_load(fh)
+        if not args.server_name:
+            args.server_name = config["server_name"]
+        if not args.signing_key_path:
+            args.signing_key_path = config["signing_key_path"]
+
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts-dev/sphinx_api_docs.sh b/scripts-dev/sphinx_api_docs.sh
deleted file mode 100644
index ee72b29657..0000000000
--- a/scripts-dev/sphinx_api_docs.sh
+++ /dev/null
@@ -1 +0,0 @@
-sphinx-apidoc -o docs/sphinx/ synapse/ -ef
diff --git a/scripts/synapse_port_db b/scripts/synapse_port_db
index dd1ebde894..c982ca9350 100755
--- a/scripts/synapse_port_db
+++ b/scripts/synapse_port_db
@@ -22,6 +22,7 @@ import logging
 import sys
 import time
 import traceback
+from typing import Dict, Optional, Set
 
 import yaml
 
@@ -39,6 +40,7 @@ from synapse.storage.database import DatabasePool, make_conn
 from synapse.storage.databases.main.client_ips import ClientIpBackgroundUpdateStore
 from synapse.storage.databases.main.deviceinbox import DeviceInboxBackgroundUpdateStore
 from synapse.storage.databases.main.devices import DeviceBackgroundUpdateStore
+from synapse.storage.databases.main.end_to_end_keys import EndToEndKeyBackgroundStore
 from synapse.storage.databases.main.events_bg_updates import (
     EventsBackgroundUpdatesStore,
 )
@@ -91,6 +93,7 @@ BOOLEAN_COLUMNS = {
     "room_stats_state": ["is_federatable"],
     "local_media_repository": ["safe_from_quarantine"],
     "users": ["shadow_banned"],
+    "e2e_fallback_keys_json": ["used"],
 }
 
 
@@ -152,7 +155,7 @@ IGNORED_TABLES = {
 
 # Error returned by the run function. Used at the top-level part of the script to
 # handle errors and return codes.
-end_error = None
+end_error = None  # type: Optional[str]
 # The exec_info for the error, if any. If error is defined but not exec_info the script
 # will show only the error message without the stacktrace, if exec_info is defined but
 # not the error then the script will show nothing outside of what's printed in the run
@@ -174,6 +177,7 @@ class Store(
     StateBackgroundUpdateStore,
     MainStateBackgroundUpdateStore,
     UserDirectoryBackgroundUpdateStore,
+    EndToEndKeyBackgroundStore,
     StatsStore,
 ):
     def execute(self, f, *args, **kwargs):
@@ -290,6 +294,34 @@ class Porter(object):
 
         return table, already_ported, total_to_port, forward_chunk, backward_chunk
 
+    async def get_table_constraints(self) -> Dict[str, Set[str]]:
+        """Returns a map of tables that have foreign key constraints to tables they depend on.
+        """
+
+        def _get_constraints(txn):
+            # We can pull the information about foreign key constraints out from
+            # the postgres schema tables.
+            sql = """
+                SELECT DISTINCT
+                    tc.table_name,
+                    ccu.table_name AS foreign_table_name
+                FROM
+                    information_schema.table_constraints AS tc
+                    INNER JOIN information_schema.constraint_column_usage AS ccu
+                    USING (table_schema, constraint_name)
+                WHERE tc.constraint_type = 'FOREIGN KEY';
+            """
+            txn.execute(sql)
+
+            results = {}
+            for table, foreign_table in txn:
+                results.setdefault(table, set()).add(foreign_table)
+            return results
+
+        return await self.postgres_store.db_pool.runInteraction(
+            "get_table_constraints", _get_constraints
+        )
+
     async def handle_table(
         self, table, postgres_size, table_size, forward_chunk, backward_chunk
     ):
@@ -491,7 +523,7 @@ class Porter(object):
 
         hs = MockHomeserver(self.hs_config)
 
-        with make_conn(db_config, engine) as db_conn:
+        with make_conn(db_config, engine, "portdb") as db_conn:
             engine.check_database(
                 db_conn, allow_outdated_version=allow_outdated_version
             )
@@ -589,7 +621,18 @@ class Porter(object):
                 "create_port_table", create_port_table
             )
 
-            # Step 2. Get tables.
+            # Step 2. Set up sequences
+            #
+            # We do this before porting the tables so that event if we fail half
+            # way through the postgres DB always have sequences that are greater
+            # than their respective tables. If we don't then creating the
+            # `DataStore` object will fail due to the inconsistency.
+            self.progress.set_state("Setting up sequence generators")
+            await self._setup_state_group_id_seq()
+            await self._setup_user_id_seq()
+            await self._setup_events_stream_seqs()
+
+            # Step 3. Get tables.
             self.progress.set_state("Fetching tables")
             sqlite_tables = await self.sqlite_store.db_pool.simple_select_onecol(
                 table="sqlite_master", keyvalues={"type": "table"}, retcol="name"
@@ -604,7 +647,7 @@ class Porter(object):
             tables = set(sqlite_tables) & set(postgres_tables)
             logger.info("Found %d tables", len(tables))
 
-            # Step 3. Figure out what still needs copying
+            # Step 4. Figure out what still needs copying
             self.progress.set_state("Checking on port progress")
             setup_res = await make_deferred_yieldable(
                 defer.gatherResults(
@@ -617,26 +660,48 @@ class Porter(object):
                     consumeErrors=True,
                 )
             )
+            # Map from table name to args passed to `handle_table`, i.e. a tuple
+            # of: `postgres_size`, `table_size`, `forward_chunk`, `backward_chunk`.
+            tables_to_port_info_map = {r[0]: r[1:] for r in setup_res}
 
-            # Step 4. Do the copying.
+            # Step 5. Do the copying.
+            #
+            # This is slightly convoluted as we need to ensure tables are ported
+            # in the correct order due to foreign key constraints.
             self.progress.set_state("Copying to postgres")
-            await make_deferred_yieldable(
-                defer.gatherResults(
-                    [run_in_background(self.handle_table, *res) for res in setup_res],
-                    consumeErrors=True,
-                )
-            )
 
-            # Step 5. Set up sequences
-            self.progress.set_state("Setting up sequence generators")
-            await self._setup_state_group_id_seq()
-            await self._setup_user_id_seq()
-            await self._setup_events_stream_seqs()
+            constraints = await self.get_table_constraints()
+            tables_ported = set()  # type: Set[str]
+
+            while tables_to_port_info_map:
+                # Pulls out all tables that are still to be ported and which
+                # only depend on tables that are already ported (if any).
+                tables_to_port = [
+                    table
+                    for table in tables_to_port_info_map
+                    if not constraints.get(table, set()) - tables_ported
+                ]
+
+                await make_deferred_yieldable(
+                    defer.gatherResults(
+                        [
+                            run_in_background(
+                                self.handle_table,
+                                table,
+                                *tables_to_port_info_map.pop(table),
+                            )
+                            for table in tables_to_port
+                        ],
+                        consumeErrors=True,
+                    )
+                )
+
+                tables_ported.update(tables_to_port)
 
             self.progress.done()
         except Exception as e:
             global end_error_exec_info
-            end_error = e
+            end_error = str(e)
             end_error_exec_info = sys.exc_info()
             logger.exception("")
         finally:
@@ -790,45 +855,62 @@ class Porter(object):
 
         return done, remaining + done
 
-    def _setup_state_group_id_seq(self):
+    async def _setup_state_group_id_seq(self):
+        curr_id = await self.sqlite_store.db_pool.simple_select_one_onecol(
+            table="state_groups", keyvalues={}, retcol="MAX(id)", allow_none=True
+        )
+
+        if not curr_id:
+            return
+
         def r(txn):
-            txn.execute("SELECT MAX(id) FROM state_groups")
-            curr_id = txn.fetchone()[0]
-            if not curr_id:
-                return
             next_id = curr_id + 1
             txn.execute("ALTER SEQUENCE state_group_id_seq RESTART WITH %s", (next_id,))
 
-        return self.postgres_store.db_pool.runInteraction("setup_state_group_id_seq", r)
+        await self.postgres_store.db_pool.runInteraction("setup_state_group_id_seq", r)
+
+    async def _setup_user_id_seq(self):
+        curr_id = await self.sqlite_store.db_pool.runInteraction(
+            "setup_user_id_seq", find_max_generated_user_id_localpart
+        )
 
-    def _setup_user_id_seq(self):
         def r(txn):
-            next_id = find_max_generated_user_id_localpart(txn) + 1
+            next_id = curr_id + 1
             txn.execute("ALTER SEQUENCE user_id_seq RESTART WITH %s", (next_id,))
 
         return self.postgres_store.db_pool.runInteraction("setup_user_id_seq", r)
 
-    def _setup_events_stream_seqs(self):
-        def r(txn):
-            txn.execute("SELECT MAX(stream_ordering) FROM events")
-            curr_id = txn.fetchone()[0]
-            if curr_id:
-                next_id = curr_id + 1
+    async def _setup_events_stream_seqs(self):
+        """Set the event stream sequences to the correct values.
+        """
+
+        # We get called before we've ported the events table, so we need to
+        # fetch the current positions from the SQLite store.
+        curr_forward_id = await self.sqlite_store.db_pool.simple_select_one_onecol(
+            table="events", keyvalues={}, retcol="MAX(stream_ordering)", allow_none=True
+        )
+
+        curr_backward_id = await self.sqlite_store.db_pool.simple_select_one_onecol(
+            table="events",
+            keyvalues={},
+            retcol="MAX(-MIN(stream_ordering), 1)",
+            allow_none=True,
+        )
+
+        def _setup_events_stream_seqs_set_pos(txn):
+            if curr_forward_id:
                 txn.execute(
-                    "ALTER SEQUENCE events_stream_seq RESTART WITH %s", (next_id,)
+                    "ALTER SEQUENCE events_stream_seq RESTART WITH %s",
+                    (curr_forward_id + 1,),
                 )
 
-            txn.execute("SELECT -MIN(stream_ordering) FROM events")
-            curr_id = txn.fetchone()[0]
-            if curr_id:
-                next_id = curr_id + 1
-                txn.execute(
-                    "ALTER SEQUENCE events_backfill_stream_seq RESTART WITH %s",
-                    (next_id,),
-                )
+            txn.execute(
+                "ALTER SEQUENCE events_backfill_stream_seq RESTART WITH %s",
+                (curr_backward_id + 1,),
+            )
 
-        return self.postgres_store.db_pool.runInteraction(
-            "_setup_events_stream_seqs", r
+        return await self.postgres_store.db_pool.runInteraction(
+            "_setup_events_stream_seqs", _setup_events_stream_seqs_set_pos,
         )
 
 
diff --git a/setup.cfg b/setup.cfg
index a32278ea8a..f46e43fad0 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,8 +1,3 @@
-[build_sphinx]
-source-dir = docs/sphinx
-build-dir  = docs/build
-all_files  = 1
-
 [trial]
 test_suite = tests
 
diff --git a/setup.py b/setup.py
index 926b1bc86f..9730afb41b 100755
--- a/setup.py
+++ b/setup.py
@@ -15,12 +15,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import glob
 import os
-from setuptools import setup, find_packages, Command
-import sys
 
+from setuptools import Command, find_packages, setup
 
 here = os.path.abspath(os.path.dirname(__file__))
 
@@ -104,6 +102,8 @@ CONDITIONAL_REQUIREMENTS["lint"] = [
     "flake8",
 ]
 
+CONDITIONAL_REQUIREMENTS["mypy"] = ["mypy==0.790", "mypy-zope==0.2.8"]
+
 # Dependencies which are exclusively required by unit test code. This is
 # NOT a list of all modules that are necessary to run the unit tests.
 # Tests assume that all optional dependencies are installed.
@@ -131,6 +131,7 @@ setup(
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
     ],
     scripts=["synctl"] + glob.glob("scripts/*"),
     cmdclass={"test": TestCommand},
diff --git a/stubs/sortedcontainers/__init__.pyi b/stubs/sortedcontainers/__init__.pyi
index 073b806d3c..fa307483fe 100644
--- a/stubs/sortedcontainers/__init__.pyi
+++ b/stubs/sortedcontainers/__init__.pyi
@@ -1,13 +1,12 @@
-from .sorteddict import (
-    SortedDict,
-    SortedKeysView,
-    SortedItemsView,
-    SortedValuesView,
-)
+from .sorteddict import SortedDict, SortedItemsView, SortedKeysView, SortedValuesView
+from .sortedlist import SortedKeyList, SortedList, SortedListWithKey
 
 __all__ = [
     "SortedDict",
     "SortedKeysView",
     "SortedItemsView",
     "SortedValuesView",
+    "SortedKeyList",
+    "SortedList",
+    "SortedListWithKey",
 ]
diff --git a/stubs/sortedcontainers/sortedlist.pyi b/stubs/sortedcontainers/sortedlist.pyi
new file mode 100644
index 0000000000..8f6086b3ff
--- /dev/null
+++ b/stubs/sortedcontainers/sortedlist.pyi
@@ -0,0 +1,177 @@
+# stub for SortedList. This is an exact copy of
+# https://github.com/grantjenks/python-sortedcontainers/blob/a419ffbd2b1c935b09f11f0971696e537fd0c510/sortedcontainers/sortedlist.pyi
+# (from https://github.com/grantjenks/python-sortedcontainers/pull/107)
+
+from typing import (
+    Any,
+    Callable,
+    Generic,
+    Iterable,
+    Iterator,
+    List,
+    MutableSequence,
+    Optional,
+    Sequence,
+    Tuple,
+    Type,
+    TypeVar,
+    Union,
+    overload,
+)
+
+_T = TypeVar("_T")
+_SL = TypeVar("_SL", bound=SortedList)
+_SKL = TypeVar("_SKL", bound=SortedKeyList)
+_Key = Callable[[_T], Any]
+_Repr = Callable[[], str]
+
+def recursive_repr(fillvalue: str = ...) -> Callable[[_Repr], _Repr]: ...
+
+class SortedList(MutableSequence[_T]):
+
+    DEFAULT_LOAD_FACTOR: int = ...
+    def __init__(
+        self, iterable: Optional[Iterable[_T]] = ..., key: Optional[_Key[_T]] = ...,
+    ): ...
+    # NB: currently mypy does not honour return type, see mypy #3307
+    @overload
+    def __new__(cls: Type[_SL], iterable: None, key: None) -> _SL: ...
+    @overload
+    def __new__(cls: Type[_SL], iterable: None, key: _Key[_T]) -> SortedKeyList[_T]: ...
+    @overload
+    def __new__(cls: Type[_SL], iterable: Iterable[_T], key: None) -> _SL: ...
+    @overload
+    def __new__(cls, iterable: Iterable[_T], key: _Key[_T]) -> SortedKeyList[_T]: ...
+    @property
+    def key(self) -> Optional[Callable[[_T], Any]]: ...
+    def _reset(self, load: int) -> None: ...
+    def clear(self) -> None: ...
+    def _clear(self) -> None: ...
+    def add(self, value: _T) -> None: ...
+    def _expand(self, pos: int) -> None: ...
+    def update(self, iterable: Iterable[_T]) -> None: ...
+    def _update(self, iterable: Iterable[_T]) -> None: ...
+    def discard(self, value: _T) -> None: ...
+    def remove(self, value: _T) -> None: ...
+    def _delete(self, pos: int, idx: int) -> None: ...
+    def _loc(self, pos: int, idx: int) -> int: ...
+    def _pos(self, idx: int) -> int: ...
+    def _build_index(self) -> None: ...
+    def __contains__(self, value: Any) -> bool: ...
+    def __delitem__(self, index: Union[int, slice]) -> None: ...
+    @overload
+    def __getitem__(self, index: int) -> _T: ...
+    @overload
+    def __getitem__(self, index: slice) -> List[_T]: ...
+    @overload
+    def _getitem(self, index: int) -> _T: ...
+    @overload
+    def _getitem(self, index: slice) -> List[_T]: ...
+    @overload
+    def __setitem__(self, index: int, value: _T) -> None: ...
+    @overload
+    def __setitem__(self, index: slice, value: Iterable[_T]) -> None: ...
+    def __iter__(self) -> Iterator[_T]: ...
+    def __reversed__(self) -> Iterator[_T]: ...
+    def __len__(self) -> int: ...
+    def reverse(self) -> None: ...
+    def islice(
+        self, start: Optional[int] = ..., stop: Optional[int] = ..., reverse=bool,
+    ) -> Iterator[_T]: ...
+    def _islice(
+        self, min_pos: int, min_idx: int, max_pos: int, max_idx: int, reverse: bool,
+    ) -> Iterator[_T]: ...
+    def irange(
+        self,
+        minimum: Optional[int] = ...,
+        maximum: Optional[int] = ...,
+        inclusive: Tuple[bool, bool] = ...,
+        reverse: bool = ...,
+    ) -> Iterator[_T]: ...
+    def bisect_left(self, value: _T) -> int: ...
+    def bisect_right(self, value: _T) -> int: ...
+    def bisect(self, value: _T) -> int: ...
+    def _bisect_right(self, value: _T) -> int: ...
+    def count(self, value: _T) -> int: ...
+    def copy(self: _SL) -> _SL: ...
+    def __copy__(self: _SL) -> _SL: ...
+    def append(self, value: _T) -> None: ...
+    def extend(self, values: Iterable[_T]) -> None: ...
+    def insert(self, index: int, value: _T) -> None: ...
+    def pop(self, index: int = ...) -> _T: ...
+    def index(
+        self, value: _T, start: Optional[int] = ..., stop: Optional[int] = ...
+    ) -> int: ...
+    def __add__(self: _SL, other: Iterable[_T]) -> _SL: ...
+    def __radd__(self: _SL, other: Iterable[_T]) -> _SL: ...
+    def __iadd__(self: _SL, other: Iterable[_T]) -> _SL: ...
+    def __mul__(self: _SL, num: int) -> _SL: ...
+    def __rmul__(self: _SL, num: int) -> _SL: ...
+    def __imul__(self: _SL, num: int) -> _SL: ...
+    def __eq__(self, other: Any) -> bool: ...
+    def __ne__(self, other: Any) -> bool: ...
+    def __lt__(self, other: Sequence[_T]) -> bool: ...
+    def __gt__(self, other: Sequence[_T]) -> bool: ...
+    def __le__(self, other: Sequence[_T]) -> bool: ...
+    def __ge__(self, other: Sequence[_T]) -> bool: ...
+    def __repr__(self) -> str: ...
+    def _check(self) -> None: ...
+
+class SortedKeyList(SortedList[_T]):
+    def __init__(
+        self, iterable: Optional[Iterable[_T]] = ..., key: _Key[_T] = ...
+    ) -> None: ...
+    def __new__(
+        cls, iterable: Optional[Iterable[_T]] = ..., key: _Key[_T] = ...
+    ) -> SortedKeyList[_T]: ...
+    @property
+    def key(self) -> Callable[[_T], Any]: ...
+    def clear(self) -> None: ...
+    def _clear(self) -> None: ...
+    def add(self, value: _T) -> None: ...
+    def _expand(self, pos: int) -> None: ...
+    def update(self, iterable: Iterable[_T]) -> None: ...
+    def _update(self, iterable: Iterable[_T]) -> None: ...
+    # NB: Must be T to be safely passed to self.func, yet base class imposes Any
+    def __contains__(self, value: _T) -> bool: ...  # type: ignore
+    def discard(self, value: _T) -> None: ...
+    def remove(self, value: _T) -> None: ...
+    def _delete(self, pos: int, idx: int) -> None: ...
+    def irange(
+        self,
+        minimum: Optional[int] = ...,
+        maximum: Optional[int] = ...,
+        inclusive: Tuple[bool, bool] = ...,
+        reverse: bool = ...,
+    ): ...
+    def irange_key(
+        self,
+        min_key: Optional[Any] = ...,
+        max_key: Optional[Any] = ...,
+        inclusive: Tuple[bool, bool] = ...,
+        reserve: bool = ...,
+    ): ...
+    def bisect_left(self, value: _T) -> int: ...
+    def bisect_right(self, value: _T) -> int: ...
+    def bisect(self, value: _T) -> int: ...
+    def bisect_key_left(self, key: Any) -> int: ...
+    def _bisect_key_left(self, key: Any) -> int: ...
+    def bisect_key_right(self, key: Any) -> int: ...
+    def _bisect_key_right(self, key: Any) -> int: ...
+    def bisect_key(self, key: Any) -> int: ...
+    def count(self, value: _T) -> int: ...
+    def copy(self: _SKL) -> _SKL: ...
+    def __copy__(self: _SKL) -> _SKL: ...
+    def index(
+        self, value: _T, start: Optional[int] = ..., stop: Optional[int] = ...
+    ) -> int: ...
+    def __add__(self: _SKL, other: Iterable[_T]) -> _SKL: ...
+    def __radd__(self: _SKL, other: Iterable[_T]) -> _SKL: ...
+    def __iadd__(self: _SKL, other: Iterable[_T]) -> _SKL: ...
+    def __mul__(self: _SKL, num: int) -> _SKL: ...
+    def __rmul__(self: _SKL, num: int) -> _SKL: ...
+    def __imul__(self: _SKL, num: int) -> _SKL: ...
+    def __repr__(self) -> str: ...
+    def _check(self) -> None: ...
+
+SortedListWithKey = SortedKeyList
diff --git a/stubs/txredisapi.pyi b/stubs/txredisapi.pyi
index c66413f003..522244bb57 100644
--- a/stubs/txredisapi.pyi
+++ b/stubs/txredisapi.pyi
@@ -16,7 +16,7 @@
 """Contains *incomplete* type hints for txredisapi.
 """
 
-from typing import List, Optional, Union
+from typing import List, Optional, Union, Type
 
 class RedisProtocol:
     def publish(self, channel: str, message: bytes): ...
@@ -42,3 +42,21 @@ def lazyConnection(
 
 class SubscriberFactory:
     def buildProtocol(self, addr): ...
+
+class ConnectionHandler: ...
+
+class RedisFactory:
+    continueTrying: bool
+    handler: RedisProtocol
+    def __init__(
+        self,
+        uuid: str,
+        dbid: Optional[int],
+        poolsize: int,
+        isLazy: bool = False,
+        handler: Type = ConnectionHandler,
+        charset: str = "utf-8",
+        password: Optional[str] = None,
+        replyTimeout: Optional[int] = None,
+        convertNumbers: Optional[int] = True,
+    ): ...
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 83b8e4897f..f2d3ac68eb 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -48,7 +48,7 @@ try:
 except ImportError:
     pass
 
-__version__ = "1.21.2"
+__version__ = "1.24.0"
 
 if bool(os.environ.get("SYNAPSE_TEST_PATCH_LOG_CONTEXTS", False)):
     # We import here so that we don't have to install a bunch of deps when
diff --git a/synapse/_scripts/register_new_matrix_user.py b/synapse/_scripts/register_new_matrix_user.py
index da0996edbc..dfe26dea6d 100644
--- a/synapse/_scripts/register_new_matrix_user.py
+++ b/synapse/_scripts/register_new_matrix_user.py
@@ -37,7 +37,7 @@ def request_registration(
     exit=sys.exit,
 ):
 
-    url = "%s/_matrix/client/r0/admin/register" % (server_location,)
+    url = "%s/_synapse/admin/v1/register" % (server_location.rstrip("/"),)
 
     # Get the nonce
     r = requests.get(url, verify=False)
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 37668bc42a..bc73982dc2 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -33,8 +33,8 @@ from synapse.api.errors import (
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.events import EventBase
 from synapse.logging import opentracing as opentracing
+from synapse.storage.databases.main.registration import TokenLookupResult
 from synapse.types import StateMap, UserID
-from synapse.util.caches import register_cache
 from synapse.util.caches.lrucache import LruCache
 from synapse.util.metrics import Measure
 
@@ -70,8 +70,9 @@ class Auth:
         self.store = hs.get_datastore()
         self.state = hs.get_state_handler()
 
-        self.token_cache = LruCache(10000)
-        register_cache("cache", "token_cache", self.token_cache)
+        self.token_cache = LruCache(
+            10000, "token_cache"
+        )  # type: LruCache[str, Tuple[str, bool]]
 
         self._auth_blocking = AuthBlocking(self.hs)
 
@@ -184,18 +185,12 @@ class Auth:
         """
         try:
             ip_addr = self.hs.get_ip_from_request(request)
-            user_agent = request.requestHeaders.getRawHeaders(
-                b"User-Agent", default=[b""]
-            )[0].decode("ascii", "surrogateescape")
+            user_agent = request.get_user_agent("")
 
             access_token = self.get_access_token_from_request(request)
 
             user_id, app_service = self._get_appservice_user_id(request)
             if user_id:
-                request.authenticated_entity = user_id
-                opentracing.set_tag("authenticated_entity", user_id)
-                opentracing.set_tag("appservice_id", app_service.id)
-
                 if ip_addr and self._track_appservice_user_ips:
                     await self.store.insert_client_ip(
                         user_id=user_id,
@@ -205,31 +200,38 @@ class Auth:
                         device_id="dummy-device",  # stubbed
                     )
 
-                return synapse.types.create_requester(user_id, app_service=app_service)
+                requester = synapse.types.create_requester(
+                    user_id, app_service=app_service
+                )
+
+                request.requester = user_id
+                opentracing.set_tag("authenticated_entity", user_id)
+                opentracing.set_tag("user_id", user_id)
+                opentracing.set_tag("appservice_id", app_service.id)
+
+                return requester
 
             user_info = await self.get_user_by_access_token(
                 access_token, rights, allow_expired=allow_expired
             )
-            user = user_info["user"]
-            token_id = user_info["token_id"]
-            is_guest = user_info["is_guest"]
-            shadow_banned = user_info["shadow_banned"]
+            token_id = user_info.token_id
+            is_guest = user_info.is_guest
+            shadow_banned = user_info.shadow_banned
 
             # Deny the request if the user account has expired.
             if self._account_validity_enabled and not allow_expired:
-                user_id = user.to_string()
-                if await self.store.is_account_expired(user_id, self.clock.time_msec()):
+                if await self.store.is_account_expired(
+                    user_info.user_id, self.clock.time_msec()
+                ):
                     raise AuthError(
                         403, "User account has expired", errcode=Codes.EXPIRED_ACCOUNT
                     )
 
-            # device_id may not be present if get_user_by_access_token has been
-            # stubbed out.
-            device_id = user_info.get("device_id")
+            device_id = user_info.device_id
 
-            if user and access_token and ip_addr:
+            if access_token and ip_addr:
                 await self.store.insert_client_ip(
-                    user_id=user.to_string(),
+                    user_id=user_info.token_owner,
                     access_token=access_token,
                     ip=ip_addr,
                     user_agent=user_agent,
@@ -243,19 +245,23 @@ class Auth:
                     errcode=Codes.GUEST_ACCESS_FORBIDDEN,
                 )
 
-            request.authenticated_entity = user.to_string()
-            opentracing.set_tag("authenticated_entity", user.to_string())
-            if device_id:
-                opentracing.set_tag("device_id", device_id)
-
-            return synapse.types.create_requester(
-                user,
+            requester = synapse.types.create_requester(
+                user_info.user_id,
                 token_id,
                 is_guest,
                 shadow_banned,
                 device_id,
                 app_service=app_service,
+                authenticated_entity=user_info.token_owner,
             )
+
+            request.requester = requester
+            opentracing.set_tag("authenticated_entity", user_info.token_owner)
+            opentracing.set_tag("user_id", user_info.user_id)
+            if device_id:
+                opentracing.set_tag("device_id", device_id)
+
+            return requester
         except KeyError:
             raise MissingClientTokenError()
 
@@ -291,7 +297,7 @@ class Auth:
 
     async def get_user_by_access_token(
         self, token: str, rights: str = "access", allow_expired: bool = False,
-    ) -> dict:
+    ) -> TokenLookupResult:
         """ Validate access token and get user_id from it
 
         Args:
@@ -300,13 +306,7 @@ class Auth:
                 allow this
             allow_expired: If False, raises an InvalidClientTokenError
                 if the token is expired
-        Returns:
-            dict that includes:
-               `user` (UserID)
-               `is_guest` (bool)
-               `shadow_banned` (bool)
-               `token_id` (int|None): access token id. May be None if guest
-               `device_id` (str|None): device corresponding to access token
+
         Raises:
             InvalidClientTokenError if a user by that token exists, but the token is
                 expired
@@ -316,9 +316,9 @@ class Auth:
 
         if rights == "access":
             # first look in the database
-            r = await self._look_up_user_by_access_token(token)
+            r = await self.store.get_user_by_access_token(token)
             if r:
-                valid_until_ms = r["valid_until_ms"]
+                valid_until_ms = r.valid_until_ms
                 if (
                     not allow_expired
                     and valid_until_ms is not None
@@ -335,7 +335,6 @@ class Auth:
         # otherwise it needs to be a valid macaroon
         try:
             user_id, guest = self._parse_and_validate_macaroon(token, rights)
-            user = UserID.from_string(user_id)
 
             if rights == "access":
                 if not guest:
@@ -361,23 +360,17 @@ class Auth:
                     raise InvalidClientTokenError(
                         "Guest access token used for regular user"
                     )
-                ret = {
-                    "user": user,
-                    "is_guest": True,
-                    "shadow_banned": False,
-                    "token_id": None,
+
+                ret = TokenLookupResult(
+                    user_id=user_id,
+                    is_guest=True,
                     # all guests get the same device id
-                    "device_id": GUEST_DEVICE_ID,
-                }
+                    device_id=GUEST_DEVICE_ID,
+                )
             elif rights == "delete_pusher":
                 # We don't store these tokens in the database
-                ret = {
-                    "user": user,
-                    "is_guest": False,
-                    "shadow_banned": False,
-                    "token_id": None,
-                    "device_id": None,
-                }
+
+                ret = TokenLookupResult(user_id=user_id, is_guest=False)
             else:
                 raise RuntimeError("Unknown rights setting %s", rights)
             return ret
@@ -486,31 +479,15 @@ class Auth:
         now = self.hs.get_clock().time_msec()
         return now < expiry
 
-    async def _look_up_user_by_access_token(self, token):
-        ret = await self.store.get_user_by_access_token(token)
-        if not ret:
-            return None
-
-        # we use ret.get() below because *lots* of unit tests stub out
-        # get_user_by_access_token in a way where it only returns a couple of
-        # the fields.
-        user_info = {
-            "user": UserID.from_string(ret.get("name")),
-            "token_id": ret.get("token_id", None),
-            "is_guest": False,
-            "shadow_banned": ret.get("shadow_banned"),
-            "device_id": ret.get("device_id"),
-            "valid_until_ms": ret.get("valid_until_ms"),
-        }
-        return user_info
-
     def get_appservice_by_req(self, request):
         token = self.get_access_token_from_request(request)
         service = self.store.get_app_service_by_token(token)
         if not service:
             logger.warning("Unrecognised appservice access token.")
             raise InvalidClientTokenError()
-        request.authenticated_entity = service.sender
+        request.requester = synapse.types.create_requester(
+            service.sender, app_service=service
+        )
         return service
 
     async def is_server_admin(self, user: UserID) -> bool:
diff --git a/synapse/api/auth_blocking.py b/synapse/api/auth_blocking.py
index d8fafd7cb8..9c227218e0 100644
--- a/synapse/api/auth_blocking.py
+++ b/synapse/api/auth_blocking.py
@@ -14,10 +14,12 @@
 # limitations under the License.
 
 import logging
+from typing import Optional
 
 from synapse.api.constants import LimitBlockingTypes, UserTypes
 from synapse.api.errors import Codes, ResourceLimitError
 from synapse.config.server import is_threepid_reserved
+from synapse.types import Requester
 
 logger = logging.getLogger(__name__)
 
@@ -33,24 +35,47 @@ class AuthBlocking:
         self._max_mau_value = hs.config.max_mau_value
         self._limit_usage_by_mau = hs.config.limit_usage_by_mau
         self._mau_limits_reserved_threepids = hs.config.mau_limits_reserved_threepids
+        self._server_name = hs.hostname
 
-    async def check_auth_blocking(self, user_id=None, threepid=None, user_type=None):
+    async def check_auth_blocking(
+        self,
+        user_id: Optional[str] = None,
+        threepid: Optional[dict] = None,
+        user_type: Optional[str] = None,
+        requester: Optional[Requester] = None,
+    ):
         """Checks if the user should be rejected for some external reason,
         such as monthly active user limiting or global disable flag
 
         Args:
-            user_id(str|None): If present, checks for presence against existing
+            user_id: If present, checks for presence against existing
                 MAU cohort
 
-            threepid(dict|None): If present, checks for presence against configured
+            threepid: If present, checks for presence against configured
                 reserved threepid. Used in cases where the user is trying register
                 with a MAU blocked server, normally they would be rejected but their
                 threepid is on the reserved list. user_id and
                 threepid should never be set at the same time.
 
-            user_type(str|None): If present, is used to decide whether to check against
+            user_type: If present, is used to decide whether to check against
                 certain blocking reasons like MAU.
+
+            requester: If present, and the authenticated entity is a user, checks for
+                presence against existing MAU cohort. Passing in both a `user_id` and
+                `requester` is an error.
         """
+        if requester and user_id:
+            raise Exception(
+                "Passed in both 'user_id' and 'requester' to 'check_auth_blocking'"
+            )
+
+        if requester:
+            if requester.authenticated_entity.startswith("@"):
+                user_id = requester.authenticated_entity
+            elif requester.authenticated_entity == self._server_name:
+                # We never block the server from doing actions on behalf of
+                # users.
+                return
 
         # Never fail an auth check for the server notices users or support user
         # This can be a problem where event creation is prohibited due to blocking
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 46013cde15..592abd844b 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -155,3 +155,8 @@ class EventContentFields:
 class RoomEncryptionAlgorithms:
     MEGOLM_V1_AES_SHA2 = "m.megolm.v1.aes-sha2"
     DEFAULT = MEGOLM_V1_AES_SHA2
+
+
+class AccountDataTypes:
+    DIRECT = "m.direct"
+    IGNORED_USER_LIST = "m.ignored_user_list"
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index fb476ddaf5..895b38ae76 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -28,9 +28,11 @@ from twisted.protocols.tls import TLSMemoryBIOFactory
 
 import synapse
 from synapse.app import check_bind_error
+from synapse.app.phone_stats_home import start_phone_stats_home
 from synapse.config.server import ListenerConfig
 from synapse.crypto import context_factory
 from synapse.logging.context import PreserveLoggingContext
+from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.util.async_helpers import Linearizer
 from synapse.util.daemonize import daemonize_process
 from synapse.util.rlimit import change_resource_limit
@@ -48,7 +50,6 @@ def register_sighup(func, *args, **kwargs):
 
     Args:
         func (function): Function to be called when sent a SIGHUP signal.
-            Will be called with a single default argument, the homeserver.
         *args, **kwargs: args and kwargs to be passed to the target function.
     """
     _sighup_callbacks.append((func, args, kwargs))
@@ -244,19 +245,26 @@ def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]):
         # Set up the SIGHUP machinery.
         if hasattr(signal, "SIGHUP"):
 
+            @wrap_as_background_process("sighup")
             def handle_sighup(*args, **kwargs):
                 # Tell systemd our state, if we're using it. This will silently fail if
                 # we're not using systemd.
                 sdnotify(b"RELOADING=1")
 
                 for i, args, kwargs in _sighup_callbacks:
-                    i(hs, *args, **kwargs)
+                    i(*args, **kwargs)
 
                 sdnotify(b"READY=1")
 
-            signal.signal(signal.SIGHUP, handle_sighup)
+            # We defer running the sighup handlers until next reactor tick. This
+            # is so that we're in a sane state, e.g. flushing the logs may fail
+            # if the sighup happens in the middle of writing a log entry.
+            def run_sighup(*args, **kwargs):
+                hs.get_clock().call_later(0, handle_sighup, *args, **kwargs)
 
-            register_sighup(refresh_certificate)
+            signal.signal(signal.SIGHUP, run_sighup)
+
+            register_sighup(refresh_certificate, hs)
 
         # Load the certificate from disk.
         refresh_certificate(hs)
@@ -271,9 +279,19 @@ def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]):
         hs.get_datastore().db_pool.start_profiling()
         hs.get_pusherpool().start()
 
+        # Log when we start the shut down process.
+        hs.get_reactor().addSystemEventTrigger(
+            "before", "shutdown", logger.info, "Shutting down..."
+        )
+
         setup_sentry(hs)
         setup_sdnotify(hs)
 
+        # If background tasks are running on the main process, start collecting the
+        # phone home stats.
+        if hs.config.run_background_tasks:
+            start_phone_stats_home(hs)
+
         # We now freeze all allocated objects in the hopes that (almost)
         # everything currently allocated are things that will be used for the
         # rest of time. Doing so means less work each GC (hopefully).
diff --git a/synapse/app/admin_cmd.py b/synapse/app/admin_cmd.py
index 7d309b1bb0..b4bd4d8e7a 100644
--- a/synapse/app/admin_cmd.py
+++ b/synapse/app/admin_cmd.py
@@ -89,7 +89,7 @@ async def export_data_command(hs, args):
     user_id = args.user_id
     directory = args.output_directory
 
-    res = await hs.get_handlers().admin_handler.export_user_data(
+    res = await hs.get_admin_handler().export_user_data(
         user_id, FileExfiltrationWriter(user_id, directory=directory)
     )
     print(res)
@@ -208,6 +208,7 @@ def start(config_options):
 
     # Explicitly disable background processes
     config.update_user_directory = False
+    config.run_background_tasks = False
     config.start_pushers = False
     config.send_federation = False
 
diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py
index 15312ef961..e3595a19d1 100644
--- a/synapse/app/generic_worker.py
+++ b/synapse/app/generic_worker.py
@@ -127,12 +127,16 @@ from synapse.rest.health import HealthResource
 from synapse.rest.key.v2 import KeyApiV2Resource
 from synapse.server import HomeServer, cache_in_self
 from synapse.storage.databases.main.censor_events import CensorEventsStore
+from synapse.storage.databases.main.client_ips import ClientIpWorkerStore
 from synapse.storage.databases.main.media_repository import MediaRepositoryStore
+from synapse.storage.databases.main.metrics import ServerMetricsStore
 from synapse.storage.databases.main.monthly_active_users import (
     MonthlyActiveUsersWorkerStore,
 )
 from synapse.storage.databases.main.presence import UserPresenceState
 from synapse.storage.databases.main.search import SearchWorkerStore
+from synapse.storage.databases.main.stats import StatsStore
+from synapse.storage.databases.main.transactions import TransactionWorkerStore
 from synapse.storage.databases.main.ui_auth import UIAuthWorkerStore
 from synapse.storage.databases.main.user_directory import UserDirectoryStore
 from synapse.types import ReadReceipt
@@ -454,6 +458,7 @@ class GenericWorkerSlavedStore(
     # FIXME(#3714): We need to add UserDirectoryStore as we write directly
     # rather than going via the correct worker.
     UserDirectoryStore,
+    StatsStore,
     UIAuthWorkerStore,
     SlavedDeviceInboxStore,
     SlavedDeviceStore,
@@ -463,6 +468,7 @@ class GenericWorkerSlavedStore(
     SlavedAccountDataStore,
     SlavedPusherStore,
     CensorEventsStore,
+    ClientIpWorkerStore,
     SlavedEventStore,
     SlavedKeyStore,
     RoomStore,
@@ -476,7 +482,9 @@ class GenericWorkerSlavedStore(
     SlavedFilteringStore,
     MonthlyActiveUsersWorkerStore,
     MediaRepositoryStore,
+    ServerMetricsStore,
     SearchWorkerStore,
+    TransactionWorkerStore,
     BaseSlavedStore,
 ):
     pass
@@ -782,10 +790,6 @@ class FederationSenderHandler:
             send_queue.process_rows_for_federation(self.federation_sender, rows)
             await self.update_token(token)
 
-        # We also need to poke the federation sender when new events happen
-        elif stream_name == "events":
-            self.federation_sender.notify_new_events(token)
-
         # ... and when new receipts happen
         elif stream_name == ReceiptsStream.NAME:
             await self._on_new_receipts(rows)
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index dff739e106..2b5465417f 100644
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -17,14 +17,10 @@
 
 import gc
 import logging
-import math
 import os
-import resource
 import sys
 from typing import Iterable
 
-from prometheus_client import Gauge
-
 from twisted.application import service
 from twisted.internet import defer, reactor
 from twisted.python.failure import Failure
@@ -60,8 +56,6 @@ from synapse.http.server import (
 from synapse.http.site import SynapseSite
 from synapse.logging.context import LoggingContext
 from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.module_api import ModuleApi
 from synapse.python_dependencies import check_requirements
 from synapse.replication.http import REPLICATION_PREFIX, ReplicationRestResource
 from synapse.replication.tcp.resource import ReplicationStreamProtocolFactory
@@ -111,7 +105,7 @@ class SynapseHomeServer(HomeServer):
 
         additional_resources = listener_config.http_options.additional_resources
         logger.debug("Configuring additional resources: %r", additional_resources)
-        module_api = ModuleApi(self, self.get_auth_handler())
+        module_api = self.get_module_api()
         for path, resmodule in additional_resources.items():
             handler_cls, config = load_module(resmodule)
             handler = handler_cls(config, module_api)
@@ -334,20 +328,6 @@ class SynapseHomeServer(HomeServer):
                 logger.warning("Unrecognized listener type: %s", listener.type)
 
 
-# Gauges to expose monthly active user control metrics
-current_mau_gauge = Gauge("synapse_admin_mau:current", "Current MAU")
-current_mau_by_service_gauge = Gauge(
-    "synapse_admin_mau_current_mau_by_service",
-    "Current MAU by service",
-    ["app_service"],
-)
-max_mau_gauge = Gauge("synapse_admin_mau:max", "MAU Limit")
-registered_reserved_users_mau_gauge = Gauge(
-    "synapse_admin_mau:registered_reserved_users",
-    "Registered users with reserved threepids",
-)
-
-
 def setup(config_options):
     """
     Args:
@@ -389,8 +369,6 @@ def setup(config_options):
     except UpgradeDatabaseException as e:
         quit_with_error("Failed to upgrade database: %s" % (e,))
 
-    hs.setup_master()
-
     async def do_acme() -> bool:
         """
         Reprovision an ACME certificate, if it's required.
@@ -486,92 +464,6 @@ class SynapseService(service.Service):
         return self._port.stopListening()
 
 
-# Contains the list of processes we will be monitoring
-# currently either 0 or 1
-_stats_process = []
-
-
-async def phone_stats_home(hs, stats, stats_process=_stats_process):
-    logger.info("Gathering stats for reporting")
-    now = int(hs.get_clock().time())
-    uptime = int(now - hs.start_time)
-    if uptime < 0:
-        uptime = 0
-
-    #
-    # Performance statistics. Keep this early in the function to maintain reliability of `test_performance_100` test.
-    #
-    old = stats_process[0]
-    new = (now, resource.getrusage(resource.RUSAGE_SELF))
-    stats_process[0] = new
-
-    # Get RSS in bytes
-    stats["memory_rss"] = new[1].ru_maxrss
-
-    # Get CPU time in % of a single core, not % of all cores
-    used_cpu_time = (new[1].ru_utime + new[1].ru_stime) - (
-        old[1].ru_utime + old[1].ru_stime
-    )
-    if used_cpu_time == 0 or new[0] == old[0]:
-        stats["cpu_average"] = 0
-    else:
-        stats["cpu_average"] = math.floor(used_cpu_time / (new[0] - old[0]) * 100)
-
-    #
-    # General statistics
-    #
-
-    stats["homeserver"] = hs.config.server_name
-    stats["server_context"] = hs.config.server_context
-    stats["timestamp"] = now
-    stats["uptime_seconds"] = uptime
-    version = sys.version_info
-    stats["python_version"] = "{}.{}.{}".format(
-        version.major, version.minor, version.micro
-    )
-    stats["total_users"] = await hs.get_datastore().count_all_users()
-
-    total_nonbridged_users = await hs.get_datastore().count_nonbridged_users()
-    stats["total_nonbridged_users"] = total_nonbridged_users
-
-    daily_user_type_results = await hs.get_datastore().count_daily_user_type()
-    for name, count in daily_user_type_results.items():
-        stats["daily_user_type_" + name] = count
-
-    room_count = await hs.get_datastore().get_room_count()
-    stats["total_room_count"] = room_count
-
-    stats["daily_active_users"] = await hs.get_datastore().count_daily_users()
-    stats["monthly_active_users"] = await hs.get_datastore().count_monthly_users()
-    stats["daily_active_rooms"] = await hs.get_datastore().count_daily_active_rooms()
-    stats["daily_messages"] = await hs.get_datastore().count_daily_messages()
-
-    r30_results = await hs.get_datastore().count_r30_users()
-    for name, count in r30_results.items():
-        stats["r30_users_" + name] = count
-
-    daily_sent_messages = await hs.get_datastore().count_daily_sent_messages()
-    stats["daily_sent_messages"] = daily_sent_messages
-    stats["cache_factor"] = hs.config.caches.global_factor
-    stats["event_cache_size"] = hs.config.caches.event_cache_size
-
-    #
-    # Database version
-    #
-
-    # This only reports info about the *main* database.
-    stats["database_engine"] = hs.get_datastore().db_pool.engine.module.__name__
-    stats["database_server_version"] = hs.get_datastore().db_pool.engine.server_version
-
-    logger.info("Reporting stats to %s: %s" % (hs.config.report_stats_endpoint, stats))
-    try:
-        await hs.get_proxied_http_client().put_json(
-            hs.config.report_stats_endpoint, stats
-        )
-    except Exception as e:
-        logger.warning("Error reporting stats: %s", e)
-
-
 def run(hs):
     PROFILE_SYNAPSE = False
     if PROFILE_SYNAPSE:
@@ -597,81 +489,6 @@ def run(hs):
         ThreadPool._worker = profile(ThreadPool._worker)
         reactor.run = profile(reactor.run)
 
-    clock = hs.get_clock()
-
-    stats = {}
-
-    def performance_stats_init():
-        _stats_process.clear()
-        _stats_process.append(
-            (int(hs.get_clock().time()), resource.getrusage(resource.RUSAGE_SELF))
-        )
-
-    def start_phone_stats_home():
-        return run_as_background_process(
-            "phone_stats_home", phone_stats_home, hs, stats
-        )
-
-    def generate_user_daily_visit_stats():
-        return run_as_background_process(
-            "generate_user_daily_visits", hs.get_datastore().generate_user_daily_visits
-        )
-
-    # Rather than update on per session basis, batch up the requests.
-    # If you increase the loop period, the accuracy of user_daily_visits
-    # table will decrease
-    clock.looping_call(generate_user_daily_visit_stats, 5 * 60 * 1000)
-
-    # monthly active user limiting functionality
-    def reap_monthly_active_users():
-        return run_as_background_process(
-            "reap_monthly_active_users", hs.get_datastore().reap_monthly_active_users
-        )
-
-    clock.looping_call(reap_monthly_active_users, 1000 * 60 * 60)
-    reap_monthly_active_users()
-
-    async def generate_monthly_active_users():
-        current_mau_count = 0
-        current_mau_count_by_service = {}
-        reserved_users = ()
-        store = hs.get_datastore()
-        if hs.config.limit_usage_by_mau or hs.config.mau_stats_only:
-            current_mau_count = await store.get_monthly_active_count()
-            current_mau_count_by_service = (
-                await store.get_monthly_active_count_by_service()
-            )
-            reserved_users = await store.get_registered_reserved_users()
-        current_mau_gauge.set(float(current_mau_count))
-
-        for app_service, count in current_mau_count_by_service.items():
-            current_mau_by_service_gauge.labels(app_service).set(float(count))
-
-        registered_reserved_users_mau_gauge.set(float(len(reserved_users)))
-        max_mau_gauge.set(float(hs.config.max_mau_value))
-
-    def start_generate_monthly_active_users():
-        return run_as_background_process(
-            "generate_monthly_active_users", generate_monthly_active_users
-        )
-
-    start_generate_monthly_active_users()
-    if hs.config.limit_usage_by_mau or hs.config.mau_stats_only:
-        clock.looping_call(start_generate_monthly_active_users, 5 * 60 * 1000)
-    # End of monthly active user settings
-
-    if hs.config.report_stats:
-        logger.info("Scheduling stats reporting for 3 hour intervals")
-        clock.looping_call(start_phone_stats_home, 3 * 60 * 60 * 1000)
-
-        # We need to defer this init for the cases that we daemonize
-        # otherwise the process ID we get is that of the non-daemon process
-        clock.call_later(0, performance_stats_init)
-
-        # We wait 5 minutes to send the first set of stats as the server can
-        # be quite busy the first few minutes
-        clock.call_later(5 * 60, start_phone_stats_home)
-
     _base.start_reactor(
         "synapse-homeserver",
         soft_file_limit=hs.config.soft_file_limit,
diff --git a/synapse/app/phone_stats_home.py b/synapse/app/phone_stats_home.py
new file mode 100644
index 0000000000..c38cf8231f
--- /dev/null
+++ b/synapse/app/phone_stats_home.py
@@ -0,0 +1,190 @@
+#  Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+import logging
+import math
+import resource
+import sys
+
+from prometheus_client import Gauge
+
+from synapse.metrics.background_process_metrics import wrap_as_background_process
+
+logger = logging.getLogger("synapse.app.homeserver")
+
+# Contains the list of processes we will be monitoring
+# currently either 0 or 1
+_stats_process = []
+
+# Gauges to expose monthly active user control metrics
+current_mau_gauge = Gauge("synapse_admin_mau:current", "Current MAU")
+current_mau_by_service_gauge = Gauge(
+    "synapse_admin_mau_current_mau_by_service",
+    "Current MAU by service",
+    ["app_service"],
+)
+max_mau_gauge = Gauge("synapse_admin_mau:max", "MAU Limit")
+registered_reserved_users_mau_gauge = Gauge(
+    "synapse_admin_mau:registered_reserved_users",
+    "Registered users with reserved threepids",
+)
+
+
+@wrap_as_background_process("phone_stats_home")
+async def phone_stats_home(hs, stats, stats_process=_stats_process):
+    logger.info("Gathering stats for reporting")
+    now = int(hs.get_clock().time())
+    uptime = int(now - hs.start_time)
+    if uptime < 0:
+        uptime = 0
+
+    #
+    # Performance statistics. Keep this early in the function to maintain reliability of `test_performance_100` test.
+    #
+    old = stats_process[0]
+    new = (now, resource.getrusage(resource.RUSAGE_SELF))
+    stats_process[0] = new
+
+    # Get RSS in bytes
+    stats["memory_rss"] = new[1].ru_maxrss
+
+    # Get CPU time in % of a single core, not % of all cores
+    used_cpu_time = (new[1].ru_utime + new[1].ru_stime) - (
+        old[1].ru_utime + old[1].ru_stime
+    )
+    if used_cpu_time == 0 or new[0] == old[0]:
+        stats["cpu_average"] = 0
+    else:
+        stats["cpu_average"] = math.floor(used_cpu_time / (new[0] - old[0]) * 100)
+
+    #
+    # General statistics
+    #
+
+    stats["homeserver"] = hs.config.server_name
+    stats["server_context"] = hs.config.server_context
+    stats["timestamp"] = now
+    stats["uptime_seconds"] = uptime
+    version = sys.version_info
+    stats["python_version"] = "{}.{}.{}".format(
+        version.major, version.minor, version.micro
+    )
+    stats["total_users"] = await hs.get_datastore().count_all_users()
+
+    total_nonbridged_users = await hs.get_datastore().count_nonbridged_users()
+    stats["total_nonbridged_users"] = total_nonbridged_users
+
+    daily_user_type_results = await hs.get_datastore().count_daily_user_type()
+    for name, count in daily_user_type_results.items():
+        stats["daily_user_type_" + name] = count
+
+    room_count = await hs.get_datastore().get_room_count()
+    stats["total_room_count"] = room_count
+
+    stats["daily_active_users"] = await hs.get_datastore().count_daily_users()
+    stats["monthly_active_users"] = await hs.get_datastore().count_monthly_users()
+    stats["daily_active_rooms"] = await hs.get_datastore().count_daily_active_rooms()
+    stats["daily_messages"] = await hs.get_datastore().count_daily_messages()
+
+    r30_results = await hs.get_datastore().count_r30_users()
+    for name, count in r30_results.items():
+        stats["r30_users_" + name] = count
+
+    daily_sent_messages = await hs.get_datastore().count_daily_sent_messages()
+    stats["daily_sent_messages"] = daily_sent_messages
+    stats["cache_factor"] = hs.config.caches.global_factor
+    stats["event_cache_size"] = hs.config.caches.event_cache_size
+
+    #
+    # Database version
+    #
+
+    # This only reports info about the *main* database.
+    stats["database_engine"] = hs.get_datastore().db_pool.engine.module.__name__
+    stats["database_server_version"] = hs.get_datastore().db_pool.engine.server_version
+
+    #
+    # Logging configuration
+    #
+    synapse_logger = logging.getLogger("synapse")
+    log_level = synapse_logger.getEffectiveLevel()
+    stats["log_level"] = logging.getLevelName(log_level)
+
+    logger.info("Reporting stats to %s: %s" % (hs.config.report_stats_endpoint, stats))
+    try:
+        await hs.get_proxied_http_client().put_json(
+            hs.config.report_stats_endpoint, stats
+        )
+    except Exception as e:
+        logger.warning("Error reporting stats: %s", e)
+
+
+def start_phone_stats_home(hs):
+    """
+    Start the background tasks which report phone home stats.
+    """
+    clock = hs.get_clock()
+
+    stats = {}
+
+    def performance_stats_init():
+        _stats_process.clear()
+        _stats_process.append(
+            (int(hs.get_clock().time()), resource.getrusage(resource.RUSAGE_SELF))
+        )
+
+    # Rather than update on per session basis, batch up the requests.
+    # If you increase the loop period, the accuracy of user_daily_visits
+    # table will decrease
+    clock.looping_call(hs.get_datastore().generate_user_daily_visits, 5 * 60 * 1000)
+
+    # monthly active user limiting functionality
+    clock.looping_call(hs.get_datastore().reap_monthly_active_users, 1000 * 60 * 60)
+    hs.get_datastore().reap_monthly_active_users()
+
+    @wrap_as_background_process("generate_monthly_active_users")
+    async def generate_monthly_active_users():
+        current_mau_count = 0
+        current_mau_count_by_service = {}
+        reserved_users = ()
+        store = hs.get_datastore()
+        if hs.config.limit_usage_by_mau or hs.config.mau_stats_only:
+            current_mau_count = await store.get_monthly_active_count()
+            current_mau_count_by_service = (
+                await store.get_monthly_active_count_by_service()
+            )
+            reserved_users = await store.get_registered_reserved_users()
+        current_mau_gauge.set(float(current_mau_count))
+
+        for app_service, count in current_mau_count_by_service.items():
+            current_mau_by_service_gauge.labels(app_service).set(float(count))
+
+        registered_reserved_users_mau_gauge.set(float(len(reserved_users)))
+        max_mau_gauge.set(float(hs.config.max_mau_value))
+
+    if hs.config.limit_usage_by_mau or hs.config.mau_stats_only:
+        generate_monthly_active_users()
+        clock.looping_call(generate_monthly_active_users, 5 * 60 * 1000)
+    # End of monthly active user settings
+
+    if hs.config.report_stats:
+        logger.info("Scheduling stats reporting for 3 hour intervals")
+        clock.looping_call(phone_stats_home, 3 * 60 * 60 * 1000, hs, stats)
+
+        # We need to defer this init for the cases that we daemonize
+        # otherwise the process ID we get is that of the non-daemon process
+        clock.call_later(0, performance_stats_init)
+
+        # We wait 5 minutes to send the first set of stats as the server can
+        # be quite busy the first few minutes
+        clock.call_later(5 * 60, phone_stats_home, hs, stats)
diff --git a/synapse/appservice/__init__.py b/synapse/appservice/__init__.py
index 13ec1f71a6..3944780a42 100644
--- a/synapse/appservice/__init__.py
+++ b/synapse/appservice/__init__.py
@@ -14,14 +14,15 @@
 # limitations under the License.
 import logging
 import re
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Iterable, List, Match, Optional
 
 from synapse.api.constants import EventTypes
-from synapse.appservice.api import ApplicationServiceApi
-from synapse.types import GroupID, get_domain_from_id
-from synapse.util.caches.descriptors import cached
+from synapse.events import EventBase
+from synapse.types import GroupID, JsonDict, UserID, get_domain_from_id
+from synapse.util.caches.descriptors import _CacheContext, cached
 
 if TYPE_CHECKING:
+    from synapse.appservice.api import ApplicationServiceApi
     from synapse.storage.databases.main import DataStore
 
 logger = logging.getLogger(__name__)
@@ -32,38 +33,6 @@ class ApplicationServiceState:
     UP = "up"
 
 
-class AppServiceTransaction:
-    """Represents an application service transaction."""
-
-    def __init__(self, service, id, events):
-        self.service = service
-        self.id = id
-        self.events = events
-
-    async def send(self, as_api: ApplicationServiceApi) -> bool:
-        """Sends this transaction using the provided AS API interface.
-
-        Args:
-            as_api: The API to use to send.
-        Returns:
-            True if the transaction was sent.
-        """
-        return await as_api.push_bulk(
-            service=self.service, events=self.events, txn_id=self.id
-        )
-
-    async def complete(self, store: "DataStore") -> None:
-        """Completes this transaction as successful.
-
-        Marks this transaction ID on the application service and removes the
-        transaction contents from the database.
-
-        Args:
-            store: The database store to operate on.
-        """
-        await store.complete_appservice_txn(service=self.service, txn_id=self.id)
-
-
 class ApplicationService:
     """Defines an application service. This definition is mostly what is
     provided to the /register AS API.
@@ -83,14 +52,15 @@ class ApplicationService:
         self,
         token,
         hostname,
+        id,
+        sender,
         url=None,
         namespaces=None,
         hs_token=None,
-        sender=None,
-        id=None,
         protocols=None,
         rate_limited=True,
         ip_range_whitelist=None,
+        supports_ephemeral=False,
     ):
         self.token = token
         self.url = (
@@ -102,6 +72,7 @@ class ApplicationService:
         self.namespaces = self._check_namespaces(namespaces)
         self.id = id
         self.ip_range_whitelist = ip_range_whitelist
+        self.supports_ephemeral = supports_ephemeral
 
         if "|" in self.id:
             raise Exception("application service ID cannot contain '|' character")
@@ -161,19 +132,21 @@ class ApplicationService:
                     raise ValueError("Expected string for 'regex' in ns '%s'" % ns)
         return namespaces
 
-    def _matches_regex(self, test_string, namespace_key):
+    def _matches_regex(self, test_string: str, namespace_key: str) -> Optional[Match]:
         for regex_obj in self.namespaces[namespace_key]:
             if regex_obj["regex"].match(test_string):
                 return regex_obj
         return None
 
-    def _is_exclusive(self, ns_key, test_string):
+    def _is_exclusive(self, ns_key: str, test_string: str) -> bool:
         regex_obj = self._matches_regex(test_string, ns_key)
         if regex_obj:
             return regex_obj["exclusive"]
         return False
 
-    async def _matches_user(self, event, store):
+    async def _matches_user(
+        self, event: Optional[EventBase], store: Optional["DataStore"] = None
+    ) -> bool:
         if not event:
             return False
 
@@ -188,11 +161,22 @@ class ApplicationService:
         if not store:
             return False
 
-        does_match = await self._matches_user_in_member_list(event.room_id, store)
+        does_match = await self.matches_user_in_member_list(event.room_id, store)
         return does_match
 
     @cached(num_args=1, cache_context=True)
-    async def _matches_user_in_member_list(self, room_id, store, cache_context):
+    async def matches_user_in_member_list(
+        self, room_id: str, store: "DataStore", cache_context: _CacheContext,
+    ) -> bool:
+        """Check if this service is interested a room based upon it's membership
+
+        Args:
+            room_id: The room to check.
+            store: The datastore to query.
+
+        Returns:
+            True if this service would like to know about this room.
+        """
         member_list = await store.get_users_in_room(
             room_id, on_invalidate=cache_context.invalidate
         )
@@ -203,12 +187,14 @@ class ApplicationService:
                 return True
         return False
 
-    def _matches_room_id(self, event):
+    def _matches_room_id(self, event: EventBase) -> bool:
         if hasattr(event, "room_id"):
             return self.is_interested_in_room(event.room_id)
         return False
 
-    async def _matches_aliases(self, event, store):
+    async def _matches_aliases(
+        self, event: EventBase, store: Optional["DataStore"] = None
+    ) -> bool:
         if not store or not event:
             return False
 
@@ -218,12 +204,15 @@ class ApplicationService:
                 return True
         return False
 
-    async def is_interested(self, event, store=None) -> bool:
+    async def is_interested(
+        self, event: EventBase, store: Optional["DataStore"] = None
+    ) -> bool:
         """Check if this service is interested in this event.
 
         Args:
-            event(Event): The event to check.
-            store(DataStore)
+            event: The event to check.
+            store: The datastore to query.
+
         Returns:
             True if this service would like to know about this event.
         """
@@ -231,39 +220,66 @@ class ApplicationService:
         if self._matches_room_id(event):
             return True
 
-        if await self._matches_aliases(event, store):
+        # This will check the namespaces first before
+        # checking the store, so should be run before _matches_aliases
+        if await self._matches_user(event, store):
             return True
 
-        if await self._matches_user(event, store):
+        # This will check the store, so should be run last
+        if await self._matches_aliases(event, store):
             return True
 
         return False
 
-    def is_interested_in_user(self, user_id):
+    @cached(num_args=1)
+    async def is_interested_in_presence(
+        self, user_id: UserID, store: "DataStore"
+    ) -> bool:
+        """Check if this service is interested a user's presence
+
+        Args:
+            user_id: The user to check.
+            store: The datastore to query.
+
+        Returns:
+            True if this service would like to know about presence for this user.
+        """
+        # Find all the rooms the sender is in
+        if self.is_interested_in_user(user_id.to_string()):
+            return True
+        room_ids = await store.get_rooms_for_user(user_id.to_string())
+
+        # Then find out if the appservice is interested in any of those rooms
+        for room_id in room_ids:
+            if await self.matches_user_in_member_list(room_id, store):
+                return True
+        return False
+
+    def is_interested_in_user(self, user_id: str) -> bool:
         return (
-            self._matches_regex(user_id, ApplicationService.NS_USERS)
+            bool(self._matches_regex(user_id, ApplicationService.NS_USERS))
             or user_id == self.sender
         )
 
-    def is_interested_in_alias(self, alias):
+    def is_interested_in_alias(self, alias: str) -> bool:
         return bool(self._matches_regex(alias, ApplicationService.NS_ALIASES))
 
-    def is_interested_in_room(self, room_id):
+    def is_interested_in_room(self, room_id: str) -> bool:
         return bool(self._matches_regex(room_id, ApplicationService.NS_ROOMS))
 
-    def is_exclusive_user(self, user_id):
+    def is_exclusive_user(self, user_id: str) -> bool:
         return (
             self._is_exclusive(ApplicationService.NS_USERS, user_id)
             or user_id == self.sender
         )
 
-    def is_interested_in_protocol(self, protocol):
+    def is_interested_in_protocol(self, protocol: str) -> bool:
         return protocol in self.protocols
 
-    def is_exclusive_alias(self, alias):
+    def is_exclusive_alias(self, alias: str) -> bool:
         return self._is_exclusive(ApplicationService.NS_ALIASES, alias)
 
-    def is_exclusive_room(self, room_id):
+    def is_exclusive_room(self, room_id: str) -> bool:
         return self._is_exclusive(ApplicationService.NS_ROOMS, room_id)
 
     def get_exclusive_user_regexes(self):
@@ -276,14 +292,14 @@ class ApplicationService:
             if regex_obj["exclusive"]
         ]
 
-    def get_groups_for_user(self, user_id):
+    def get_groups_for_user(self, user_id: str) -> Iterable[str]:
         """Get the groups that this user is associated with by this AS
 
         Args:
-            user_id (str): The ID of the user.
+            user_id: The ID of the user.
 
         Returns:
-            iterable[str]: an iterable that yields group_id strings.
+            An iterable that yields group_id strings.
         """
         return (
             regex_obj["group_id"]
@@ -291,7 +307,7 @@ class ApplicationService:
             if "group_id" in regex_obj and regex_obj["regex"].match(user_id)
         )
 
-    def is_rate_limited(self):
+    def is_rate_limited(self) -> bool:
         return self.rate_limited
 
     def __str__(self):
@@ -300,3 +316,45 @@ class ApplicationService:
         dict_copy["token"] = "<redacted>"
         dict_copy["hs_token"] = "<redacted>"
         return "ApplicationService: %s" % (dict_copy,)
+
+
+class AppServiceTransaction:
+    """Represents an application service transaction."""
+
+    def __init__(
+        self,
+        service: ApplicationService,
+        id: int,
+        events: List[EventBase],
+        ephemeral: List[JsonDict],
+    ):
+        self.service = service
+        self.id = id
+        self.events = events
+        self.ephemeral = ephemeral
+
+    async def send(self, as_api: "ApplicationServiceApi") -> bool:
+        """Sends this transaction using the provided AS API interface.
+
+        Args:
+            as_api: The API to use to send.
+        Returns:
+            True if the transaction was sent.
+        """
+        return await as_api.push_bulk(
+            service=self.service,
+            events=self.events,
+            ephemeral=self.ephemeral,
+            txn_id=self.id,
+        )
+
+    async def complete(self, store: "DataStore") -> None:
+        """Completes this transaction as successful.
+
+        Marks this transaction ID on the application service and removes the
+        transaction contents from the database.
+
+        Args:
+            store: The database store to operate on.
+        """
+        await store.complete_appservice_txn(service=self.service, txn_id=self.id)
diff --git a/synapse/appservice/api.py b/synapse/appservice/api.py
index c526c28b93..e366a982b8 100644
--- a/synapse/appservice/api.py
+++ b/synapse/appservice/api.py
@@ -14,12 +14,13 @@
 # limitations under the License.
 import logging
 import urllib
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING, List, Optional, Tuple
 
 from prometheus_client import Counter
 
 from synapse.api.constants import EventTypes, ThirdPartyEntityKind
 from synapse.api.errors import CodeMessageException
+from synapse.events import EventBase
 from synapse.events.utils import serialize_event
 from synapse.http.client import SimpleHttpClient
 from synapse.types import JsonDict, ThirdPartyInstanceID
@@ -93,7 +94,7 @@ class ApplicationServiceApi(SimpleHttpClient):
 
         self.protocol_meta_cache = ResponseCache(
             hs, "as_protocol_meta", timeout_ms=HOUR_IN_MS
-        )
+        )  # type: ResponseCache[Tuple[str, str]]
 
     async def query_user(self, service, user_id):
         if service.url is None:
@@ -201,7 +202,13 @@ class ApplicationServiceApi(SimpleHttpClient):
         key = (service.id, protocol)
         return await self.protocol_meta_cache.wrap(key, _get)
 
-    async def push_bulk(self, service, events, txn_id=None):
+    async def push_bulk(
+        self,
+        service: "ApplicationService",
+        events: List[EventBase],
+        ephemeral: List[JsonDict],
+        txn_id: Optional[int] = None,
+    ):
         if service.url is None:
             return True
 
@@ -211,15 +218,19 @@ class ApplicationServiceApi(SimpleHttpClient):
             logger.warning(
                 "push_bulk: Missing txn ID sending events to %s", service.url
             )
-            txn_id = str(0)
-        txn_id = str(txn_id)
+            txn_id = 0
+
+        uri = service.url + ("/transactions/%s" % urllib.parse.quote(str(txn_id)))
+
+        # Never send ephemeral events to appservices that do not support it
+        if service.supports_ephemeral:
+            body = {"events": events, "de.sorunome.msc2409.ephemeral": ephemeral}
+        else:
+            body = {"events": events}
 
-        uri = service.url + ("/transactions/%s" % urllib.parse.quote(txn_id))
         try:
             await self.put_json(
-                uri=uri,
-                json_body={"events": events},
-                args={"access_token": service.hs_token},
+                uri=uri, json_body=body, args={"access_token": service.hs_token},
             )
             sent_transactions_counter.labels(service.id).inc()
             sent_events_counter.labels(service.id).inc(len(events))
diff --git a/synapse/appservice/scheduler.py b/synapse/appservice/scheduler.py
index 8eb8c6f51c..58291afc22 100644
--- a/synapse/appservice/scheduler.py
+++ b/synapse/appservice/scheduler.py
@@ -49,14 +49,24 @@ This is all tied together by the AppServiceScheduler which DIs the required
 components.
 """
 import logging
+from typing import List
 
-from synapse.appservice import ApplicationServiceState
+from synapse.appservice import ApplicationService, ApplicationServiceState
+from synapse.events import EventBase
 from synapse.logging.context import run_in_background
 from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.types import JsonDict
 
 logger = logging.getLogger(__name__)
 
 
+# Maximum number of events to provide in an AS transaction.
+MAX_PERSISTENT_EVENTS_PER_TRANSACTION = 100
+
+# Maximum number of ephemeral events to provide in an AS transaction.
+MAX_EPHEMERAL_EVENTS_PER_TRANSACTION = 100
+
+
 class ApplicationServiceScheduler:
     """ Public facing API for this module. Does the required DI to tie the
     components together. This also serves as the "event_pool", which in this
@@ -82,8 +92,13 @@ class ApplicationServiceScheduler:
         for service in services:
             self.txn_ctrl.start_recoverer(service)
 
-    def submit_event_for_as(self, service, event):
-        self.queuer.enqueue(service, event)
+    def submit_event_for_as(self, service: ApplicationService, event: EventBase):
+        self.queuer.enqueue_event(service, event)
+
+    def submit_ephemeral_events_for_as(
+        self, service: ApplicationService, events: List[JsonDict]
+    ):
+        self.queuer.enqueue_ephemeral(service, events)
 
 
 class _ServiceQueuer:
@@ -96,17 +111,15 @@ class _ServiceQueuer:
 
     def __init__(self, txn_ctrl, clock):
         self.queued_events = {}  # dict of {service_id: [events]}
+        self.queued_ephemeral = {}  # dict of {service_id: [events]}
 
         # the appservices which currently have a transaction in flight
         self.requests_in_flight = set()
         self.txn_ctrl = txn_ctrl
         self.clock = clock
 
-    def enqueue(self, service, event):
-        self.queued_events.setdefault(service.id, []).append(event)
-
+    def _start_background_request(self, service):
         # start a sender for this appservice if we don't already have one
-
         if service.id in self.requests_in_flight:
             return
 
@@ -114,7 +127,15 @@ class _ServiceQueuer:
             "as-sender-%s" % (service.id,), self._send_request, service
         )
 
-    async def _send_request(self, service):
+    def enqueue_event(self, service: ApplicationService, event: EventBase):
+        self.queued_events.setdefault(service.id, []).append(event)
+        self._start_background_request(service)
+
+    def enqueue_ephemeral(self, service: ApplicationService, events: List[JsonDict]):
+        self.queued_ephemeral.setdefault(service.id, []).extend(events)
+        self._start_background_request(service)
+
+    async def _send_request(self, service: ApplicationService):
         # sanity-check: we shouldn't get here if this service already has a sender
         # running.
         assert service.id not in self.requests_in_flight
@@ -122,11 +143,19 @@ class _ServiceQueuer:
         self.requests_in_flight.add(service.id)
         try:
             while True:
-                events = self.queued_events.pop(service.id, [])
-                if not events:
+                all_events = self.queued_events.get(service.id, [])
+                events = all_events[:MAX_PERSISTENT_EVENTS_PER_TRANSACTION]
+                del all_events[:MAX_PERSISTENT_EVENTS_PER_TRANSACTION]
+
+                all_events_ephemeral = self.queued_ephemeral.get(service.id, [])
+                ephemeral = all_events_ephemeral[:MAX_EPHEMERAL_EVENTS_PER_TRANSACTION]
+                del all_events_ephemeral[:MAX_EPHEMERAL_EVENTS_PER_TRANSACTION]
+
+                if not events and not ephemeral:
                     return
+
                 try:
-                    await self.txn_ctrl.send(service, events)
+                    await self.txn_ctrl.send(service, events, ephemeral)
                 except Exception:
                     logger.exception("AS request failed")
         finally:
@@ -158,9 +187,16 @@ class _TransactionController:
         # for UTs
         self.RECOVERER_CLASS = _Recoverer
 
-    async def send(self, service, events):
+    async def send(
+        self,
+        service: ApplicationService,
+        events: List[EventBase],
+        ephemeral: List[JsonDict] = [],
+    ):
         try:
-            txn = await self.store.create_appservice_txn(service=service, events=events)
+            txn = await self.store.create_appservice_txn(
+                service=service, events=events, ephemeral=ephemeral
+            )
             service_is_up = await self._is_service_up(service)
             if service_is_up:
                 sent = await txn.send(self.as_api)
@@ -204,7 +240,7 @@ class _TransactionController:
         recoverer.recover()
         logger.info("Now %i active recoverers", len(self.recoverers))
 
-    async def _is_service_up(self, service):
+    async def _is_service_up(self, service: ApplicationService) -> bool:
         state = await self.store.get_appservice_state(service)
         return state == ApplicationServiceState.UP or state is None
 
diff --git a/synapse/config/appservice.py b/synapse/config/appservice.py
index 8ed3e24258..746fc3cc02 100644
--- a/synapse/config/appservice.py
+++ b/synapse/config/appservice.py
@@ -160,6 +160,8 @@ def _load_appservice(hostname, as_info, config_filename):
     if as_info.get("ip_range_whitelist"):
         ip_range_whitelist = IPSet(as_info.get("ip_range_whitelist"))
 
+    supports_ephemeral = as_info.get("de.sorunome.msc2409.push_ephemeral", False)
+
     return ApplicationService(
         token=as_info["as_token"],
         hostname=hostname,
@@ -168,6 +170,7 @@ def _load_appservice(hostname, as_info, config_filename):
         hs_token=as_info["hs_token"],
         sender=user_id,
         id=as_info["id"],
+        supports_ephemeral=supports_ephemeral,
         protocols=protocols,
         rate_limited=rate_limited,
         ip_range_whitelist=ip_range_whitelist,
diff --git a/synapse/config/cas.py b/synapse/config/cas.py
index 4526c1a67b..2f97e6d258 100644
--- a/synapse/config/cas.py
+++ b/synapse/config/cas.py
@@ -26,14 +26,14 @@ class CasConfig(Config):
 
     def read_config(self, config, **kwargs):
         cas_config = config.get("cas_config", None)
-        if cas_config:
-            self.cas_enabled = cas_config.get("enabled", True)
+        self.cas_enabled = cas_config and cas_config.get("enabled", True)
+
+        if self.cas_enabled:
             self.cas_server_url = cas_config["server_url"]
             self.cas_service_url = cas_config["service_url"]
             self.cas_displayname_attribute = cas_config.get("displayname_attribute")
-            self.cas_required_attributes = cas_config.get("required_attributes", {})
+            self.cas_required_attributes = cas_config.get("required_attributes") or {}
         else:
-            self.cas_enabled = False
             self.cas_server_url = None
             self.cas_service_url = None
             self.cas_displayname_attribute = None
@@ -41,13 +41,35 @@ class CasConfig(Config):
 
     def generate_config_section(self, config_dir_path, server_name, **kwargs):
         return """
-        # Enable CAS for registration and login.
+        # Enable Central Authentication Service (CAS) for registration and login.
         #
-        #cas_config:
-        #   enabled: true
-        #   server_url: "https://cas-server.com"
-        #   service_url: "https://homeserver.domain.com:8448"
-        #   #displayname_attribute: name
-        #   #required_attributes:
-        #   #    name: value
+        cas_config:
+          # Uncomment the following to enable authorization against a CAS server.
+          # Defaults to false.
+          #
+          #enabled: true
+
+          # The URL of the CAS authorization endpoint.
+          #
+          #server_url: "https://cas-server.com"
+
+          # The public URL of the homeserver.
+          #
+          #service_url: "https://homeserver.domain.com:8448"
+
+          # The attribute of the CAS response to use as the display name.
+          #
+          # If unset, no displayname will be set.
+          #
+          #displayname_attribute: name
+
+          # It is possible to configure Synapse to only allow logins if CAS attributes
+          # match particular values. All of the keys in the mapping below must exist
+          # and the values must match the given value. Alternately if the given value
+          # is None then any value is allowed (the attribute just must exist).
+          # All of the listed attributes must match for the login to be permitted.
+          #
+          #required_attributes:
+          #  userGroup: "staff"
+          #  department: None
         """
diff --git a/synapse/config/jwt_config.py b/synapse/config/jwt_config.py
index 3252ad9e7f..f30330abb6 100644
--- a/synapse/config/jwt_config.py
+++ b/synapse/config/jwt_config.py
@@ -63,7 +63,7 @@ class JWTConfig(Config):
         # and issued at ("iat") claims are validated if present.
         #
         # Note that this is a non-standard login type and client support is
-        # expected to be non-existant.
+        # expected to be non-existent.
         #
         # See https://github.com/matrix-org/synapse/blob/master/docs/jwt.md.
         #
diff --git a/synapse/config/logger.py b/synapse/config/logger.py
index 13d6f6a3ea..d4e887a3e0 100644
--- a/synapse/config/logger.py
+++ b/synapse/config/logger.py
@@ -23,7 +23,6 @@ from string import Template
 import yaml
 
 from twisted.logger import (
-    ILogObserver,
     LogBeginner,
     STDLibLogObserver,
     eventAsText,
@@ -32,11 +31,9 @@ from twisted.logger import (
 
 import synapse
 from synapse.app import _base as appbase
-from synapse.logging._structured import (
-    reload_structured_logging,
-    setup_structured_logging,
-)
+from synapse.logging._structured import setup_structured_logging
 from synapse.logging.context import LoggingContextFilter
+from synapse.logging.filter import MetadataFilter
 from synapse.util.versionstring import get_version_string
 
 from ._base import Config, ConfigError
@@ -48,7 +45,11 @@ DEFAULT_LOG_CONFIG = Template(
 # This is a YAML file containing a standard Python logging configuration
 # dictionary. See [1] for details on the valid settings.
 #
+# Synapse also supports structured logging for machine readable logs which can
+# be ingested by ELK stacks. See [2] for details.
+#
 # [1]: https://docs.python.org/3.7/library/logging.config.html#configuration-dictionary-schema
+# [2]: https://github.com/matrix-org/synapse/blob/master/docs/structured_logging.md
 
 version: 1
 
@@ -105,7 +106,7 @@ root:
     # then write them to a file.
     #
     # Replace "buffer" with "console" to log to stderr instead. (Note that you'll
-    # also need to update the configuation for the `twisted` logger above, in
+    # also need to update the configuration for the `twisted` logger above, in
     # this case.)
     #
     handlers: [buffer]
@@ -176,11 +177,11 @@ class LoggingConfig(Config):
                 log_config_file.write(DEFAULT_LOG_CONFIG.substitute(log_file=log_file))
 
 
-def _setup_stdlib_logging(config, log_config, logBeginner: LogBeginner):
+def _setup_stdlib_logging(config, log_config_path, logBeginner: LogBeginner) -> None:
     """
-    Set up Python stdlib logging.
+    Set up Python standard library logging.
     """
-    if log_config is None:
+    if log_config_path is None:
         log_format = (
             "%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s"
             " - %(message)s"
@@ -196,7 +197,8 @@ def _setup_stdlib_logging(config, log_config, logBeginner: LogBeginner):
         handler.setFormatter(formatter)
         logger.addHandler(handler)
     else:
-        logging.config.dictConfig(log_config)
+        # Load the logging configuration.
+        _load_logging_config(log_config_path)
 
     # We add a log record factory that runs all messages through the
     # LoggingContextFilter so that we get the context *at the time we log*
@@ -204,12 +206,14 @@ def _setup_stdlib_logging(config, log_config, logBeginner: LogBeginner):
     # filter options, but care must when using e.g. MemoryHandler to buffer
     # writes.
 
-    log_filter = LoggingContextFilter(request="")
+    log_context_filter = LoggingContextFilter(request="")
+    log_metadata_filter = MetadataFilter({"server_name": config.server_name})
     old_factory = logging.getLogRecordFactory()
 
     def factory(*args, **kwargs):
         record = old_factory(*args, **kwargs)
-        log_filter.filter(record)
+        log_context_filter.filter(record)
+        log_metadata_filter.filter(record)
         return record
 
     logging.setLogRecordFactory(factory)
@@ -255,21 +259,40 @@ def _setup_stdlib_logging(config, log_config, logBeginner: LogBeginner):
     if not config.no_redirect_stdio:
         print("Redirected stdout/stderr to logs")
 
-    return observer
 
-
-def _reload_stdlib_logging(*args, log_config=None):
-    logger = logging.getLogger("")
+def _load_logging_config(log_config_path: str) -> None:
+    """
+    Configure logging from a log config path.
+    """
+    with open(log_config_path, "rb") as f:
+        log_config = yaml.safe_load(f.read())
 
     if not log_config:
-        logger.warning("Reloaded a blank config?")
+        logging.warning("Loaded a blank logging config?")
+
+    # If the old structured logging configuration is being used, convert it to
+    # the new style configuration.
+    if "structured" in log_config and log_config.get("structured"):
+        log_config = setup_structured_logging(log_config)
 
     logging.config.dictConfig(log_config)
 
 
+def _reload_logging_config(log_config_path):
+    """
+    Reload the log configuration from the file and apply it.
+    """
+    # If no log config path was given, it cannot be reloaded.
+    if log_config_path is None:
+        return
+
+    _load_logging_config(log_config_path)
+    logging.info("Reloaded log config from %s due to SIGHUP", log_config_path)
+
+
 def setup_logging(
     hs, config, use_worker_options=False, logBeginner: LogBeginner = globalLogBeginner
-) -> ILogObserver:
+) -> None:
     """
     Set up the logging subsystem.
 
@@ -282,41 +305,18 @@ def setup_logging(
 
         logBeginner: The Twisted logBeginner to use.
 
-    Returns:
-        The "root" Twisted Logger observer, suitable for sending logs to from a
-        Logger instance.
     """
-    log_config = config.worker_log_config if use_worker_options else config.log_config
+    log_config_path = (
+        config.worker_log_config if use_worker_options else config.log_config
+    )
 
-    def read_config(*args, callback=None):
-        if log_config is None:
-            return None
+    # Perform one-time logging configuration.
+    _setup_stdlib_logging(config, log_config_path, logBeginner=logBeginner)
+    # Add a SIGHUP handler to reload the logging configuration, if one is available.
+    appbase.register_sighup(_reload_logging_config, log_config_path)
 
-        with open(log_config, "rb") as f:
-            log_config_body = yaml.safe_load(f.read())
-
-        if callback:
-            callback(log_config=log_config_body)
-            logging.info("Reloaded log config from %s due to SIGHUP", log_config)
-
-        return log_config_body
-
-    log_config_body = read_config()
-
-    if log_config_body and log_config_body.get("structured") is True:
-        logger = setup_structured_logging(
-            hs, config, log_config_body, logBeginner=logBeginner
-        )
-        appbase.register_sighup(read_config, callback=reload_structured_logging)
-    else:
-        logger = _setup_stdlib_logging(config, log_config_body, logBeginner=logBeginner)
-        appbase.register_sighup(read_config, callback=_reload_stdlib_logging)
-
-    # make sure that the first thing we log is a thing we can grep backwards
-    # for
+    # Log immediately so we can grep backwards.
     logging.warning("***** STARTING SERVER *****")
     logging.warning("Server %s version %s", sys.argv[0], get_version_string(synapse))
     logging.info("Server hostname: %s", config.server_name)
     logging.info("Instance name: %s", hs.get_instance_name())
-
-    return logger
diff --git a/synapse/config/oidc_config.py b/synapse/config/oidc_config.py
index f924116819..69d188341c 100644
--- a/synapse/config/oidc_config.py
+++ b/synapse/config/oidc_config.py
@@ -56,6 +56,7 @@ class OIDCConfig(Config):
         self.oidc_userinfo_endpoint = oidc_config.get("userinfo_endpoint")
         self.oidc_jwks_uri = oidc_config.get("jwks_uri")
         self.oidc_skip_verification = oidc_config.get("skip_verification", False)
+        self.oidc_user_profile_method = oidc_config.get("user_profile_method", "auto")
         self.oidc_allow_existing_users = oidc_config.get("allow_existing_users", False)
 
         ump_config = oidc_config.get("user_mapping_provider", {})
@@ -86,11 +87,10 @@ class OIDCConfig(Config):
 
     def generate_config_section(self, config_dir_path, server_name, **kwargs):
         return """\
-        # OpenID Connect integration. The following settings can be used to make Synapse
-        # use an OpenID Connect Provider for authentication, instead of its internal
-        # password database.
+        # Enable OpenID Connect (OIDC) / OAuth 2.0 for registration and login.
         #
-        # See https://github.com/matrix-org/synapse/blob/master/docs/openid.md.
+        # See https://github.com/matrix-org/synapse/blob/master/docs/openid.md
+        # for some example configurations.
         #
         oidc_config:
           # Uncomment the following to enable authorization against an OpenID Connect
@@ -159,6 +159,14 @@ class OIDCConfig(Config):
           #
           #skip_verification: true
 
+          # Whether to fetch the user profile from the userinfo endpoint. Valid
+          # values are: "auto" or "userinfo_endpoint".
+          #
+          # Defaults to "auto", which fetches the userinfo endpoint if "openid" is included
+          # in `scopes`. Uncomment the following to always fetch the userinfo endpoint.
+          #
+          #user_profile_method: "userinfo_endpoint"
+
           # Uncomment to allow a user logging in via OIDC to match a pre-existing account instead
           # of failing. This could be used if switching from password logins to OIDC. Defaults to false.
           #
diff --git a/synapse/config/push.py b/synapse/config/push.py
index a1f3752c8a..3adbfb73e6 100644
--- a/synapse/config/push.py
+++ b/synapse/config/push.py
@@ -21,8 +21,11 @@ class PushConfig(Config):
     section = "push"
 
     def read_config(self, config, **kwargs):
-        push_config = config.get("push", {})
+        push_config = config.get("push") or {}
         self.push_include_content = push_config.get("include_content", True)
+        self.push_group_unread_count_by_room = push_config.get(
+            "group_unread_count_by_room", True
+        )
 
         pusher_instances = config.get("pusher_instances") or []
         self.pusher_shard_config = ShardedWorkerHandlingConfig(pusher_instances)
@@ -49,18 +52,33 @@ class PushConfig(Config):
 
     def generate_config_section(self, config_dir_path, server_name, **kwargs):
         return """
-        # Clients requesting push notifications can either have the body of
-        # the message sent in the notification poke along with other details
-        # like the sender, or just the event ID and room ID (`event_id_only`).
-        # If clients choose the former, this option controls whether the
-        # notification request includes the content of the event (other details
-        # like the sender are still included). For `event_id_only` push, it
-        # has no effect.
-        #
-        # For modern android devices the notification content will still appear
-        # because it is loaded by the app. iPhone, however will send a
-        # notification saying only that a message arrived and who it came from.
-        #
-        #push:
-        #  include_content: true
+        ## Push ##
+
+        push:
+          # Clients requesting push notifications can either have the body of
+          # the message sent in the notification poke along with other details
+          # like the sender, or just the event ID and room ID (`event_id_only`).
+          # If clients choose the former, this option controls whether the
+          # notification request includes the content of the event (other details
+          # like the sender are still included). For `event_id_only` push, it
+          # has no effect.
+          #
+          # For modern android devices the notification content will still appear
+          # because it is loaded by the app. iPhone, however will send a
+          # notification saying only that a message arrived and who it came from.
+          #
+          # The default value is "true" to include message details. Uncomment to only
+          # include the event ID and room ID in push notification payloads.
+          #
+          #include_content: false
+
+          # When a push notification is received, an unread count is also sent.
+          # This number can either be calculated as the number of unread messages
+          # for the user, or the number of *rooms* the user has unread messages in.
+          #
+          # The default value is "true", meaning push clients will see the number of
+          # rooms with unread messages in them. Uncomment to instead send the number
+          # of unread messages.
+          #
+          #group_unread_count_by_room: false
         """
diff --git a/synapse/config/registration.py b/synapse/config/registration.py
index dbe8ddc7ac..770b921aff 100644
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -103,7 +103,7 @@ class RegistrationConfig(Config):
             RoomCreationPreset.TRUSTED_PRIVATE_CHAT,
         }
 
-        # Pull the creater/inviter from the configuration, this gets used to
+        # Pull the creator/inviter from the configuration, this gets used to
         # send invites for invite-only rooms.
         mxid_localpart = config.get("auto_join_mxid_localpart")
         self.auto_join_user_id = None
@@ -322,8 +322,9 @@ class RegistrationConfig(Config):
         # email will be globally disabled.
         #
         # Additionally, if `msisdn` is not set, registration and password resets via msisdn
-        # will be disabled regardless. This is due to Synapse currently not supporting any
-        # method of sending SMS messages on its own.
+        # will be disabled regardless, and users will not be able to associate an msisdn
+        # identifier to their account. This is due to Synapse currently not supporting
+        # any method of sending SMS messages on its own.
         #
         # To enable using an identity server for operations regarding a particular third-party
         # identifier type, set the value to the URL of that identity server as shown in the
diff --git a/synapse/config/repository.py b/synapse/config/repository.py
index 54f565ad5b..bc02754a33 100644
--- a/synapse/config/repository.py
+++ b/synapse/config/repository.py
@@ -100,7 +100,7 @@ class ContentRepositoryConfig(Config):
             "media_instance_running_background_jobs",
         )
 
-        self.max_upload_size = self.parse_size(config.get("max_upload_size", "10M"))
+        self.max_upload_size = self.parse_size(config.get("max_upload_size", "50M"))
         self.max_image_pixels = self.parse_size(config.get("max_image_pixels", "32M"))
         self.max_spider_size = self.parse_size(config.get("max_spider_size", "10M"))
 
@@ -248,7 +248,7 @@ class ContentRepositoryConfig(Config):
 
         # The largest allowed upload size in bytes
         #
-        #max_upload_size: 10M
+        #max_upload_size: 50M
 
         # The largest allowed size for a user avatar. If not defined, no
         # restriction will be imposed.
diff --git a/synapse/config/room_directory.py b/synapse/config/room_directory.py
index 6de1f9d103..92e1b67528 100644
--- a/synapse/config/room_directory.py
+++ b/synapse/config/room_directory.py
@@ -99,7 +99,7 @@ class RoomDirectoryConfig(Config):
         #
         # Options for the rules include:
         #
-        #   user_id: Matches agaisnt the creator of the alias
+        #   user_id: Matches against the creator of the alias
         #   room_id: Matches against the room ID being published
         #   alias: Matches against any current local or canonical aliases
         #            associated with the room
diff --git a/synapse/config/saml2_config.py b/synapse/config/saml2_config.py
index 99aa8b3bf1..c1b8e98ae0 100644
--- a/synapse/config/saml2_config.py
+++ b/synapse/config/saml2_config.py
@@ -90,6 +90,8 @@ class SAML2Config(Config):
             "grandfathered_mxid_source_attribute", "uid"
         )
 
+        self.saml2_idp_entityid = saml2_config.get("idp_entityid", None)
+
         # user_mapping_provider may be None if the key is present but has no value
         ump_dict = saml2_config.get("user_mapping_provider") or {}
 
@@ -216,10 +218,8 @@ class SAML2Config(Config):
         return """\
         ## Single sign-on integration ##
 
-        # Enable SAML2 for registration and login. Uses pysaml2.
-        #
-        # At least one of `sp_config` or `config_path` must be set in this section to
-        # enable SAML login.
+        # The following settings can be used to make Synapse use a single sign-on
+        # provider for authentication, instead of its internal password database.
         #
         # You will probably also want to set the following options to `false` to
         # disable the regular login/registration flows:
@@ -228,6 +228,11 @@ class SAML2Config(Config):
         #
         # You will also want to investigate the settings under the "sso" configuration
         # section below.
+
+        # Enable SAML2 for registration and login. Uses pysaml2.
+        #
+        # At least one of `sp_config` or `config_path` must be set in this section to
+        # enable SAML login.
         #
         # Once SAML support is enabled, a metadata file will be exposed at
         # https://<server>:<port>/_matrix/saml2/metadata.xml, which you may be able to
@@ -243,40 +248,70 @@ class SAML2Config(Config):
           # so it is not normally necessary to specify them unless you need to
           # override them.
           #
-          #sp_config:
-          #  # point this to the IdP's metadata. You can use either a local file or
-          #  # (preferably) a URL.
-          #  metadata:
-          #    #local: ["saml2/idp.xml"]
-          #    remote:
-          #      - url: https://our_idp/metadata.xml
-          #
-          #  # By default, the user has to go to our login page first. If you'd like
-          #  # to allow IdP-initiated login, set 'allow_unsolicited: true' in a
-          #  # 'service.sp' section:
-          #  #
-          #  #service:
-          #  #  sp:
-          #  #    allow_unsolicited: true
-          #
-          #  # The examples below are just used to generate our metadata xml, and you
-          #  # may well not need them, depending on your setup. Alternatively you
-          #  # may need a whole lot more detail - see the pysaml2 docs!
-          #
-          #  description: ["My awesome SP", "en"]
-          #  name: ["Test SP", "en"]
-          #
-          #  organization:
-          #    name: Example com
-          #    display_name:
-          #      - ["Example co", "en"]
-          #    url: "http://example.com"
-          #
-          #  contact_person:
-          #    - given_name: Bob
-          #      sur_name: "the Sysadmin"
-          #      email_address": ["admin@example.com"]
-          #      contact_type": technical
+          sp_config:
+            # Point this to the IdP's metadata. You must provide either a local
+            # file via the `local` attribute or (preferably) a URL via the
+            # `remote` attribute.
+            #
+            #metadata:
+            #  local: ["saml2/idp.xml"]
+            #  remote:
+            #    - url: https://our_idp/metadata.xml
+
+            # Allowed clock difference in seconds between the homeserver and IdP.
+            #
+            # Uncomment the below to increase the accepted time difference from 0 to 3 seconds.
+            #
+            #accepted_time_diff: 3
+
+            # By default, the user has to go to our login page first. If you'd like
+            # to allow IdP-initiated login, set 'allow_unsolicited: true' in a
+            # 'service.sp' section:
+            #
+            #service:
+            #  sp:
+            #    allow_unsolicited: true
+
+            # The examples below are just used to generate our metadata xml, and you
+            # may well not need them, depending on your setup. Alternatively you
+            # may need a whole lot more detail - see the pysaml2 docs!
+
+            #description: ["My awesome SP", "en"]
+            #name: ["Test SP", "en"]
+
+            #ui_info:
+            #  display_name:
+            #    - lang: en
+            #      text: "Display Name is the descriptive name of your service."
+            #  description:
+            #    - lang: en
+            #      text: "Description should be a short paragraph explaining the purpose of the service."
+            #  information_url:
+            #    - lang: en
+            #      text: "https://example.com/terms-of-service"
+            #  privacy_statement_url:
+            #    - lang: en
+            #      text: "https://example.com/privacy-policy"
+            #  keywords:
+            #    - lang: en
+            #      text: ["Matrix", "Element"]
+            #  logo:
+            #    - lang: en
+            #      text: "https://example.com/logo.svg"
+            #      width: "200"
+            #      height: "80"
+
+            #organization:
+            #  name: Example com
+            #  display_name:
+            #    - ["Example co", "en"]
+            #  url: "http://example.com"
+
+            #contact_person:
+            #  - given_name: Bob
+            #    sur_name: "the Sysadmin"
+            #    email_address": ["admin@example.com"]
+            #    contact_type": technical
 
           # Instead of putting the config inline as above, you can specify a
           # separate pysaml2 configuration file:
@@ -350,6 +385,14 @@ class SAML2Config(Config):
           #    value: "staff"
           #  - attribute: department
           #    value: "sales"
+
+          # If the metadata XML contains multiple IdP entities then the `idp_entityid`
+          # option must be set to the entity to redirect users to.
+          #
+          # Most deployments only have a single IdP entity and so should omit this
+          # option.
+          #
+          #idp_entityid: 'https://our_idp/entityid'
         """ % {
             "config_dir_path": config_dir_path
         }
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 9a5c7cb0ab..61335595ff 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -39,7 +39,7 @@ logger = logging.Logger(__name__)
 # in the list.
 DEFAULT_BIND_ADDRESSES = ["::", "0.0.0.0"]
 
-DEFAULT_ROOM_VERSION = "5"
+DEFAULT_ROOM_VERSION = "6"
 
 ROOM_COMPLEXITY_TOO_GREAT = (
     "Your homeserver is unable to join rooms this large or complex. "
diff --git a/synapse/config/tls.py b/synapse/config/tls.py
index 9ddb8b546b..ad37b93c02 100644
--- a/synapse/config/tls.py
+++ b/synapse/config/tls.py
@@ -18,7 +18,7 @@ import os
 import warnings
 from datetime import datetime
 from hashlib import sha256
-from typing import List
+from typing import List, Optional
 
 from unpaddedbase64 import encode_base64
 
@@ -177,8 +177,8 @@ class TlsConfig(Config):
             "use_insecure_ssl_client_just_for_testing_do_not_use"
         )
 
-        self.tls_certificate = None
-        self.tls_private_key = None
+        self.tls_certificate = None  # type: Optional[crypto.X509]
+        self.tls_private_key = None  # type: Optional[crypto.PKey]
 
     def is_disk_cert_valid(self, allow_self_signed=True):
         """
@@ -226,12 +226,12 @@ class TlsConfig(Config):
         days_remaining = (expires_on - now).days
         return days_remaining
 
-    def read_certificate_from_disk(self, require_cert_and_key):
+    def read_certificate_from_disk(self, require_cert_and_key: bool):
         """
         Read the certificates and private key from disk.
 
         Args:
-            require_cert_and_key (bool): set to True to throw an error if the certificate
+            require_cert_and_key: set to True to throw an error if the certificate
                 and key file are not given
         """
         if require_cert_and_key:
@@ -479,13 +479,13 @@ class TlsConfig(Config):
             }
         )
 
-    def read_tls_certificate(self):
+    def read_tls_certificate(self) -> crypto.X509:
         """Reads the TLS certificate from the configured file, and returns it
 
         Also checks if it is self-signed, and warns if so
 
         Returns:
-            OpenSSL.crypto.X509: the certificate
+            The certificate
         """
         cert_path = self.tls_certificate_file
         logger.info("Loading TLS certificate from %s", cert_path)
@@ -504,11 +504,11 @@ class TlsConfig(Config):
 
         return cert
 
-    def read_tls_private_key(self):
+    def read_tls_private_key(self) -> crypto.PKey:
         """Reads the TLS private key from the configured file, and returns it
 
         Returns:
-            OpenSSL.crypto.PKey: the private key
+            The private key
         """
         private_key_path = self.tls_private_key_file
         logger.info("Loading TLS key from %s", private_key_path)
diff --git a/synapse/config/tracer.py b/synapse/config/tracer.py
index 8be1346113..0c1a854f09 100644
--- a/synapse/config/tracer.py
+++ b/synapse/config/tracer.py
@@ -67,7 +67,7 @@ class TracerConfig(Config):
             # This is a list of regexes which are matched against the server_name of the
             # homeserver.
             #
-            # By defult, it is empty, so no servers are matched.
+            # By default, it is empty, so no servers are matched.
             #
             #homeserver_whitelist:
             #  - ".*"
diff --git a/synapse/config/workers.py b/synapse/config/workers.py
index f23e42cdf9..57ab097eba 100644
--- a/synapse/config/workers.py
+++ b/synapse/config/workers.py
@@ -132,6 +132,19 @@ class WorkerConfig(Config):
 
         self.events_shard_config = ShardedWorkerHandlingConfig(self.writers.events)
 
+        # Whether this worker should run background tasks or not.
+        #
+        # As a note for developers, the background tasks guarded by this should
+        # be able to run on only a single instance (meaning that they don't
+        # depend on any in-memory state of a particular worker).
+        #
+        # No effort is made to ensure only a single instance of these tasks is
+        # running.
+        background_tasks_instance = config.get("run_background_tasks_on") or "master"
+        self.run_background_tasks = (
+            self.worker_name is None and background_tasks_instance == "master"
+        ) or self.worker_name == background_tasks_instance
+
     def generate_config_section(self, config_dir_path, server_name, **kwargs):
         return """\
         ## Workers ##
@@ -167,6 +180,11 @@ class WorkerConfig(Config):
         #stream_writers:
         #  events: worker1
         #  typing: worker1
+
+        # The worker that is used to run background tasks (e.g. cleaning up expired
+        # data). If not provided this defaults to the main process.
+        #
+        #run_background_tasks_on: worker1
         """
 
     def read_arguments(self, args):
diff --git a/synapse/crypto/context_factory.py b/synapse/crypto/context_factory.py
index 79668a402e..57fd426e87 100644
--- a/synapse/crypto/context_factory.py
+++ b/synapse/crypto/context_factory.py
@@ -149,7 +149,7 @@ class FederationPolicyForHTTPS:
         return SSLClientConnectionCreator(host, ssl_context, should_verify)
 
     def creatorForNetloc(self, hostname, port):
-        """Implements the IPolicyForHTTPS interace so that this can be passed
+        """Implements the IPolicyForHTTPS interface so that this can be passed
         directly to agents.
         """
         return self.get_options(hostname)
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index 8c907ad596..56f8dc9caf 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -446,6 +446,8 @@ def check_redaction(
 
     if room_version_obj.event_format == EventFormatVersions.V1:
         redacter_domain = get_domain_from_id(event.event_id)
+        if not isinstance(event.redacts, str):
+            return False
         redactee_domain = get_domain_from_id(event.redacts)
         if redacter_domain == redactee_domain:
             return True
diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index dc49df0812..8028663fa8 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -59,7 +59,7 @@ class DictProperty:
             #
             # To exclude the KeyError from the traceback, we explicitly
             # 'raise from e1.__context__' (which is better than 'raise from None',
-            # becuase that would omit any *earlier* exceptions).
+            # because that would omit any *earlier* exceptions).
             #
             raise AttributeError(
                 "'%s' has no '%s' property" % (type(instance), self.key)
@@ -97,13 +97,16 @@ class DefaultDictProperty(DictProperty):
 
 
 class _EventInternalMetadata:
-    __slots__ = ["_dict"]
+    __slots__ = ["_dict", "stream_ordering"]
 
     def __init__(self, internal_metadata_dict: JsonDict):
         # we have to copy the dict, because it turns out that the same dict is
         # reused. TODO: fix that
         self._dict = dict(internal_metadata_dict)
 
+        # the stream ordering of this event. None, until it has been persisted.
+        self.stream_ordering = None  # type: Optional[int]
+
     outlier = DictProperty("outlier")  # type: bool
     out_of_band_membership = DictProperty("out_of_band_membership")  # type: bool
     send_on_behalf_of = DictProperty("send_on_behalf_of")  # type: str
@@ -113,7 +116,6 @@ class _EventInternalMetadata:
     redacted = DictProperty("redacted")  # type: bool
     txn_id = DictProperty("txn_id")  # type: str
     token_id = DictProperty("token_id")  # type: str
-    stream_ordering = DictProperty("stream_ordering")  # type: int
 
     # XXX: These are set by StreamWorkerStore._set_before_and_after.
     # I'm pretty sure that these are never persisted to the database, so shouldn't
@@ -310,6 +312,12 @@ class EventBase(metaclass=abc.ABCMeta):
         """
         return [e for e, _ in self.auth_events]
 
+    def freeze(self):
+        """'Freeze' the event dict, so it cannot be modified by accident"""
+
+        # this will be a no-op if the event dict is already frozen.
+        self._dict = freeze(self._dict)
+
 
 class FrozenEvent(EventBase):
     format_version = EventFormatVersions.V1  # All events of this type are V1
@@ -360,7 +368,7 @@ class FrozenEvent(EventBase):
         return self.__repr__()
 
     def __repr__(self):
-        return "<FrozenEvent event_id='%s', type='%s', state_key='%s'>" % (
+        return "<FrozenEvent event_id=%r, type=%r, state_key=%r>" % (
             self.get("event_id", None),
             self.get("type", None),
             self.get("state_key", None),
@@ -443,7 +451,7 @@ class FrozenEventV2(EventBase):
         return self.__repr__()
 
     def __repr__(self):
-        return "<%s event_id='%s', type='%s', state_key='%s'>" % (
+        return "<%s event_id=%r, type=%r, state_key=%r>" % (
             self.__class__.__name__,
             self.event_id,
             self.get("type", None),
diff --git a/synapse/events/builder.py b/synapse/events/builder.py
index b6c47be646..07df258e6e 100644
--- a/synapse/events/builder.py
+++ b/synapse/events/builder.py
@@ -97,32 +97,37 @@ class EventBuilder:
     def is_state(self):
         return self._state_key is not None
 
-    async def build(self, prev_event_ids: List[str]) -> EventBase:
+    async def build(
+        self, prev_event_ids: List[str], auth_event_ids: Optional[List[str]],
+    ) -> EventBase:
         """Transform into a fully signed and hashed event
 
         Args:
             prev_event_ids: The event IDs to use as the prev events
+            auth_event_ids: The event IDs to use as the auth events.
+                Should normally be set to None, which will cause them to be calculated
+                based on the room state at the prev_events.
 
         Returns:
             The signed and hashed event.
         """
-
-        state_ids = await self._state.get_current_state_ids(
-            self.room_id, prev_event_ids
-        )
-        auth_ids = self._auth.compute_auth_events(self, state_ids)
+        if auth_event_ids is None:
+            state_ids = await self._state.get_current_state_ids(
+                self.room_id, prev_event_ids
+            )
+            auth_event_ids = self._auth.compute_auth_events(self, state_ids)
 
         format_version = self.room_version.event_format
         if format_version == EventFormatVersions.V1:
             # The types of auth/prev events changes between event versions.
             auth_events = await self._store.add_event_hashes(
-                auth_ids
+                auth_event_ids
             )  # type: Union[List[str], List[Tuple[str, Dict[str, str]]]]
             prev_events = await self._store.add_event_hashes(
                 prev_event_ids
             )  # type: Union[List[str], List[Tuple[str, Dict[str, str]]]]
         else:
-            auth_events = auth_ids
+            auth_events = auth_event_ids
             prev_events = prev_event_ids
 
         old_depth = await self._store.get_max_depth_of(prev_event_ids)
diff --git a/synapse/events/spamcheck.py b/synapse/events/spamcheck.py
index d141519ec4..4404ffffe9 100644
--- a/synapse/events/spamcheck.py
+++ b/synapse/events/spamcheck.py
@@ -15,26 +15,26 @@
 # limitations under the License.
 
 import inspect
-from typing import Any, Dict, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
 
-from synapse.spam_checker_api import RegistrationBehaviour, SpamCheckerApi
+from synapse.spam_checker_api import RegistrationBehaviour
 from synapse.types import Collection
 
-MYPY = False
-if MYPY:
+if TYPE_CHECKING:
+    import synapse.events
     import synapse.server
 
 
 class SpamChecker:
     def __init__(self, hs: "synapse.server.HomeServer"):
         self.spam_checkers = []  # type: List[Any]
+        api = hs.get_module_api()
 
         for module, config in hs.config.spam_checkers:
             # Older spam checkers don't accept the `api` argument, so we
             # try and detect support.
             spam_args = inspect.getfullargspec(module)
             if "api" in spam_args.args:
-                api = SpamCheckerApi(hs)
                 self.spam_checkers.append(module(config=config, api=api))
             else:
                 self.spam_checkers.append(module(config=config))
diff --git a/synapse/events/third_party_rules.py b/synapse/events/third_party_rules.py
index 1ca77519d5..77fbd3f68a 100644
--- a/synapse/events/third_party_rules.py
+++ b/synapse/events/third_party_rules.py
@@ -12,11 +12,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Callable
+
+from typing import Callable, Union
 
 from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
-from synapse.module_api import ModuleApi
 from synapse.types import Requester, StateMap
 
 
@@ -40,20 +40,25 @@ class ThirdPartyEventRules:
 
         if module is not None:
             self.third_party_rules = module(
-                config=config, module_api=ModuleApi(hs, hs.get_auth_handler()),
+                config=config, module_api=hs.get_module_api(),
             )
 
     async def check_event_allowed(
         self, event: EventBase, context: EventContext
-    ) -> bool:
+    ) -> Union[bool, dict]:
         """Check if a provided event should be allowed in the given context.
 
+        The module can return:
+            * True: the event is allowed.
+            * False: the event is not allowed, and should be rejected with M_FORBIDDEN.
+            * a dict: replacement event data.
+
         Args:
             event: The event to be checked.
             context: The context of the event.
 
         Returns:
-            True if the event should be allowed, False if not.
+            The result from the ThirdPartyRules module, as above
         """
         if self.third_party_rules is None:
             return True
@@ -61,12 +66,15 @@ class ThirdPartyEventRules:
         prev_state_ids = await context.get_prev_state_ids()
 
         # Retrieve the state events from the database.
-        state_events = {}
-        for key, event_id in prev_state_ids.items():
-            state_events[key] = await self.store.get_event(event_id, allow_none=True)
+        events = await self.store.get_events(prev_state_ids.values())
+        state_events = {(ev.type, ev.state_key): ev for ev in events.values()}
 
-        ret = await self.third_party_rules.check_event_allowed(event, state_events)
-        return ret
+        # Ensure that the event is frozen, to make sure that the module is not tempted
+        # to try to modify it. Any attempt to modify it at this point will invalidate
+        # the hashes and signatures.
+        event.freeze()
+
+        return await self.third_party_rules.check_event_allowed(event, state_events)
 
     async def on_create_room(
         self, requester: Requester, config: dict, is_requester_admin: bool
diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index 32c73d3413..14f7f1156f 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -49,6 +49,11 @@ def prune_event(event: EventBase) -> EventBase:
         pruned_event_dict, event.room_version, event.internal_metadata.get_dict()
     )
 
+    # copy the internal fields
+    pruned_event.internal_metadata.stream_ordering = (
+        event.internal_metadata.stream_ordering
+    )
+
     # Mark the event as redacted
     pruned_event.internal_metadata.redacted = True
 
@@ -175,7 +180,7 @@ def only_fields(dictionary, fields):
     in 'fields'.
 
     If there are no event fields specified then all fields are included.
-    The entries may include '.' charaters to indicate sub-fields.
+    The entries may include '.' characters to indicate sub-fields.
     So ['content.body'] will include the 'body' field of the 'content' object.
     A literal '.' character in a field name may be escaped using a '\'.
 
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
index 5f9af8529b..f8f3b1a31e 100644
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@@ -13,20 +13,26 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from typing import Union
+
 from synapse.api.constants import MAX_ALIAS_LENGTH, EventTypes, Membership
 from synapse.api.errors import Codes, SynapseError
 from synapse.api.room_versions import EventFormatVersions
+from synapse.config.homeserver import HomeServerConfig
+from synapse.events import EventBase
+from synapse.events.builder import EventBuilder
 from synapse.events.utils import validate_canonicaljson
+from synapse.federation.federation_server import server_matches_acl_event
 from synapse.types import EventID, RoomID, UserID
 
 
 class EventValidator:
-    def validate_new(self, event, config):
+    def validate_new(self, event: EventBase, config: HomeServerConfig):
         """Validates the event has roughly the right format
 
         Args:
-            event (FrozenEvent): The event to validate.
-            config (Config): The homeserver's configuration.
+            event: The event to validate.
+            config: The homeserver's configuration.
         """
         self.validate_builder(event)
 
@@ -76,12 +82,18 @@ class EventValidator:
         if event.type == EventTypes.Retention:
             self._validate_retention(event)
 
-    def _validate_retention(self, event):
+        if event.type == EventTypes.ServerACL:
+            if not server_matches_acl_event(config.server_name, event):
+                raise SynapseError(
+                    400, "Can't create an ACL event that denies the local server"
+                )
+
+    def _validate_retention(self, event: EventBase):
         """Checks that an event that defines the retention policy for a room respects the
         format enforced by the spec.
 
         Args:
-            event (FrozenEvent): The event to validate.
+            event: The event to validate.
         """
         if not event.is_state():
             raise SynapseError(code=400, msg="must be a state event")
@@ -116,13 +128,10 @@ class EventValidator:
                 errcode=Codes.BAD_JSON,
             )
 
-    def validate_builder(self, event):
+    def validate_builder(self, event: Union[EventBase, EventBuilder]):
         """Validates that the builder/event has roughly the right format. Only
         checks values that we expect a proto event to have, rather than all the
         fields an event would have
-
-        Args:
-            event (EventBuilder|FrozenEvent)
         """
 
         strings = ["room_id", "sender", "type"]
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 24329dd0e3..4b6ab470d0 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -22,7 +22,6 @@ from typing import (
     Callable,
     Dict,
     List,
-    Match,
     Optional,
     Tuple,
     Union,
@@ -50,6 +49,7 @@ from synapse.federation.federation_base import FederationBase, event_from_pdu_js
 from synapse.federation.persistence import TransactionActions
 from synapse.federation.units import Edu, Transaction
 from synapse.http.endpoint import parse_server_name
+from synapse.http.servlet import assert_params_in_dict
 from synapse.logging.context import (
     make_deferred_yieldable,
     nested_logging_context,
@@ -100,10 +100,15 @@ class FederationServer(FederationBase):
         super().__init__(hs)
 
         self.auth = hs.get_auth()
-        self.handler = hs.get_handlers().federation_handler
+        self.handler = hs.get_federation_handler()
         self.state = hs.get_state_handler()
 
         self.device_handler = hs.get_device_handler()
+
+        # Ensure the following handlers are loaded since they register callbacks
+        # with FederationHandlerRegistry.
+        hs.get_directory_handler()
+
         self._federation_ratelimiter = hs.get_federation_ratelimiter()
 
         self._server_linearizer = Linearizer("fed_server")
@@ -112,7 +117,7 @@ class FederationServer(FederationBase):
         # We cache results for transaction with the same ID
         self._transaction_resp_cache = ResponseCache(
             hs, "fed_txn_handler", timeout_ms=30000
-        )
+        )  # type: ResponseCache[Tuple[str, str]]
 
         self.transaction_actions = TransactionActions(self.store)
 
@@ -120,10 +125,12 @@ class FederationServer(FederationBase):
 
         # We cache responses to state queries, as they take a while and often
         # come in waves.
-        self._state_resp_cache = ResponseCache(hs, "state_resp", timeout_ms=30000)
+        self._state_resp_cache = ResponseCache(
+            hs, "state_resp", timeout_ms=30000
+        )  # type: ResponseCache[Tuple[str, str]]
         self._state_ids_resp_cache = ResponseCache(
             hs, "state_ids_resp", timeout_ms=30000
-        )
+        )  # type: ResponseCache[Tuple[str, str]]
 
         self._federation_metrics_domains = (
             hs.get_config().federation.federation_metrics_domains
@@ -385,7 +392,7 @@ class FederationServer(FederationBase):
             TRANSACTION_CONCURRENCY_LIMIT,
         )
 
-    async def on_context_state_request(
+    async def on_room_state_request(
         self, origin: str, room_id: str, event_id: str
     ) -> Tuple[int, Dict[str, Any]]:
         origin_host, _ = parse_server_name(origin)
@@ -508,11 +515,12 @@ class FederationServer(FederationBase):
         return {"event": ret_pdu.get_pdu_json(time_now)}
 
     async def on_send_join_request(
-        self, origin: str, content: JsonDict, room_id: str
+        self, origin: str, content: JsonDict
     ) -> Dict[str, Any]:
         logger.debug("on_send_join_request: content: %s", content)
 
-        room_version = await self.store.get_room_version(room_id)
+        assert_params_in_dict(content, ["room_id"])
+        room_version = await self.store.get_room_version(content["room_id"])
         pdu = event_from_pdu_json(content, room_version)
 
         origin_host, _ = parse_server_name(origin)
@@ -541,12 +549,11 @@ class FederationServer(FederationBase):
         time_now = self._clock.time_msec()
         return {"event": pdu.get_pdu_json(time_now), "room_version": room_version}
 
-    async def on_send_leave_request(
-        self, origin: str, content: JsonDict, room_id: str
-    ) -> dict:
+    async def on_send_leave_request(self, origin: str, content: JsonDict) -> dict:
         logger.debug("on_send_leave_request: content: %s", content)
 
-        room_version = await self.store.get_room_version(room_id)
+        assert_params_in_dict(content, ["room_id"])
+        room_version = await self.store.get_room_version(content["room_id"])
         pdu = event_from_pdu_json(content, room_version)
 
         origin_host, _ = parse_server_name(origin)
@@ -742,12 +749,8 @@ class FederationServer(FederationBase):
         )
         return ret
 
-    async def on_exchange_third_party_invite_request(
-        self, room_id: str, event_dict: Dict
-    ):
-        ret = await self.handler.on_exchange_third_party_invite_request(
-            room_id, event_dict
-        )
+    async def on_exchange_third_party_invite_request(self, event_dict: Dict):
+        ret = await self.handler.on_exchange_third_party_invite_request(event_dict)
         return ret
 
     async def check_server_matches_acl(self, server_name: str, room_id: str):
@@ -825,14 +828,14 @@ def server_matches_acl_event(server_name: str, acl_event: EventBase) -> bool:
     return False
 
 
-def _acl_entry_matches(server_name: str, acl_entry: str) -> Match:
+def _acl_entry_matches(server_name: str, acl_entry: Any) -> bool:
     if not isinstance(acl_entry, str):
         logger.warning(
             "Ignoring non-str ACL entry '%s' (is %s)", acl_entry, type(acl_entry)
         )
         return False
     regex = glob_to_regex(acl_entry)
-    return regex.match(server_name)
+    return bool(regex.match(server_name))
 
 
 class FederationHandlerRegistry:
@@ -862,7 +865,7 @@ class FederationHandlerRegistry:
         self._edu_type_to_instance = {}  # type: Dict[str, str]
 
     def register_edu_handler(
-        self, edu_type: str, handler: Callable[[str, dict], Awaitable[None]]
+        self, edu_type: str, handler: Callable[[str, JsonDict], Awaitable[None]]
     ):
         """Sets the handler callable that will be used to handle an incoming
         federation EDU of the given type.
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index 8e46957d15..5f1bf492c1 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -188,7 +188,7 @@ class FederationRemoteSendQueue:
             for key in keys[:i]:
                 del self.edus[key]
 
-    def notify_new_events(self, current_id):
+    def notify_new_events(self, max_token):
         """As per FederationSender"""
         # We don't need to replicate this as it gets sent down a different
         # stream.
diff --git a/synapse/federation/sender/__init__.py b/synapse/federation/sender/__init__.py
index 8bb17b3a05..604cfd1935 100644
--- a/synapse/federation/sender/__init__.py
+++ b/synapse/federation/sender/__init__.py
@@ -40,7 +40,7 @@ from synapse.metrics import (
     events_processed_counter,
 )
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.types import ReadReceipt
+from synapse.types import ReadReceipt, RoomStreamToken
 from synapse.util.metrics import Measure, measure_func
 
 logger = logging.getLogger(__name__)
@@ -154,10 +154,15 @@ class FederationSender:
             self._per_destination_queues[destination] = queue
         return queue
 
-    def notify_new_events(self, current_id: int) -> None:
+    def notify_new_events(self, max_token: RoomStreamToken) -> None:
         """This gets called when we have some new events we might want to
         send out to other servers.
         """
+        # We just use the minimum stream ordering and ignore the vector clock
+        # component. This is safe to do as long as we *always* ignore the vector
+        # clock components.
+        current_id = max_token.stream
+
         self._last_poked_id = max(current_id, self._last_poked_id)
 
         if self._is_processing:
@@ -297,6 +302,8 @@ class FederationSender:
         sent_pdus_destination_dist_total.inc(len(destinations))
         sent_pdus_destination_dist_count.inc()
 
+        assert pdu.internal_metadata.stream_ordering
+
         # track the fact that we have a PDU for these destinations,
         # to allow us to perform catch-up later on if the remote is unreachable
         # for a while.
diff --git a/synapse/federation/sender/per_destination_queue.py b/synapse/federation/sender/per_destination_queue.py
index bc99af3fdd..db8e456fe8 100644
--- a/synapse/federation/sender/per_destination_queue.py
+++ b/synapse/federation/sender/per_destination_queue.py
@@ -158,6 +158,7 @@ class PerDestinationQueue:
             # yet know if we have anything to catch up (None)
             self._pending_pdus.append(pdu)
         else:
+            assert pdu.internal_metadata.stream_ordering
             self._catchup_last_skipped = pdu.internal_metadata.stream_ordering
 
         self.attempt_new_transaction()
@@ -361,6 +362,7 @@ class PerDestinationQueue:
                         last_successful_stream_ordering = (
                             final_pdu.internal_metadata.stream_ordering
                         )
+                        assert last_successful_stream_ordering
                         await self._store.set_destination_last_successful_stream_ordering(
                             self._destination, last_successful_stream_ordering
                         )
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 7b4baddbf8..a9b73d713a 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -155,7 +155,7 @@ class Authenticator:
         )
 
         logger.debug("Request from %s", origin)
-        request.authenticated_entity = origin
+        request.requester = origin
 
         # If we get a valid signed request from the other side, its probably
         # alive
@@ -441,13 +441,13 @@ class FederationEventServlet(BaseFederationServlet):
 
 
 class FederationStateV1Servlet(BaseFederationServlet):
-    PATH = "/state/(?P<context>[^/]*)/?"
+    PATH = "/state/(?P<room_id>[^/]*)/?"
 
-    # This is when someone asks for all data for a given context.
-    async def on_GET(self, origin, content, query, context):
-        return await self.handler.on_context_state_request(
+    # This is when someone asks for all data for a given room.
+    async def on_GET(self, origin, content, query, room_id):
+        return await self.handler.on_room_state_request(
             origin,
-            context,
+            room_id,
             parse_string_from_args(query, "event_id", None, required=False),
         )
 
@@ -464,16 +464,16 @@ class FederationStateIdsServlet(BaseFederationServlet):
 
 
 class FederationBackfillServlet(BaseFederationServlet):
-    PATH = "/backfill/(?P<context>[^/]*)/?"
+    PATH = "/backfill/(?P<room_id>[^/]*)/?"
 
-    async def on_GET(self, origin, content, query, context):
+    async def on_GET(self, origin, content, query, room_id):
         versions = [x.decode("ascii") for x in query[b"v"]]
         limit = parse_integer_from_args(query, "limit", None)
 
         if not limit:
             return 400, {"error": "Did not include limit param"}
 
-        return await self.handler.on_backfill_request(origin, context, versions, limit)
+        return await self.handler.on_backfill_request(origin, room_id, versions, limit)
 
 
 class FederationQueryServlet(BaseFederationServlet):
@@ -488,9 +488,9 @@ class FederationQueryServlet(BaseFederationServlet):
 
 
 class FederationMakeJoinServlet(BaseFederationServlet):
-    PATH = "/make_join/(?P<context>[^/]*)/(?P<user_id>[^/]*)"
+    PATH = "/make_join/(?P<room_id>[^/]*)/(?P<user_id>[^/]*)"
 
-    async def on_GET(self, origin, _content, query, context, user_id):
+    async def on_GET(self, origin, _content, query, room_id, user_id):
         """
         Args:
             origin (unicode): The authenticated server_name of the calling server
@@ -512,16 +512,16 @@ class FederationMakeJoinServlet(BaseFederationServlet):
             supported_versions = ["1"]
 
         content = await self.handler.on_make_join_request(
-            origin, context, user_id, supported_versions=supported_versions
+            origin, room_id, user_id, supported_versions=supported_versions
         )
         return 200, content
 
 
 class FederationMakeLeaveServlet(BaseFederationServlet):
-    PATH = "/make_leave/(?P<context>[^/]*)/(?P<user_id>[^/]*)"
+    PATH = "/make_leave/(?P<room_id>[^/]*)/(?P<user_id>[^/]*)"
 
-    async def on_GET(self, origin, content, query, context, user_id):
-        content = await self.handler.on_make_leave_request(origin, context, user_id)
+    async def on_GET(self, origin, content, query, room_id, user_id):
+        content = await self.handler.on_make_leave_request(origin, room_id, user_id)
         return 200, content
 
 
@@ -529,7 +529,7 @@ class FederationV1SendLeaveServlet(BaseFederationServlet):
     PATH = "/send_leave/(?P<room_id>[^/]*)/(?P<event_id>[^/]*)"
 
     async def on_PUT(self, origin, content, query, room_id, event_id):
-        content = await self.handler.on_send_leave_request(origin, content, room_id)
+        content = await self.handler.on_send_leave_request(origin, content)
         return 200, (200, content)
 
 
@@ -539,43 +539,43 @@ class FederationV2SendLeaveServlet(BaseFederationServlet):
     PREFIX = FEDERATION_V2_PREFIX
 
     async def on_PUT(self, origin, content, query, room_id, event_id):
-        content = await self.handler.on_send_leave_request(origin, content, room_id)
+        content = await self.handler.on_send_leave_request(origin, content)
         return 200, content
 
 
 class FederationEventAuthServlet(BaseFederationServlet):
-    PATH = "/event_auth/(?P<context>[^/]*)/(?P<event_id>[^/]*)"
+    PATH = "/event_auth/(?P<room_id>[^/]*)/(?P<event_id>[^/]*)"
 
-    async def on_GET(self, origin, content, query, context, event_id):
-        return await self.handler.on_event_auth(origin, context, event_id)
+    async def on_GET(self, origin, content, query, room_id, event_id):
+        return await self.handler.on_event_auth(origin, room_id, event_id)
 
 
 class FederationV1SendJoinServlet(BaseFederationServlet):
-    PATH = "/send_join/(?P<context>[^/]*)/(?P<event_id>[^/]*)"
+    PATH = "/send_join/(?P<room_id>[^/]*)/(?P<event_id>[^/]*)"
 
-    async def on_PUT(self, origin, content, query, context, event_id):
-        # TODO(paul): assert that context/event_id parsed from path actually
+    async def on_PUT(self, origin, content, query, room_id, event_id):
+        # TODO(paul): assert that room_id/event_id parsed from path actually
         #   match those given in content
-        content = await self.handler.on_send_join_request(origin, content, context)
+        content = await self.handler.on_send_join_request(origin, content)
         return 200, (200, content)
 
 
 class FederationV2SendJoinServlet(BaseFederationServlet):
-    PATH = "/send_join/(?P<context>[^/]*)/(?P<event_id>[^/]*)"
+    PATH = "/send_join/(?P<room_id>[^/]*)/(?P<event_id>[^/]*)"
 
     PREFIX = FEDERATION_V2_PREFIX
 
-    async def on_PUT(self, origin, content, query, context, event_id):
-        # TODO(paul): assert that context/event_id parsed from path actually
+    async def on_PUT(self, origin, content, query, room_id, event_id):
+        # TODO(paul): assert that room_id/event_id parsed from path actually
         #   match those given in content
-        content = await self.handler.on_send_join_request(origin, content, context)
+        content = await self.handler.on_send_join_request(origin, content)
         return 200, content
 
 
 class FederationV1InviteServlet(BaseFederationServlet):
-    PATH = "/invite/(?P<context>[^/]*)/(?P<event_id>[^/]*)"
+    PATH = "/invite/(?P<room_id>[^/]*)/(?P<event_id>[^/]*)"
 
-    async def on_PUT(self, origin, content, query, context, event_id):
+    async def on_PUT(self, origin, content, query, room_id, event_id):
         # We don't get a room version, so we have to assume its EITHER v1 or
         # v2. This is "fine" as the only difference between V1 and V2 is the
         # state resolution algorithm, and we don't use that for processing
@@ -590,12 +590,12 @@ class FederationV1InviteServlet(BaseFederationServlet):
 
 
 class FederationV2InviteServlet(BaseFederationServlet):
-    PATH = "/invite/(?P<context>[^/]*)/(?P<event_id>[^/]*)"
+    PATH = "/invite/(?P<room_id>[^/]*)/(?P<event_id>[^/]*)"
 
     PREFIX = FEDERATION_V2_PREFIX
 
-    async def on_PUT(self, origin, content, query, context, event_id):
-        # TODO(paul): assert that context/event_id parsed from path actually
+    async def on_PUT(self, origin, content, query, room_id, event_id):
+        # TODO(paul): assert that room_id/event_id parsed from path actually
         #   match those given in content
 
         room_version = content["room_version"]
@@ -617,9 +617,7 @@ class FederationThirdPartyInviteExchangeServlet(BaseFederationServlet):
     PATH = "/exchange_third_party_invite/(?P<room_id>[^/]*)"
 
     async def on_PUT(self, origin, content, query, room_id):
-        content = await self.handler.on_exchange_third_party_invite_request(
-            room_id, content
-        )
+        content = await self.handler.on_exchange_third_party_invite_request(content)
         return 200, content
 
 
diff --git a/synapse/groups/attestations.py b/synapse/groups/attestations.py
index a86b3debc5..41cf07cc88 100644
--- a/synapse/groups/attestations.py
+++ b/synapse/groups/attestations.py
@@ -22,7 +22,7 @@ attestations have a validity period so need to be periodically renewed.
 If a user leaves (or gets kicked out of) a group, either side can still use
 their attestation to "prove" their membership, until the attestation expires.
 Therefore attestations shouldn't be relied on to prove membership in important
-cases, but can for less important situtations, e.g. showing a users membership
+cases, but can for less important situations, e.g. showing a users membership
 of groups on their profile, showing flairs, etc.
 
 An attestation is a signed blob of json that looks like:
diff --git a/synapse/groups/groups_server.py b/synapse/groups/groups_server.py
index e5f85b472d..0d042cbfac 100644
--- a/synapse/groups/groups_server.py
+++ b/synapse/groups/groups_server.py
@@ -113,7 +113,7 @@ class GroupsServerWorkerHandler:
             entry = await self.room_list_handler.generate_room_entry(
                 room_id, len(joined_users), with_alias=False, allow_private=True
             )
-            entry = dict(entry)  # so we don't change whats cached
+            entry = dict(entry)  # so we don't change what's cached
             entry.pop("room_id", None)
 
             room_entry["profile"] = entry
@@ -550,7 +550,7 @@ class GroupsServerHandler(GroupsServerWorkerHandler):
                 group_id, room_id, is_public=is_public
             )
         else:
-            raise SynapseError(400, "Uknown config option")
+            raise SynapseError(400, "Unknown config option")
 
         return {}
 
diff --git a/synapse/handlers/__init__.py b/synapse/handlers/__init__.py
index 286f0054be..bfebb0f644 100644
--- a/synapse/handlers/__init__.py
+++ b/synapse/handlers/__init__.py
@@ -12,36 +12,3 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
-from .admin import AdminHandler
-from .directory import DirectoryHandler
-from .federation import FederationHandler
-from .identity import IdentityHandler
-from .search import SearchHandler
-
-
-class Handlers:
-
-    """ Deprecated. A collection of handlers.
-
-    At some point most of the classes whose name ended "Handler" were
-    accessed through this class.
-
-    However this makes it painful to unit test the handlers and to run cut
-    down versions of synapse that only use specific handlers because using a
-    single handler required creating all of the handlers. So some of the
-    handlers have been lifted out of the Handlers object and are now accessed
-    directly through the homeserver object itself.
-
-    Any new handlers should follow the new pattern of being accessed through
-    the homeserver object and should not be added to the Handlers object.
-
-    The remaining handlers should be moved out of the handlers object.
-    """
-
-    def __init__(self, hs):
-        self.federation_handler = FederationHandler(hs)
-        self.directory_handler = DirectoryHandler(hs)
-        self.admin_handler = AdminHandler(hs)
-        self.identity_handler = IdentityHandler(hs)
-        self.search_handler = SearchHandler(hs)
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index 0206320e96..bb81c0e81d 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import logging
+from typing import TYPE_CHECKING, Optional
 
 import synapse.state
 import synapse.storage
@@ -22,6 +23,9 @@ from synapse.api.constants import EventTypes, Membership
 from synapse.api.ratelimiting import Ratelimiter
 from synapse.types import UserID
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
@@ -30,11 +34,7 @@ class BaseHandler:
     Common base class for the event handlers.
     """
 
-    def __init__(self, hs):
-        """
-        Args:
-            hs (synapse.server.HomeServer):
-        """
+    def __init__(self, hs: "HomeServer"):
         self.store = hs.get_datastore()  # type: synapse.storage.DataStore
         self.auth = hs.get_auth()
         self.notifier = hs.get_notifier()
@@ -56,7 +56,7 @@ class BaseHandler:
                 clock=self.clock,
                 rate_hz=self.hs.config.rc_admin_redaction.per_second,
                 burst_count=self.hs.config.rc_admin_redaction.burst_count,
-            )
+            )  # type: Optional[Ratelimiter]
         else:
             self.admin_redaction_ratelimiter = None
 
@@ -127,15 +127,15 @@ class BaseHandler:
             if guest_access != "can_join":
                 if context:
                     current_state_ids = await context.get_current_state_ids()
-                    current_state = await self.store.get_events(
+                    current_state_dict = await self.store.get_events(
                         list(current_state_ids.values())
                     )
+                    current_state = list(current_state_dict.values())
                 else:
-                    current_state = await self.state_handler.get_current_state(
+                    current_state_map = await self.state_handler.get_current_state(
                         event.room_id
                     )
-
-                current_state = list(current_state.values())
+                    current_state = list(current_state_map.values())
 
                 logger.info("maybe_kick_guest_users %r", current_state)
                 await self.kick_guest_users(current_state)
@@ -169,7 +169,9 @@ class BaseHandler:
                 # and having homeservers have their own users leave keeps more
                 # of that decision-making and control local to the guest-having
                 # homeserver.
-                requester = synapse.types.create_requester(target_user, is_guest=True)
+                requester = synapse.types.create_requester(
+                    target_user, is_guest=True, authenticated_entity=self.server_name
+                )
                 handler = self.hs.get_room_member_handler()
                 await handler.update_membership(
                     requester,
diff --git a/synapse/handlers/account_data.py b/synapse/handlers/account_data.py
index 9112a0ab86..341135822e 100644
--- a/synapse/handlers/account_data.py
+++ b/synapse/handlers/account_data.py
@@ -12,16 +12,24 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from typing import TYPE_CHECKING, List, Tuple
+
+from synapse.types import JsonDict, UserID
+
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
 
 
 class AccountDataEventSource:
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         self.store = hs.get_datastore()
 
-    def get_current_key(self, direction="f"):
+    def get_current_key(self, direction: str = "f") -> int:
         return self.store.get_max_account_data_stream_id()
 
-    async def get_new_events(self, user, from_key, **kwargs):
+    async def get_new_events(
+        self, user: UserID, from_key: int, **kwargs
+    ) -> Tuple[List[JsonDict], int]:
         user_id = user.to_string()
         last_stream_id = from_key
 
diff --git a/synapse/handlers/account_validity.py b/synapse/handlers/account_validity.py
index 764ec1d8ca..ce97fa70d7 100644
--- a/synapse/handlers/account_validity.py
+++ b/synapse/handlers/account_validity.py
@@ -18,19 +18,25 @@ import email.utils
 import logging
 from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
-from typing import List, Optional, Tuple
+from typing import TYPE_CHECKING, List, Optional, Tuple
 
-from synapse.api.errors import StoreError
+from synapse.api.errors import StoreError, SynapseError
 from synapse.logging.context import make_deferred_yieldable
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import (
+    run_as_background_process,
+    wrap_as_background_process,
+)
 from synapse.types import UserID
 from synapse.util import stringutils
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
 class AccountValidityHandler:
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         self.hs = hs
         self.config = hs.config
         self.store = self.hs.get_datastore()
@@ -73,14 +79,8 @@ class AccountValidityHandler:
             self._raw_from = email.utils.parseaddr(self._from_string)[1]
 
             # Check the renewal emails to send and send them every 30min.
-            def send_emails():
-                # run as a background process to make sure that the database transactions
-                # have a logcontext to report to
-                return run_as_background_process(
-                    "send_renewals", self._send_renewal_emails
-                )
-
-            self.clock.looping_call(send_emails, 30 * 60 * 1000)
+            if hs.config.run_background_tasks:
+                self.clock.looping_call(self._send_renewal_emails, 30 * 60 * 1000)
 
         # Mark users as inactive when they expired. Check once every hour
         if self._account_validity_enabled:
@@ -94,7 +94,8 @@ class AccountValidityHandler:
 
             self.clock.looping_call(mark_expired_users_as_inactive, 60 * 60 * 1000)
 
-    async def _send_renewal_emails(self):
+    @wrap_as_background_process("send_renewals")
+    async def _send_renewal_emails(self) -> None:
         """Gets the list of users whose account is expiring in the amount of time
         configured in the ``renew_at`` parameter from the ``account_validity``
         configuration, and sends renewal emails to all of these users as long as they
@@ -108,11 +109,25 @@ class AccountValidityHandler:
                     user_id=user["user_id"], expiration_ts=user["expiration_ts_ms"]
                 )
 
-    async def send_renewal_email_to_user(self, user_id: str):
+    async def send_renewal_email_to_user(self, user_id: str) -> None:
+        """
+        Send a renewal email for a specific user.
+
+        Args:
+            user_id: The user ID to send a renewal email for.
+
+        Raises:
+            SynapseError if the user is not set to renew.
+        """
         expiration_ts = await self.store.get_expiration_ts_for_user(user_id)
+
+        # If this user isn't set to be expired, raise an error.
+        if expiration_ts is None:
+            raise SynapseError(400, "User has no expiration time: %s" % (user_id,))
+
         await self._send_renewal_email(user_id, expiration_ts)
 
-    async def _send_renewal_email(self, user_id: str, expiration_ts: int):
+    async def _send_renewal_email(self, user_id: str, expiration_ts: int) -> None:
         """Sends out a renewal email to every email address attached to the given user
         with a unique link allowing them to renew their account.
 
@@ -284,7 +299,7 @@ class AccountValidityHandler:
         self,
         user_id: str,
         expiration_ts: Optional[int] = None,
-        email_sent: Optional[bool] = False,
+        email_sent: bool = False,
         renewal_token: Optional[str] = None,
     ) -> int:
         """Renews the account attached to a given user by pushing back the
diff --git a/synapse/handlers/admin.py b/synapse/handlers/admin.py
index 1ce2091b46..a703944543 100644
--- a/synapse/handlers/admin.py
+++ b/synapse/handlers/admin.py
@@ -88,7 +88,7 @@ class AdminHandler(BaseHandler):
 
         # We only try and fetch events for rooms the user has been in. If
         # they've been e.g. invited to a room without joining then we handle
-        # those seperately.
+        # those separately.
         rooms_user_has_been_in = await self.store.get_rooms_user_has_been_in(user_id)
 
         for index, room in enumerate(rooms):
@@ -226,7 +226,7 @@ class ExfiltrationWriter:
         """
 
     def finished(self):
-        """Called when all data has succesfully been exported and written.
+        """Called when all data has successfully been exported and written.
 
         This functions return value is passed to the caller of
         `export_user_data`.
diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index 9d4e87dad6..5c6458eb52 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -12,8 +12,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import logging
+from typing import TYPE_CHECKING, Dict, List, Optional, Union
 
 from prometheus_client import Counter
 
@@ -21,21 +21,32 @@ from twisted.internet import defer
 
 import synapse
 from synapse.api.constants import EventTypes
+from synapse.appservice import ApplicationService
+from synapse.events import EventBase
+from synapse.handlers.presence import format_user_presence_state
 from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.metrics import (
     event_processing_loop_counter,
     event_processing_loop_room_count,
 )
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import (
+    run_as_background_process,
+    wrap_as_background_process,
+)
+from synapse.storage.databases.main.directory import RoomAliasMapping
+from synapse.types import Collection, JsonDict, RoomAlias, RoomStreamToken, UserID
 from synapse.util.metrics import Measure
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 events_processed_counter = Counter("synapse_handlers_appservice_events_processed", "")
 
 
 class ApplicationServicesHandler:
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         self.store = hs.get_datastore()
         self.is_mine_id = hs.is_mine_id
         self.appservice_api = hs.get_application_service_api()
@@ -43,19 +54,22 @@ class ApplicationServicesHandler:
         self.started_scheduler = False
         self.clock = hs.get_clock()
         self.notify_appservices = hs.config.notify_appservices
+        self.event_sources = hs.get_event_sources()
 
         self.current_max = 0
         self.is_processing = False
 
-    async def notify_interested_services(self, current_id):
+    def notify_interested_services(self, max_token: RoomStreamToken):
         """Notifies (pushes) all application services interested in this event.
 
         Pushing is done asynchronously, so this method won't block for any
         prolonged length of time.
-
-        Args:
-            current_id(int): The current maximum ID.
         """
+        # We just use the minimum stream ordering and ignore the vector clock
+        # component. This is safe to do as long as we *always* ignore the vector
+        # clock components.
+        current_id = max_token.stream
+
         services = self.store.get_app_services()
         if not services or not self.notify_appservices:
             return
@@ -64,6 +78,12 @@ class ApplicationServicesHandler:
         if self.is_processing:
             return
 
+        # We only start a new background process if necessary rather than
+        # optimistically (to cut down on overhead).
+        self._notify_interested_services(max_token)
+
+    @wrap_as_background_process("notify_interested_services")
+    async def _notify_interested_services(self, max_token: RoomStreamToken):
         with Measure(self.clock, "notify_interested_services"):
             self.is_processing = True
             try:
@@ -79,7 +99,7 @@ class ApplicationServicesHandler:
                     if not events:
                         break
 
-                    events_by_room = {}
+                    events_by_room = {}  # type: Dict[str, List[EventBase]]
                     for event in events:
                         events_by_room.setdefault(event.room_id, []).append(event)
 
@@ -158,11 +178,139 @@ class ApplicationServicesHandler:
             finally:
                 self.is_processing = False
 
-    async def query_user_exists(self, user_id):
+    def notify_interested_services_ephemeral(
+        self,
+        stream_key: str,
+        new_token: Optional[int],
+        users: Collection[Union[str, UserID]] = [],
+    ):
+        """This is called by the notifier in the background
+        when a ephemeral event handled by the homeserver.
+
+        This will determine which appservices
+        are interested in the event, and submit them.
+
+        Events will only be pushed to appservices
+        that have opted into ephemeral events
+
+        Args:
+            stream_key: The stream the event came from.
+            new_token: The latest stream token
+            users: The user(s) involved with the event.
+        """
+        if not self.notify_appservices:
+            return
+
+        if stream_key not in ("typing_key", "receipt_key", "presence_key"):
+            return
+
+        services = [
+            service
+            for service in self.store.get_app_services()
+            if service.supports_ephemeral
+        ]
+        if not services:
+            return
+
+        # We only start a new background process if necessary rather than
+        # optimistically (to cut down on overhead).
+        self._notify_interested_services_ephemeral(
+            services, stream_key, new_token, users
+        )
+
+    @wrap_as_background_process("notify_interested_services_ephemeral")
+    async def _notify_interested_services_ephemeral(
+        self,
+        services: List[ApplicationService],
+        stream_key: str,
+        new_token: Optional[int],
+        users: Collection[Union[str, UserID]],
+    ):
+        logger.debug("Checking interested services for %s" % (stream_key))
+        with Measure(self.clock, "notify_interested_services_ephemeral"):
+            for service in services:
+                # Only handle typing if we have the latest token
+                if stream_key == "typing_key" and new_token is not None:
+                    events = await self._handle_typing(service, new_token)
+                    if events:
+                        self.scheduler.submit_ephemeral_events_for_as(service, events)
+                    # We don't persist the token for typing_key for performance reasons
+                elif stream_key == "receipt_key":
+                    events = await self._handle_receipts(service)
+                    if events:
+                        self.scheduler.submit_ephemeral_events_for_as(service, events)
+                    await self.store.set_type_stream_id_for_appservice(
+                        service, "read_receipt", new_token
+                    )
+                elif stream_key == "presence_key":
+                    events = await self._handle_presence(service, users)
+                    if events:
+                        self.scheduler.submit_ephemeral_events_for_as(service, events)
+                    await self.store.set_type_stream_id_for_appservice(
+                        service, "presence", new_token
+                    )
+
+    async def _handle_typing(
+        self, service: ApplicationService, new_token: int
+    ) -> List[JsonDict]:
+        typing_source = self.event_sources.sources["typing"]
+        # Get the typing events from just before current
+        typing, _ = await typing_source.get_new_events_as(
+            service=service,
+            # For performance reasons, we don't persist the previous
+            # token in the DB and instead fetch the latest typing information
+            # for appservices.
+            from_key=new_token - 1,
+        )
+        return typing
+
+    async def _handle_receipts(self, service: ApplicationService) -> List[JsonDict]:
+        from_key = await self.store.get_type_stream_id_for_appservice(
+            service, "read_receipt"
+        )
+        receipts_source = self.event_sources.sources["receipt"]
+        receipts, _ = await receipts_source.get_new_events_as(
+            service=service, from_key=from_key
+        )
+        return receipts
+
+    async def _handle_presence(
+        self, service: ApplicationService, users: Collection[Union[str, UserID]]
+    ) -> List[JsonDict]:
+        events = []  # type: List[JsonDict]
+        presence_source = self.event_sources.sources["presence"]
+        from_key = await self.store.get_type_stream_id_for_appservice(
+            service, "presence"
+        )
+        for user in users:
+            if isinstance(user, str):
+                user = UserID.from_string(user)
+
+            interested = await service.is_interested_in_presence(user, self.store)
+            if not interested:
+                continue
+            presence_events, _ = await presence_source.get_new_events(
+                user=user, service=service, from_key=from_key,
+            )
+            time_now = self.clock.time_msec()
+            events.extend(
+                {
+                    "type": "m.presence",
+                    "sender": event.user_id,
+                    "content": format_user_presence_state(
+                        event, time_now, include_user_id=False
+                    ),
+                }
+                for event in presence_events
+            )
+
+        return events
+
+    async def query_user_exists(self, user_id: str) -> bool:
         """Check if any application service knows this user_id exists.
 
         Args:
-            user_id(str): The user to query if they exist on any AS.
+            user_id: The user to query if they exist on any AS.
         Returns:
             True if this user exists on at least one application service.
         """
@@ -173,11 +321,13 @@ class ApplicationServicesHandler:
                 return True
         return False
 
-    async def query_room_alias_exists(self, room_alias):
+    async def query_room_alias_exists(
+        self, room_alias: RoomAlias
+    ) -> Optional[RoomAliasMapping]:
         """Check if an application service knows this room alias exists.
 
         Args:
-            room_alias(RoomAlias): The room alias to query.
+            room_alias: The room alias to query.
         Returns:
             namedtuple: with keys "room_id" and "servers" or None if no
             association can be found.
@@ -193,10 +343,13 @@ class ApplicationServicesHandler:
             )
             if is_known_alias:
                 # the alias exists now so don't query more ASes.
-                result = await self.store.get_association_from_room_alias(room_alias)
-                return result
+                return await self.store.get_association_from_room_alias(room_alias)
 
-    async def query_3pe(self, kind, protocol, fields):
+        return None
+
+    async def query_3pe(
+        self, kind: str, protocol: str, fields: Dict[bytes, List[bytes]]
+    ) -> List[JsonDict]:
         services = self._get_services_for_3pn(protocol)
 
         results = await make_deferred_yieldable(
@@ -218,9 +371,11 @@ class ApplicationServicesHandler:
 
         return ret
 
-    async def get_3pe_protocols(self, only_protocol=None):
+    async def get_3pe_protocols(
+        self, only_protocol: Optional[str] = None
+    ) -> Dict[str, JsonDict]:
         services = self.store.get_app_services()
-        protocols = {}
+        protocols = {}  # type: Dict[str, List[JsonDict]]
 
         # Collect up all the individual protocol responses out of the ASes
         for s in services:
@@ -236,7 +391,7 @@ class ApplicationServicesHandler:
                 if info is not None:
                     protocols[p].append(info)
 
-        def _merge_instances(infos):
+        def _merge_instances(infos: List[JsonDict]) -> JsonDict:
             if not infos:
                 return {}
 
@@ -251,19 +406,17 @@ class ApplicationServicesHandler:
 
             return combined
 
-        for p in protocols.keys():
-            protocols[p] = _merge_instances(protocols[p])
+        return {p: _merge_instances(protocols[p]) for p in protocols.keys()}
 
-        return protocols
-
-    async def _get_services_for_event(self, event):
+    async def _get_services_for_event(
+        self, event: EventBase
+    ) -> List[ApplicationService]:
         """Retrieve a list of application services interested in this event.
 
         Args:
-            event(Event): The event to check. Can be None if alias_list is not.
+            event: The event to check. Can be None if alias_list is not.
         Returns:
-            list<ApplicationService>: A list of services interested in this
-            event based on the service regex.
+            A list of services interested in this event based on the service regex.
         """
         services = self.store.get_app_services()
 
@@ -277,17 +430,15 @@ class ApplicationServicesHandler:
 
         return interested_list
 
-    def _get_services_for_user(self, user_id):
+    def _get_services_for_user(self, user_id: str) -> List[ApplicationService]:
         services = self.store.get_app_services()
-        interested_list = [s for s in services if (s.is_interested_in_user(user_id))]
-        return interested_list
+        return [s for s in services if (s.is_interested_in_user(user_id))]
 
-    def _get_services_for_3pn(self, protocol):
+    def _get_services_for_3pn(self, protocol: str) -> List[ApplicationService]:
         services = self.store.get_app_services()
-        interested_list = [s for s in services if s.is_interested_in_protocol(protocol)]
-        return interested_list
+        return [s for s in services if s.is_interested_in_protocol(protocol)]
 
-    async def _is_unknown_user(self, user_id):
+    async def _is_unknown_user(self, user_id: str) -> bool:
         if not self.is_mine_id(user_id):
             # we don't know if they are unknown or not since it isn't one of our
             # users. We can't poke ASes.
@@ -302,9 +453,8 @@ class ApplicationServicesHandler:
         service_list = [s for s in services if s.sender == user_id]
         return len(service_list) == 0
 
-    async def _check_user_exists(self, user_id):
+    async def _check_user_exists(self, user_id: str) -> bool:
         unknown_user = await self._is_unknown_user(user_id)
         if unknown_user:
-            exists = await self.query_user_exists(user_id)
-            return exists
+            return await self.query_user_exists(user_id)
         return True
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 8770e43635..c7dc07008a 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2014 - 2016 OpenMarket Ltd
 # Copyright 2017 Vector Creations Ltd
+# Copyright 2019 - 2020 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -18,10 +19,21 @@ import logging
 import time
 import unicodedata
 import urllib.parse
-from typing import Any, Callable, Dict, Iterable, List, Optional, Tuple, Union
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    Dict,
+    Iterable,
+    List,
+    Mapping,
+    Optional,
+    Tuple,
+    Union,
+)
 
 import attr
-import bcrypt  # type: ignore[import]
+import bcrypt
 import pymacaroons
 
 from synapse.api.constants import LoginType
@@ -49,6 +61,9 @@ from synapse.util.threepids import canonicalise_email
 
 from ._base import BaseHandler
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
@@ -149,11 +164,7 @@ class SsoLoginExtraAttributes:
 class AuthHandler(BaseHandler):
     SESSION_EXPIRE_MS = 48 * 60 * 60 * 1000
 
-    def __init__(self, hs):
-        """
-        Args:
-            hs (synapse.server.HomeServer):
-        """
+    def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
 
         self.checkers = {}  # type: Dict[str, UserInteractiveAuthChecker]
@@ -164,13 +175,20 @@ class AuthHandler(BaseHandler):
 
         self.bcrypt_rounds = hs.config.bcrypt_rounds
 
+        # we can't use hs.get_module_api() here, because to do so will create an
+        # import loop.
+        #
+        # TODO: refactor this class to separate the lower-level stuff that
+        #   ModuleApi can use from the higher-level stuff that uses ModuleApi, as
+        #   better way to break the loop
         account_handler = ModuleApi(hs, self)
+
         self.password_providers = [
-            module(config=config, account_handler=account_handler)
+            PasswordProvider.load(module, config, account_handler)
             for module, config in hs.config.password_providers
         ]
 
-        logger.info("Extra password_providers: %r", self.password_providers)
+        logger.info("Extra password_providers: %s", self.password_providers)
 
         self.hs = hs  # FIXME better possibility to access registrationHandler later?
         self.macaroon_gen = hs.get_macaroon_generator()
@@ -184,15 +202,23 @@ class AuthHandler(BaseHandler):
         # type in the list. (NB that the spec doesn't require us to do so and
         # clients which favour types that they don't understand over those that
         # they do are technically broken)
+
+        # start out by assuming PASSWORD is enabled; we will remove it later if not.
         login_types = []
-        if self._password_enabled:
+        if hs.config.password_localdb_enabled:
             login_types.append(LoginType.PASSWORD)
+
         for provider in self.password_providers:
             if hasattr(provider, "get_supported_login_types"):
                 for t in provider.get_supported_login_types().keys():
                     if t not in login_types:
                         login_types.append(t)
+
+        if not self._password_enabled:
+            login_types.remove(LoginType.PASSWORD)
+
         self._supported_login_types = login_types
+
         # Login types and UI Auth types have a heavy overlap, but are not
         # necessarily identical. Login types have SSO (and other login types)
         # added in the rest layer, see synapse.rest.client.v1.login.LoginRestServerlet.on_GET.
@@ -209,10 +235,17 @@ class AuthHandler(BaseHandler):
             burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
         )
 
+        # Ratelimitier for failed /login attempts
+        self._failed_login_attempts_ratelimiter = Ratelimiter(
+            clock=hs.get_clock(),
+            rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
+            burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
+        )
+
         self._clock = self.hs.get_clock()
 
         # Expire old UI auth sessions after a period of time.
-        if hs.config.worker_app is None:
+        if hs.config.run_background_tasks:
             self._clock.looping_call(
                 run_as_background_process,
                 5 * 60 * 1000,
@@ -463,9 +496,7 @@ class AuthHandler(BaseHandler):
             # authentication flow.
             await self.store.set_ui_auth_clientdict(sid, clientdict)
 
-        user_agent = request.requestHeaders.getRawHeaders(b"User-Agent", default=[b""])[
-            0
-        ].decode("ascii", "surrogateescape")
+        user_agent = request.get_user_agent("")
 
         await self.store.add_user_agent_ip_to_ui_auth_session(
             session.session_id, user_agent, clientip
@@ -623,14 +654,8 @@ class AuthHandler(BaseHandler):
             res = await checker.check_auth(authdict, clientip=clientip)
             return res
 
-        # build a v1-login-style dict out of the authdict and fall back to the
-        # v1 code
-        user_id = authdict.get("user")
-
-        if user_id is None:
-            raise SynapseError(400, "", Codes.MISSING_PARAM)
-
-        (canonical_id, callback) = await self.validate_login(user_id, authdict)
+        # fall back to the v1 login flow
+        canonical_id, _ = await self.validate_login(authdict)
         return canonical_id
 
     def _get_params_recaptcha(self) -> dict:
@@ -679,13 +704,17 @@ class AuthHandler(BaseHandler):
         }
 
     async def get_access_token_for_user_id(
-        self, user_id: str, device_id: Optional[str], valid_until_ms: Optional[int]
-    ):
+        self,
+        user_id: str,
+        device_id: Optional[str],
+        valid_until_ms: Optional[int],
+        puppets_user_id: Optional[str] = None,
+    ) -> str:
         """
         Creates a new access token for the user with the given user ID.
 
         The user is assumed to have been authenticated by some other
-        machanism (e.g. CAS), and the user_id converted to the canonical case.
+        mechanism (e.g. CAS), and the user_id converted to the canonical case.
 
         The device will be recorded in the table if it is not there already.
 
@@ -706,13 +735,25 @@ class AuthHandler(BaseHandler):
             fmt_expiry = time.strftime(
                 " until %Y-%m-%d %H:%M:%S", time.localtime(valid_until_ms / 1000.0)
             )
-        logger.info("Logging in user %s on device %s%s", user_id, device_id, fmt_expiry)
+
+        if puppets_user_id:
+            logger.info(
+                "Logging in user %s as %s%s", user_id, puppets_user_id, fmt_expiry
+            )
+        else:
+            logger.info(
+                "Logging in user %s on device %s%s", user_id, device_id, fmt_expiry
+            )
 
         await self.auth.check_auth_blocking(user_id)
 
         access_token = self.macaroon_gen.generate_access_token(user_id)
         await self.store.add_access_token_to_user(
-            user_id, access_token, device_id, valid_until_ms
+            user_id=user_id,
+            token=access_token,
+            device_id=device_id,
+            valid_until_ms=valid_until_ms,
+            puppets_user_id=puppets_user_id,
         )
 
         # the device *should* have been registered before we got here; however,
@@ -789,15 +830,157 @@ class AuthHandler(BaseHandler):
         return self._supported_login_types
 
     async def validate_login(
-        self, username: str, login_submission: Dict[str, Any]
+        self, login_submission: Dict[str, Any], ratelimit: bool = False,
     ) -> Tuple[str, Optional[Callable[[Dict[str, str]], None]]]:
         """Authenticates the user for the /login API
 
-        Also used by the user-interactive auth flow to validate
-        m.login.password auth types.
+        Also used by the user-interactive auth flow to validate auth types which don't
+        have an explicit UIA handler, including m.password.auth.
 
         Args:
-            username: username supplied by the user
+            login_submission: the whole of the login submission
+                (including 'type' and other relevant fields)
+            ratelimit: whether to apply the failed_login_attempt ratelimiter
+        Returns:
+            A tuple of the canonical user id, and optional callback
+                to be called once the access token and device id are issued
+        Raises:
+            StoreError if there was a problem accessing the database
+            SynapseError if there was a problem with the request
+            LoginError if there was an authentication problem.
+        """
+        login_type = login_submission.get("type")
+        if not isinstance(login_type, str):
+            raise SynapseError(400, "Bad parameter: type", Codes.INVALID_PARAM)
+
+        # ideally, we wouldn't be checking the identifier unless we know we have a login
+        # method which uses it (https://github.com/matrix-org/synapse/issues/8836)
+        #
+        # But the auth providers' check_auth interface requires a username, so in
+        # practice we can only support login methods which we can map to a username
+        # anyway.
+
+        # special case to check for "password" for the check_password interface
+        # for the auth providers
+        password = login_submission.get("password")
+        if login_type == LoginType.PASSWORD:
+            if not self._password_enabled:
+                raise SynapseError(400, "Password login has been disabled.")
+            if not isinstance(password, str):
+                raise SynapseError(400, "Bad parameter: password", Codes.INVALID_PARAM)
+
+        # map old-school login fields into new-school "identifier" fields.
+        identifier_dict = convert_client_dict_legacy_fields_to_identifier(
+            login_submission
+        )
+
+        # convert phone type identifiers to generic threepids
+        if identifier_dict["type"] == "m.id.phone":
+            identifier_dict = login_id_phone_to_thirdparty(identifier_dict)
+
+        # convert threepid identifiers to user IDs
+        if identifier_dict["type"] == "m.id.thirdparty":
+            address = identifier_dict.get("address")
+            medium = identifier_dict.get("medium")
+
+            if medium is None or address is None:
+                raise SynapseError(400, "Invalid thirdparty identifier")
+
+            # For emails, canonicalise the address.
+            # We store all email addresses canonicalised in the DB.
+            # (See add_threepid in synapse/handlers/auth.py)
+            if medium == "email":
+                try:
+                    address = canonicalise_email(address)
+                except ValueError as e:
+                    raise SynapseError(400, str(e))
+
+            # We also apply account rate limiting using the 3PID as a key, as
+            # otherwise using 3PID bypasses the ratelimiting based on user ID.
+            if ratelimit:
+                self._failed_login_attempts_ratelimiter.ratelimit(
+                    (medium, address), update=False
+                )
+
+            # Check for login providers that support 3pid login types
+            if login_type == LoginType.PASSWORD:
+                # we've already checked that there is a (valid) password field
+                assert isinstance(password, str)
+                (
+                    canonical_user_id,
+                    callback_3pid,
+                ) = await self.check_password_provider_3pid(medium, address, password)
+                if canonical_user_id:
+                    # Authentication through password provider and 3pid succeeded
+                    return canonical_user_id, callback_3pid
+
+            # No password providers were able to handle this 3pid
+            # Check local store
+            user_id = await self.hs.get_datastore().get_user_id_by_threepid(
+                medium, address
+            )
+            if not user_id:
+                logger.warning(
+                    "unknown 3pid identifier medium %s, address %r", medium, address
+                )
+                # We mark that we've failed to log in here, as
+                # `check_password_provider_3pid` might have returned `None` due
+                # to an incorrect password, rather than the account not
+                # existing.
+                #
+                # If it returned None but the 3PID was bound then we won't hit
+                # this code path, which is fine as then the per-user ratelimit
+                # will kick in below.
+                if ratelimit:
+                    self._failed_login_attempts_ratelimiter.can_do_action(
+                        (medium, address)
+                    )
+                raise LoginError(403, "", errcode=Codes.FORBIDDEN)
+
+            identifier_dict = {"type": "m.id.user", "user": user_id}
+
+        # by this point, the identifier should be an m.id.user: if it's anything
+        # else, we haven't understood it.
+        if identifier_dict["type"] != "m.id.user":
+            raise SynapseError(400, "Unknown login identifier type")
+
+        username = identifier_dict.get("user")
+        if not username:
+            raise SynapseError(400, "User identifier is missing 'user' key")
+
+        if username.startswith("@"):
+            qualified_user_id = username
+        else:
+            qualified_user_id = UserID(username, self.hs.hostname).to_string()
+
+        # Check if we've hit the failed ratelimit (but don't update it)
+        if ratelimit:
+            self._failed_login_attempts_ratelimiter.ratelimit(
+                qualified_user_id.lower(), update=False
+            )
+
+        try:
+            return await self._validate_userid_login(username, login_submission)
+        except LoginError:
+            # The user has failed to log in, so we need to update the rate
+            # limiter. Using `can_do_action` avoids us raising a ratelimit
+            # exception and masking the LoginError. The actual ratelimiting
+            # should have happened above.
+            if ratelimit:
+                self._failed_login_attempts_ratelimiter.can_do_action(
+                    qualified_user_id.lower()
+                )
+            raise
+
+    async def _validate_userid_login(
+        self, username: str, login_submission: Dict[str, Any],
+    ) -> Tuple[str, Optional[Callable[[Dict[str, str]], None]]]:
+        """Helper for validate_login
+
+        Handles login, once we've mapped 3pids onto userids
+
+        Args:
+            username: the username, from the identifier dict
             login_submission: the whole of the login submission
                 (including 'type' and other relevant fields)
         Returns:
@@ -808,38 +991,18 @@ class AuthHandler(BaseHandler):
             SynapseError if there was a problem with the request
             LoginError if there was an authentication problem.
         """
-
         if username.startswith("@"):
             qualified_user_id = username
         else:
             qualified_user_id = UserID(username, self.hs.hostname).to_string()
 
         login_type = login_submission.get("type")
+        # we already checked that we have a valid login type
+        assert isinstance(login_type, str)
+
         known_login_type = False
 
-        # special case to check for "password" for the check_password interface
-        # for the auth providers
-        password = login_submission.get("password")
-
-        if login_type == LoginType.PASSWORD:
-            if not self._password_enabled:
-                raise SynapseError(400, "Password login has been disabled.")
-            if not password:
-                raise SynapseError(400, "Missing parameter: password")
-
         for provider in self.password_providers:
-            if hasattr(provider, "check_password") and login_type == LoginType.PASSWORD:
-                known_login_type = True
-                is_valid = await provider.check_password(qualified_user_id, password)
-                if is_valid:
-                    return qualified_user_id, None
-
-            if not hasattr(provider, "get_supported_login_types") or not hasattr(
-                provider, "check_auth"
-            ):
-                # this password provider doesn't understand custom login types
-                continue
-
             supported_login_types = provider.get_supported_login_types()
             if login_type not in supported_login_types:
                 # this password provider doesn't understand this login type
@@ -864,15 +1027,17 @@ class AuthHandler(BaseHandler):
 
             result = await provider.check_auth(username, login_type, login_dict)
             if result:
-                if isinstance(result, str):
-                    result = (result, None)
                 return result
 
         if login_type == LoginType.PASSWORD and self.hs.config.password_localdb_enabled:
             known_login_type = True
 
+            # we've already checked that there is a (valid) password field
+            password = login_submission["password"]
+            assert isinstance(password, str)
+
             canonical_user_id = await self._check_local_password(
-                qualified_user_id, password  # type: ignore
+                qualified_user_id, password
             )
 
             if canonical_user_id:
@@ -903,19 +1068,9 @@ class AuthHandler(BaseHandler):
             unsuccessful, `user_id` and `callback` are both `None`.
         """
         for provider in self.password_providers:
-            if hasattr(provider, "check_3pid_auth"):
-                # This function is able to return a deferred that either
-                # resolves None, meaning authentication failure, or upon
-                # success, to a str (which is the user_id) or a tuple of
-                # (user_id, callback_func), where callback_func should be run
-                # after we've finished everything else
-                result = await provider.check_3pid_auth(medium, address, password)
-                if result:
-                    # Check if the return value is a str or a tuple
-                    if isinstance(result, str):
-                        # If it's a str, set callback function to None
-                        result = (result, None)
-                    return result
+            result = await provider.check_3pid_auth(medium, address, password)
+            if result:
+                return result
 
         return None, None
 
@@ -973,21 +1128,16 @@ class AuthHandler(BaseHandler):
 
         # see if any of our auth providers want to know about this
         for provider in self.password_providers:
-            if hasattr(provider, "on_logged_out"):
-                # This might return an awaitable, if it does block the log out
-                # until it completes.
-                result = provider.on_logged_out(
-                    user_id=str(user_info["user"]),
-                    device_id=user_info["device_id"],
-                    access_token=access_token,
-                )
-                if inspect.isawaitable(result):
-                    await result
+            await provider.on_logged_out(
+                user_id=user_info.user_id,
+                device_id=user_info.device_id,
+                access_token=access_token,
+            )
 
         # delete pushers associated with this access token
-        if user_info["token_id"] is not None:
+        if user_info.token_id is not None:
             await self.hs.get_pusherpool().remove_pushers_by_access_token(
-                str(user_info["user"]), (user_info["token_id"],)
+                user_info.user_id, (user_info.token_id,)
             )
 
     async def delete_access_tokens_for_user(
@@ -1011,11 +1161,10 @@ class AuthHandler(BaseHandler):
 
         # see if any of our auth providers want to know about this
         for provider in self.password_providers:
-            if hasattr(provider, "on_logged_out"):
-                for token, token_id, device_id in tokens_and_devices:
-                    await provider.on_logged_out(
-                        user_id=user_id, device_id=device_id, access_token=token
-                    )
+            for token, token_id, device_id in tokens_and_devices:
+                await provider.on_logged_out(
+                    user_id=user_id, device_id=device_id, access_token=token
+                )
 
         # delete pushers associated with the access tokens
         await self.hs.get_pusherpool().remove_pushers_by_access_token(
@@ -1073,7 +1222,7 @@ class AuthHandler(BaseHandler):
         if medium == "email":
             address = canonicalise_email(address)
 
-        identity_handler = self.hs.get_handlers().identity_handler
+        identity_handler = self.hs.get_identity_handler()
         result = await identity_handler.try_unbind_threepid(
             user_id, {"medium": medium, "address": address, "id_server": id_server}
         )
@@ -1339,3 +1488,127 @@ class MacaroonGenerator:
         macaroon.add_first_party_caveat("gen = 1")
         macaroon.add_first_party_caveat("user_id = %s" % (user_id,))
         return macaroon
+
+
+class PasswordProvider:
+    """Wrapper for a password auth provider module
+
+    This class abstracts out all of the backwards-compatibility hacks for
+    password providers, to provide a consistent interface.
+    """
+
+    @classmethod
+    def load(cls, module, config, module_api: ModuleApi) -> "PasswordProvider":
+        try:
+            pp = module(config=config, account_handler=module_api)
+        except Exception as e:
+            logger.error("Error while initializing %r: %s", module, e)
+            raise
+        return cls(pp, module_api)
+
+    def __init__(self, pp, module_api: ModuleApi):
+        self._pp = pp
+        self._module_api = module_api
+
+        self._supported_login_types = {}
+
+        # grandfather in check_password support
+        if hasattr(self._pp, "check_password"):
+            self._supported_login_types[LoginType.PASSWORD] = ("password",)
+
+        g = getattr(self._pp, "get_supported_login_types", None)
+        if g:
+            self._supported_login_types.update(g())
+
+    def __str__(self):
+        return str(self._pp)
+
+    def get_supported_login_types(self) -> Mapping[str, Iterable[str]]:
+        """Get the login types supported by this password provider
+
+        Returns a map from a login type identifier (such as m.login.password) to an
+        iterable giving the fields which must be provided by the user in the submission
+        to the /login API.
+
+        This wrapper adds m.login.password to the list if the underlying password
+        provider supports the check_password() api.
+        """
+        return self._supported_login_types
+
+    async def check_auth(
+        self, username: str, login_type: str, login_dict: JsonDict
+    ) -> Optional[Tuple[str, Optional[Callable]]]:
+        """Check if the user has presented valid login credentials
+
+        This wrapper also calls check_password() if the underlying password provider
+        supports the check_password() api and the login type is m.login.password.
+
+        Args:
+            username: user id presented by the client. Either an MXID or an unqualified
+                username.
+
+            login_type: the login type being attempted - one of the types returned by
+                get_supported_login_types()
+
+            login_dict: the dictionary of login secrets passed by the client.
+
+        Returns: (user_id, callback) where `user_id` is the fully-qualified mxid of the
+            user, and `callback` is an optional callback which will be called with the
+            result from the /login call (including access_token, device_id, etc.)
+        """
+        # first grandfather in a call to check_password
+        if login_type == LoginType.PASSWORD:
+            g = getattr(self._pp, "check_password", None)
+            if g:
+                qualified_user_id = self._module_api.get_qualified_user_id(username)
+                is_valid = await self._pp.check_password(
+                    qualified_user_id, login_dict["password"]
+                )
+                if is_valid:
+                    return qualified_user_id, None
+
+        g = getattr(self._pp, "check_auth", None)
+        if not g:
+            return None
+        result = await g(username, login_type, login_dict)
+
+        # Check if the return value is a str or a tuple
+        if isinstance(result, str):
+            # If it's a str, set callback function to None
+            return result, None
+
+        return result
+
+    async def check_3pid_auth(
+        self, medium: str, address: str, password: str
+    ) -> Optional[Tuple[str, Optional[Callable]]]:
+        g = getattr(self._pp, "check_3pid_auth", None)
+        if not g:
+            return None
+
+        # This function is able to return a deferred that either
+        # resolves None, meaning authentication failure, or upon
+        # success, to a str (which is the user_id) or a tuple of
+        # (user_id, callback_func), where callback_func should be run
+        # after we've finished everything else
+        result = await g(medium, address, password)
+
+        # Check if the return value is a str or a tuple
+        if isinstance(result, str):
+            # If it's a str, set callback function to None
+            return result, None
+
+        return result
+
+    async def on_logged_out(
+        self, user_id: str, device_id: Optional[str], access_token: str
+    ) -> None:
+        g = getattr(self._pp, "on_logged_out", None)
+        if not g:
+            return
+
+        # This might return an awaitable, if it does block the log out
+        # until it completes.
+        result = g(user_id=user_id, device_id=device_id, access_token=access_token,)
+        if inspect.isawaitable(result):
+            await result
diff --git a/synapse/handlers/cas_handler.py b/synapse/handlers/cas_handler.py
index a4cc4b9a5a..f4ea0a9767 100644
--- a/synapse/handlers/cas_handler.py
+++ b/synapse/handlers/cas_handler.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 import logging
 import urllib
-from typing import Dict, Optional, Tuple
+from typing import TYPE_CHECKING, Dict, Optional, Tuple
 from xml.etree import ElementTree as ET
 
 from twisted.web.client import PartialDownloadError
@@ -23,6 +23,9 @@ from synapse.api.errors import Codes, LoginError
 from synapse.http.site import SynapseRequest
 from synapse.types import UserID, map_username_to_mxid_localpart
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
@@ -31,10 +34,10 @@ class CasHandler:
     Utility class for to handle the response from a CAS SSO service.
 
     Args:
-        hs (synapse.server.HomeServer)
+        hs
     """
 
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         self.hs = hs
         self._hostname = hs.hostname
         self._auth_handler = hs.get_auth_handler()
@@ -200,29 +203,57 @@ class CasHandler:
             args["session"] = session
         username, user_display_name = await self._validate_ticket(ticket, args)
 
-        localpart = map_username_to_mxid_localpart(username)
-        user_id = UserID(localpart, self._hostname).to_string()
-        registered_user_id = await self._auth_handler.check_user_exists(user_id)
+        # Pull out the user-agent and IP from the request.
+        user_agent = request.get_user_agent("")
+        ip_address = self.hs.get_ip_from_request(request)
+
+        # Get the matrix ID from the CAS username.
+        user_id = await self._map_cas_user_to_matrix_user(
+            username, user_display_name, user_agent, ip_address
+        )
 
         if session:
             await self._auth_handler.complete_sso_ui_auth(
-                registered_user_id, session, request,
+                user_id, session, request,
             )
-
         else:
-            if not registered_user_id:
-                # Pull out the user-agent and IP from the request.
-                user_agent = request.requestHeaders.getRawHeaders(
-                    b"User-Agent", default=[b""]
-                )[0].decode("ascii", "surrogateescape")
-                ip_address = self.hs.get_ip_from_request(request)
-
-                registered_user_id = await self._registration_handler.register_user(
-                    localpart=localpart,
-                    default_display_name=user_display_name,
-                    user_agent_ips=(user_agent, ip_address),
-                )
+            # If this not a UI auth request than there must be a redirect URL.
+            assert client_redirect_url
 
             await self._auth_handler.complete_sso_login(
-                registered_user_id, request, client_redirect_url
+                user_id, request, client_redirect_url
             )
+
+    async def _map_cas_user_to_matrix_user(
+        self,
+        remote_user_id: str,
+        display_name: Optional[str],
+        user_agent: str,
+        ip_address: str,
+    ) -> str:
+        """
+        Given a CAS username, retrieve the user ID for it and possibly register the user.
+
+        Args:
+            remote_user_id: The username from the CAS response.
+            display_name: The display name from the CAS response.
+            user_agent: The user agent of the client making the request.
+            ip_address: The IP address of the client making the request.
+
+        Returns:
+             The user ID associated with this response.
+        """
+
+        localpart = map_username_to_mxid_localpart(remote_user_id)
+        user_id = UserID(localpart, self._hostname).to_string()
+        registered_user_id = await self._auth_handler.check_user_exists(user_id)
+
+        # If the user does not exist, register it.
+        if not registered_user_id:
+            registered_user_id = await self._registration_handler.register_user(
+                localpart=localpart,
+                default_display_name=display_name,
+                user_agent_ips=[(user_agent, ip_address)],
+            )
+
+        return registered_user_id
diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index 6d6af02701..366787ca33 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import Optional
+from typing import TYPE_CHECKING, Optional
 
 from synapse.api.errors import SynapseError
 from synapse.metrics.background_process_metrics import run_as_background_process
@@ -22,28 +22,32 @@ from synapse.types import UserID, create_requester
 
 from ._base import BaseHandler
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
 class DeactivateAccountHandler(BaseHandler):
     """Handler which deals with deactivating user accounts."""
 
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
         self.hs = hs
         self._auth_handler = hs.get_auth_handler()
         self._device_handler = hs.get_device_handler()
         self._room_member_handler = hs.get_room_member_handler()
-        self._identity_handler = hs.get_handlers().identity_handler
+        self._identity_handler = hs.get_identity_handler()
         self._profile_handler = hs.get_profile_handler()
         self.user_directory_handler = hs.get_user_directory_handler()
+        self._server_name = hs.hostname
 
         # Flag that indicates whether the process to part users from rooms is running
         self._user_parter_running = False
 
         # Start the user parter loop so it can resume parting users from rooms where
         # it left off (if it has work left to do).
-        if hs.config.worker_app is None:
+        if hs.config.run_background_tasks:
             hs.get_reactor().callWhenRunning(self._start_user_parting)
 
         self._account_validity_enabled = hs.config.account_validity_enabled
@@ -141,7 +145,7 @@ class DeactivateAccountHandler(BaseHandler):
 
         return identity_server_supports_unbinding
 
-    async def _reject_pending_invites_for_user(self, user_id: str):
+    async def _reject_pending_invites_for_user(self, user_id: str) -> None:
         """Reject pending invites addressed to a given user ID.
 
         Args:
@@ -153,7 +157,7 @@ class DeactivateAccountHandler(BaseHandler):
         for room in pending_invites:
             try:
                 await self._room_member_handler.update_membership(
-                    create_requester(user),
+                    create_requester(user, authenticated_entity=self._server_name),
                     user,
                     room.room_id,
                     "leave",
@@ -209,7 +213,7 @@ class DeactivateAccountHandler(BaseHandler):
             logger.info("User parter parting %r from %r", user_id, room_id)
             try:
                 await self._room_member_handler.update_membership(
-                    create_requester(user),
+                    create_requester(user, authenticated_entity=self._server_name),
                     user,
                     room_id,
                     "leave",
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index b9d9098104..debb1b4f29 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2016 OpenMarket Ltd
 # Copyright 2019 New Vector Ltd
-# Copyright 2019 The Matrix.org Foundation C.I.C.
+# Copyright 2019,2020 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,7 +15,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import Any, Dict, List, Optional
+from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Optional, Set, Tuple
 
 from synapse.api import errors
 from synapse.api.constants import EventTypes
@@ -29,7 +29,10 @@ from synapse.api.errors import (
 from synapse.logging.opentracing import log_kv, set_tag, trace
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.types import (
+    Collection,
+    JsonDict,
     StreamToken,
+    UserID,
     get_domain_from_id,
     get_verify_key_from_cross_signing_key,
 )
@@ -41,13 +44,16 @@ from synapse.util.retryutils import NotRetryingDestination
 
 from ._base import BaseHandler
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 MAX_DEVICE_DISPLAY_NAME_LEN = 100
 
 
 class DeviceWorkerHandler(BaseHandler):
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
 
         self.hs = hs
@@ -105,7 +111,9 @@ class DeviceWorkerHandler(BaseHandler):
 
     @trace
     @measure_func("device.get_user_ids_changed")
-    async def get_user_ids_changed(self, user_id: str, from_token: StreamToken):
+    async def get_user_ids_changed(
+        self, user_id: str, from_token: StreamToken
+    ) -> JsonDict:
         """Get list of users that have had the devices updated, or have newly
         joined a room, that `user_id` may be interested in.
         """
@@ -221,8 +229,8 @@ class DeviceWorkerHandler(BaseHandler):
             possibly_joined = possibly_changed & users_who_share_room
             possibly_left = (possibly_changed | possibly_left) - users_who_share_room
         else:
-            possibly_joined = []
-            possibly_left = []
+            possibly_joined = set()
+            possibly_left = set()
 
         result = {"changed": list(possibly_joined), "left": list(possibly_left)}
 
@@ -230,7 +238,7 @@ class DeviceWorkerHandler(BaseHandler):
 
         return result
 
-    async def on_federation_query_user_devices(self, user_id):
+    async def on_federation_query_user_devices(self, user_id: str) -> JsonDict:
         stream_id, devices = await self.store.get_e2e_device_keys_for_federation_query(
             user_id
         )
@@ -249,7 +257,7 @@ class DeviceWorkerHandler(BaseHandler):
 
 
 class DeviceHandler(DeviceWorkerHandler):
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
 
         self.federation_sender = hs.get_federation_sender()
@@ -264,7 +272,7 @@ class DeviceHandler(DeviceWorkerHandler):
 
         hs.get_distributor().observe("user_left_room", self.user_left_room)
 
-    def _check_device_name_length(self, name: str):
+    def _check_device_name_length(self, name: Optional[str]):
         """
         Checks whether a device name is longer than the maximum allowed length.
 
@@ -283,8 +291,11 @@ class DeviceHandler(DeviceWorkerHandler):
             )
 
     async def check_device_registered(
-        self, user_id, device_id, initial_device_display_name=None
-    ):
+        self,
+        user_id: str,
+        device_id: Optional[str],
+        initial_device_display_name: Optional[str] = None,
+    ) -> str:
         """
         If the given device has not been registered, register it with the
         supplied display name.
@@ -292,12 +303,11 @@ class DeviceHandler(DeviceWorkerHandler):
         If no device_id is supplied, we make one up.
 
         Args:
-            user_id (str):  @user:id
-            device_id (str | None): device id supplied by client
-            initial_device_display_name (str | None): device display name from
-                 client
+            user_id:  @user:id
+            device_id: device id supplied by client
+            initial_device_display_name: device display name from client
         Returns:
-            str: device id (generated if none was supplied)
+            device id (generated if none was supplied)
         """
 
         self._check_device_name_length(initial_device_display_name)
@@ -316,15 +326,15 @@ class DeviceHandler(DeviceWorkerHandler):
         # times in case of a clash.
         attempts = 0
         while attempts < 5:
-            device_id = stringutils.random_string(10).upper()
+            new_device_id = stringutils.random_string(10).upper()
             new_device = await self.store.store_device(
                 user_id=user_id,
-                device_id=device_id,
+                device_id=new_device_id,
                 initial_device_display_name=initial_device_display_name,
             )
             if new_device:
-                await self.notify_device_update(user_id, [device_id])
-                return device_id
+                await self.notify_device_update(user_id, [new_device_id])
+                return new_device_id
             attempts += 1
 
         raise errors.StoreError(500, "Couldn't generate a device ID.")
@@ -433,7 +443,9 @@ class DeviceHandler(DeviceWorkerHandler):
 
     @trace
     @measure_func("notify_device_update")
-    async def notify_device_update(self, user_id, device_ids):
+    async def notify_device_update(
+        self, user_id: str, device_ids: Collection[str]
+    ) -> None:
         """Notify that a user's device(s) has changed. Pokes the notifier, and
         remote servers if the user is local.
         """
@@ -445,7 +457,7 @@ class DeviceHandler(DeviceWorkerHandler):
             user_id
         )
 
-        hosts = set()
+        hosts = set()  # type: Set[str]
         if self.hs.is_mine_id(user_id):
             hosts.update(get_domain_from_id(u) for u in users_who_share_room)
             hosts.discard(self.server_name)
@@ -497,7 +509,7 @@ class DeviceHandler(DeviceWorkerHandler):
 
         self.notifier.on_new_event("device_list_key", position, users=[from_user_id])
 
-    async def user_left_room(self, user, room_id):
+    async def user_left_room(self, user: UserID, room_id: str) -> None:
         user_id = user.to_string()
         room_ids = await self.store.get_rooms_for_user(user_id)
         if not room_ids:
@@ -505,8 +517,89 @@ class DeviceHandler(DeviceWorkerHandler):
             # receive device updates. Mark this in DB.
             await self.store.mark_remote_user_device_list_as_unsubscribed(user_id)
 
+    async def store_dehydrated_device(
+        self,
+        user_id: str,
+        device_data: JsonDict,
+        initial_device_display_name: Optional[str] = None,
+    ) -> str:
+        """Store a dehydrated device for a user.  If the user had a previous
+        dehydrated device, it is removed.
 
-def _update_device_from_client_ips(device, client_ips):
+        Args:
+            user_id: the user that we are storing the device for
+            device_data: the dehydrated device information
+            initial_device_display_name: The display name to use for the device
+        Returns:
+            device id of the dehydrated device
+        """
+        device_id = await self.check_device_registered(
+            user_id, None, initial_device_display_name,
+        )
+        old_device_id = await self.store.store_dehydrated_device(
+            user_id, device_id, device_data
+        )
+        if old_device_id is not None:
+            await self.delete_device(user_id, old_device_id)
+        return device_id
+
+    async def get_dehydrated_device(
+        self, user_id: str
+    ) -> Optional[Tuple[str, JsonDict]]:
+        """Retrieve the information for a dehydrated device.
+
+        Args:
+            user_id: the user whose dehydrated device we are looking for
+        Returns:
+            a tuple whose first item is the device ID, and the second item is
+            the dehydrated device information
+        """
+        return await self.store.get_dehydrated_device(user_id)
+
+    async def rehydrate_device(
+        self, user_id: str, access_token: str, device_id: str
+    ) -> dict:
+        """Process a rehydration request from the user.
+
+        Args:
+            user_id: the user who is rehydrating the device
+            access_token: the access token used for the request
+            device_id: the ID of the device that will be rehydrated
+        Returns:
+            a dict containing {"success": True}
+        """
+        success = await self.store.remove_dehydrated_device(user_id, device_id)
+
+        if not success:
+            raise errors.NotFoundError()
+
+        # If the dehydrated device was successfully deleted (the device ID
+        # matched the stored dehydrated device), then modify the access
+        # token to use the dehydrated device's ID and copy the old device
+        # display name to the dehydrated device, and destroy the old device
+        # ID
+        old_device_id = await self.store.set_device_for_access_token(
+            access_token, device_id
+        )
+        old_device = await self.store.get_device(user_id, old_device_id)
+        await self.store.update_device(user_id, device_id, old_device["display_name"])
+        # can't call self.delete_device because that will clobber the
+        # access token so call the storage layer directly
+        await self.store.delete_device(user_id, old_device_id)
+        await self.store.delete_e2e_keys_by_device(
+            user_id=user_id, device_id=old_device_id
+        )
+
+        # tell everyone that the old device is gone and that the dehydrated
+        # device has a new display name
+        await self.notify_device_update(user_id, [old_device_id, device_id])
+
+        return {"success": True}
+
+
+def _update_device_from_client_ips(
+    device: Dict[str, Any], client_ips: Dict[Tuple[str, str], Dict[str, Any]]
+) -> None:
     ip = client_ips.get((device["user_id"], device["device_id"]), {})
     device.update({"last_seen_ts": ip.get("last_seen"), "last_seen_ip": ip.get("ip")})
 
@@ -514,7 +607,7 @@ def _update_device_from_client_ips(device, client_ips):
 class DeviceListUpdater:
     "Handles incoming device list updates from federation and updates the DB"
 
-    def __init__(self, hs, device_handler):
+    def __init__(self, hs: "HomeServer", device_handler: DeviceHandler):
         self.store = hs.get_datastore()
         self.federation = hs.get_federation_client()
         self.clock = hs.get_clock()
@@ -523,7 +616,9 @@ class DeviceListUpdater:
         self._remote_edu_linearizer = Linearizer(name="remote_device_list")
 
         # user_id -> list of updates waiting to be handled.
-        self._pending_updates = {}
+        self._pending_updates = (
+            {}
+        )  # type: Dict[str, List[Tuple[str, str, Iterable[str], JsonDict]]]
 
         # Recently seen stream ids. We don't bother keeping these in the DB,
         # but they're useful to have them about to reduce the number of spurious
@@ -546,7 +641,9 @@ class DeviceListUpdater:
         )
 
     @trace
-    async def incoming_device_list_update(self, origin, edu_content):
+    async def incoming_device_list_update(
+        self, origin: str, edu_content: JsonDict
+    ) -> None:
         """Called on incoming device list update from federation. Responsible
         for parsing the EDU and adding to pending updates list.
         """
@@ -607,7 +704,7 @@ class DeviceListUpdater:
         await self._handle_device_updates(user_id)
 
     @measure_func("_incoming_device_list_update")
-    async def _handle_device_updates(self, user_id):
+    async def _handle_device_updates(self, user_id: str) -> None:
         "Actually handle pending updates."
 
         with (await self._remote_edu_linearizer.queue(user_id)):
@@ -655,7 +752,9 @@ class DeviceListUpdater:
                     stream_id for _, stream_id, _, _ in pending_updates
                 )
 
-    async def _need_to_do_resync(self, user_id, updates):
+    async def _need_to_do_resync(
+        self, user_id: str, updates: Iterable[Tuple[str, str, Iterable[str], JsonDict]]
+    ) -> bool:
         """Given a list of updates for a user figure out if we need to do a full
         resync, or whether we have enough data that we can just apply the delta.
         """
@@ -686,7 +785,7 @@ class DeviceListUpdater:
         return False
 
     @trace
-    async def _maybe_retry_device_resync(self):
+    async def _maybe_retry_device_resync(self) -> None:
         """Retry to resync device lists that are out of sync, except if another retry is
         in progress.
         """
@@ -729,7 +828,7 @@ class DeviceListUpdater:
 
     async def user_device_resync(
         self, user_id: str, mark_failed_as_stale: bool = True
-    ) -> Optional[dict]:
+    ) -> Optional[JsonDict]:
         """Fetches all devices for a user and updates the device cache with them.
 
         Args:
@@ -753,7 +852,7 @@ class DeviceListUpdater:
                 # it later.
                 await self.store.mark_remote_user_device_cache_as_stale(user_id)
 
-            return
+            return None
         except (RequestSendFailed, HttpResponseException) as e:
             logger.warning(
                 "Failed to handle device list update for %s: %s", user_id, e,
@@ -770,12 +869,12 @@ class DeviceListUpdater:
             # next time we get a device list update for this user_id.
             # This makes it more likely that the device lists will
             # eventually become consistent.
-            return
+            return None
         except FederationDeniedError as e:
             set_tag("error", True)
             log_kv({"reason": "FederationDeniedError"})
             logger.info(e)
-            return
+            return None
         except Exception as e:
             set_tag("error", True)
             log_kv(
@@ -788,7 +887,7 @@ class DeviceListUpdater:
                 # it later.
                 await self.store.mark_remote_user_device_cache_as_stale(user_id)
 
-            return
+            return None
         log_kv({"result": result})
         stream_id = result["stream_id"]
         devices = result["devices"]
@@ -849,7 +948,7 @@ class DeviceListUpdater:
         user_id: str,
         master_key: Optional[Dict[str, Any]],
         self_signing_key: Optional[Dict[str, Any]],
-    ) -> list:
+    ) -> List[str]:
         """Process the given new master and self-signing key for the given remote user.
 
         Args:
diff --git a/synapse/handlers/devicemessage.py b/synapse/handlers/devicemessage.py
index 64ef7f63ab..9cac5a8463 100644
--- a/synapse/handlers/devicemessage.py
+++ b/synapse/handlers/devicemessage.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 import logging
-from typing import Any, Dict
+from typing import TYPE_CHECKING, Any, Dict
 
 from synapse.api.errors import SynapseError
 from synapse.logging.context import run_in_background
@@ -24,18 +24,22 @@ from synapse.logging.opentracing import (
     set_tag,
     start_active_span,
 )
-from synapse.types import UserID, get_domain_from_id
+from synapse.types import JsonDict, UserID, get_domain_from_id
 from synapse.util import json_encoder
 from synapse.util.stringutils import random_string
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
+
 logger = logging.getLogger(__name__)
 
 
 class DeviceMessageHandler:
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         """
         Args:
-            hs (synapse.server.HomeServer): server
+            hs: server
         """
         self.store = hs.get_datastore()
         self.notifier = hs.get_notifier()
@@ -48,7 +52,7 @@ class DeviceMessageHandler:
 
         self._device_list_updater = hs.get_device_handler().device_list_updater
 
-    async def on_direct_to_device_edu(self, origin, content):
+    async def on_direct_to_device_edu(self, origin: str, content: JsonDict) -> None:
         local_messages = {}
         sender_user_id = content["sender"]
         if origin != get_domain_from_id(sender_user_id):
@@ -95,7 +99,7 @@ class DeviceMessageHandler:
         message_type: str,
         sender_user_id: str,
         by_device: Dict[str, Dict[str, Any]],
-    ):
+    ) -> None:
         """Checks inbound device messages for unknown remote devices, and if
         found marks the remote cache for the user as stale.
         """
@@ -138,11 +142,16 @@ class DeviceMessageHandler:
                 self._device_list_updater.user_device_resync, sender_user_id
             )
 
-    async def send_device_message(self, sender_user_id, message_type, messages):
+    async def send_device_message(
+        self,
+        sender_user_id: str,
+        message_type: str,
+        messages: Dict[str, Dict[str, JsonDict]],
+    ) -> None:
         set_tag("number_of_messages", len(messages))
         set_tag("sender", sender_user_id)
         local_messages = {}
-        remote_messages = {}
+        remote_messages = {}  # type: Dict[str, Dict[str, Dict[str, JsonDict]]]
         for user_id, by_device in messages.items():
             # we use UserID.from_string to catch invalid user ids
             if self.is_mine(UserID.from_string(user_id)):
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 654e76f2c9..ad5683d251 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -384,7 +384,7 @@ class DirectoryHandler(BaseHandler):
         """
         creator = await self.store.get_room_alias_creator(alias.to_string())
 
-        if creator is not None and creator == user_id:
+        if creator == user_id:
             return True
 
         # Resolve the alias to the corresponding room.
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index dd40fd1299..929752150d 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -129,6 +129,11 @@ class E2eKeysHandler:
                 if user_id in local_query:
                     results[user_id] = keys
 
+        # Get cached cross-signing keys
+        cross_signing_keys = await self.get_cross_signing_keys_from_cache(
+            device_keys_query, from_user_id
+        )
+
         # Now attempt to get any remote devices from our local cache.
         remote_queries_not_in_cache = {}
         if remote_queries:
@@ -155,16 +160,28 @@ class E2eKeysHandler:
                             unsigned["device_display_name"] = device_display_name
                         user_devices[device_id] = result
 
+            # check for missing cross-signing keys.
+            for user_id in remote_queries.keys():
+                cached_cross_master = user_id in cross_signing_keys["master_keys"]
+                cached_cross_selfsigning = (
+                    user_id in cross_signing_keys["self_signing_keys"]
+                )
+
+                # check if we are missing only one of cross-signing master or
+                # self-signing key, but the other one is cached.
+                # as we need both, this will issue a federation request.
+                # if we don't have any of the keys, either the user doesn't have
+                # cross-signing set up, or the cached device list
+                # is not (yet) updated.
+                if cached_cross_master ^ cached_cross_selfsigning:
+                    user_ids_not_in_cache.add(user_id)
+
+            # add those users to the list to fetch over federation.
             for user_id in user_ids_not_in_cache:
                 domain = get_domain_from_id(user_id)
                 r = remote_queries_not_in_cache.setdefault(domain, {})
                 r[user_id] = remote_queries[user_id]
 
-        # Get cached cross-signing keys
-        cross_signing_keys = await self.get_cross_signing_keys_from_cache(
-            device_keys_query, from_user_id
-        )
-
         # Now fetch any devices that we don't have in our cache
         @trace
         async def do_remote_query(destination):
@@ -496,6 +513,22 @@ class E2eKeysHandler:
             log_kv(
                 {"message": "Did not update one_time_keys", "reason": "no keys given"}
             )
+        fallback_keys = keys.get("org.matrix.msc2732.fallback_keys", None)
+        if fallback_keys and isinstance(fallback_keys, dict):
+            log_kv(
+                {
+                    "message": "Updating fallback_keys for device.",
+                    "user_id": user_id,
+                    "device_id": device_id,
+                }
+            )
+            await self.store.set_e2e_fallback_keys(user_id, device_id, fallback_keys)
+        elif fallback_keys:
+            log_kv({"message": "Did not update fallback_keys", "reason": "not a dict"})
+        else:
+            log_kv(
+                {"message": "Did not update fallback_keys", "reason": "no keys given"}
+            )
 
         # the device should have been registered already, but it may have been
         # deleted due to a race with a DELETE request. Or we may be using an
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 29ec18e25e..f27dd84213 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -55,6 +55,7 @@ from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
 from synapse.events.validator import EventValidator
 from synapse.handlers._base import BaseHandler
+from synapse.http.servlet import assert_params_in_dict
 from synapse.logging.context import (
     make_deferred_yieldable,
     nested_logging_context,
@@ -67,7 +68,7 @@ from synapse.replication.http.devices import ReplicationUserDevicesResyncRestSer
 from synapse.replication.http.federation import (
     ReplicationCleanRoomRestServlet,
     ReplicationFederationSendEventsRestServlet,
-    ReplicationStoreRoomOnInviteRestServlet,
+    ReplicationStoreRoomOnOutlierMembershipRestServlet,
 )
 from synapse.state import StateResolutionStore
 from synapse.storage.databases.main.events_worker import EventRedactBehaviour
@@ -112,7 +113,7 @@ class FederationHandler(BaseHandler):
     """Handles events that originated from federation.
         Responsible for:
         a) handling received Pdus before handing them on as Events to the rest
-        of the homeserver (including auth and state conflict resoultion)
+        of the homeserver (including auth and state conflict resolutions)
         b) converting events that were produced by local clients that may need
         to be sent to remote homeservers.
         c) doing the necessary dances to invite remote users and join remote
@@ -152,12 +153,14 @@ class FederationHandler(BaseHandler):
             self._user_device_resync = ReplicationUserDevicesResyncRestServlet.make_client(
                 hs
             )
-            self._maybe_store_room_on_invite = ReplicationStoreRoomOnInviteRestServlet.make_client(
+            self._maybe_store_room_on_outlier_membership = ReplicationStoreRoomOnOutlierMembershipRestServlet.make_client(
                 hs
             )
         else:
             self._device_list_updater = hs.get_device_handler().device_list_updater
-            self._maybe_store_room_on_invite = self.store.maybe_store_room_on_invite
+            self._maybe_store_room_on_outlier_membership = (
+                self.store.maybe_store_room_on_outlier_membership
+            )
 
         # When joining a room we need to queue any events for that room up.
         # For each room, a list of (pdu, origin) tuples.
@@ -480,7 +483,7 @@ class FederationHandler(BaseHandler):
         # ----
         #
         # Update richvdh 2018/09/18: There are a number of problems with timing this
-        # request out agressively on the client side:
+        # request out aggressively on the client side:
         #
         # - it plays badly with the server-side rate-limiter, which starts tarpitting you
         #   if you send too many requests at once, so you end up with the server carefully
@@ -498,13 +501,13 @@ class FederationHandler(BaseHandler):
         #   we'll end up back here for the *next* PDU in the list, which exacerbates the
         #   problem.
         #
-        # - the agressive 10s timeout was introduced to deal with incoming federation
+        # - the aggressive 10s timeout was introduced to deal with incoming federation
         #   requests taking 8 hours to process. It's not entirely clear why that was going
         #   on; certainly there were other issues causing traffic storms which are now
         #   resolved, and I think in any case we may be more sensible about our locking
         #   now. We're *certainly* more sensible about our logging.
         #
-        # All that said: Let's try increasing the timout to 60s and see what happens.
+        # All that said: Let's try increasing the timeout to 60s and see what happens.
 
         try:
             missing_events = await self.federation_client.get_missing_events(
@@ -1123,7 +1126,7 @@ class FederationHandler(BaseHandler):
                     logger.info(str(e))
                     continue
                 except RequestSendFailed as e:
-                    logger.info("Falied to get backfill from %s because %s", dom, e)
+                    logger.info("Failed to get backfill from %s because %s", dom, e)
                     continue
                 except FederationDeniedError as e:
                     logger.info(e)
@@ -1510,18 +1513,9 @@ class FederationHandler(BaseHandler):
             event, context = await self.event_creation_handler.create_new_client_event(
                 builder=builder
             )
-        except AuthError as e:
+        except SynapseError as e:
             logger.warning("Failed to create join to %s because %s", room_id, e)
-            raise e
-
-        event_allowed = await self.third_party_event_rules.check_event_allowed(
-            event, context
-        )
-        if not event_allowed:
-            logger.info("Creation of join %s forbidden by third-party rules", event)
-            raise SynapseError(
-                403, "This event is not allowed in this context", Codes.FORBIDDEN
-            )
+            raise
 
         # The remote hasn't signed it yet, obviously. We'll do the full checks
         # when we get the event back in `on_send_join_request`
@@ -1557,7 +1551,7 @@ class FederationHandler(BaseHandler):
         #
         # The reasons we have the destination server rather than the origin
         # server send it are slightly mysterious: the origin server should have
-        # all the neccessary state once it gets the response to the send_join,
+        # all the necessary state once it gets the response to the send_join,
         # so it could send the event itself if it wanted to. It may be that
         # doing it this way reduces failure modes, or avoids certain attacks
         # where a new server selectively tells a subset of the federation that
@@ -1570,15 +1564,6 @@ class FederationHandler(BaseHandler):
 
         context = await self._handle_new_event(origin, event)
 
-        event_allowed = await self.third_party_event_rules.check_event_allowed(
-            event, context
-        )
-        if not event_allowed:
-            logger.info("Sending of join %s forbidden by third-party rules", event)
-            raise SynapseError(
-                403, "This event is not allowed in this context", Codes.FORBIDDEN
-            )
-
         logger.debug(
             "on_send_join_request: After _handle_new_event: %s, sigs: %s",
             event.event_id,
@@ -1645,7 +1630,7 @@ class FederationHandler(BaseHandler):
         # keep a record of the room version, if we don't yet know it.
         # (this may get overwritten if we later get a different room version in a
         # join dance).
-        await self._maybe_store_room_on_invite(
+        await self._maybe_store_room_on_outlier_membership(
             room_id=event.room_id, room_version=room_version
         )
 
@@ -1677,7 +1662,7 @@ class FederationHandler(BaseHandler):
         event.internal_metadata.outlier = True
         event.internal_metadata.out_of_band_membership = True
 
-        # Try the host that we succesfully called /make_leave/ on first for
+        # Try the host that we successfully called /make_leave/ on first for
         # the /send_leave/ request.
         host_list = list(target_hosts)
         try:
@@ -1758,15 +1743,6 @@ class FederationHandler(BaseHandler):
             builder=builder
         )
 
-        event_allowed = await self.third_party_event_rules.check_event_allowed(
-            event, context
-        )
-        if not event_allowed:
-            logger.warning("Creation of leave %s forbidden by third-party rules", event)
-            raise SynapseError(
-                403, "This event is not allowed in this context", Codes.FORBIDDEN
-            )
-
         try:
             # The remote hasn't signed it yet, obviously. We'll do the full checks
             # when we get the event back in `on_send_leave_request`
@@ -1799,16 +1775,7 @@ class FederationHandler(BaseHandler):
 
         event.internal_metadata.outlier = False
 
-        context = await self._handle_new_event(origin, event)
-
-        event_allowed = await self.third_party_event_rules.check_event_allowed(
-            event, context
-        )
-        if not event_allowed:
-            logger.info("Sending of leave %s forbidden by third-party rules", event)
-            raise SynapseError(
-                403, "This event is not allowed in this context", Codes.FORBIDDEN
-            )
+        await self._handle_new_event(origin, event)
 
         logger.debug(
             "on_send_leave_request: After _handle_new_event: %s, sigs: %s",
@@ -2704,18 +2671,6 @@ class FederationHandler(BaseHandler):
                 builder=builder
             )
 
-            event_allowed = await self.third_party_event_rules.check_event_allowed(
-                event, context
-            )
-            if not event_allowed:
-                logger.info(
-                    "Creation of threepid invite %s forbidden by third-party rules",
-                    event,
-                )
-                raise SynapseError(
-                    403, "This event is not allowed in this context", Codes.FORBIDDEN
-                )
-
             event, context = await self.add_display_name_to_third_party_invite(
                 room_version, event_dict, event, context
             )
@@ -2744,7 +2699,7 @@ class FederationHandler(BaseHandler):
             )
 
     async def on_exchange_third_party_invite_request(
-        self, room_id: str, event_dict: JsonDict
+        self, event_dict: JsonDict
     ) -> None:
         """Handle an exchange_third_party_invite request from a remote server
 
@@ -2752,12 +2707,11 @@ class FederationHandler(BaseHandler):
         into a normal m.room.member invite.
 
         Args:
-            room_id: The ID of the room.
-
-            event_dict (dict[str, Any]): Dictionary containing the event body.
+            event_dict: Dictionary containing the event body.
 
         """
-        room_version = await self.store.get_room_version_id(room_id)
+        assert_params_in_dict(event_dict, ["room_id"])
+        room_version = await self.store.get_room_version_id(event_dict["room_id"])
 
         # NB: event_dict has a particular specced format we might need to fudge
         # if we change event formats too much.
@@ -2766,18 +2720,6 @@ class FederationHandler(BaseHandler):
         event, context = await self.event_creation_handler.create_new_client_event(
             builder=builder
         )
-
-        event_allowed = await self.third_party_event_rules.check_event_allowed(
-            event, context
-        )
-        if not event_allowed:
-            logger.warning(
-                "Exchange of threepid invite %s forbidden by third-party rules", event
-            )
-            raise SynapseError(
-                403, "This event is not allowed in this context", Codes.FORBIDDEN
-            )
-
         event, context = await self.add_display_name_to_third_party_invite(
             room_version, event_dict, event, context
         )
@@ -2976,17 +2918,20 @@ class FederationHandler(BaseHandler):
             return result["max_stream_id"]
         else:
             assert self.storage.persistence
-            max_stream_token = await self.storage.persistence.persist_events(
+
+            # Note that this returns the events that were persisted, which may not be
+            # the same as were passed in if some were deduplicated due to transaction IDs.
+            events, max_stream_token = await self.storage.persistence.persist_events(
                 event_and_contexts, backfilled=backfilled
             )
 
             if self._ephemeral_messages_enabled:
-                for (event, context) in event_and_contexts:
+                for event in events:
                     # If there's an expiry timestamp on the event, schedule its expiry.
                     self._message_handler.maybe_schedule_expiry(event)
 
             if not backfilled:  # Never notify for backfilled events
-                for event, _ in event_and_contexts:
+                for event in events:
                     await self._notify_persisted_event(event, max_stream_token)
 
             return max_stream_token.stream
@@ -3018,6 +2963,9 @@ class FederationHandler(BaseHandler):
         elif event.internal_metadata.is_outlier():
             return
 
+        # the event has been persisted so it should have a stream ordering.
+        assert event.internal_metadata.stream_ordering
+
         event_pos = PersistedEventPosition(
             self._instance_name, event.internal_metadata.stream_ordering
         )
diff --git a/synapse/handlers/groups_local.py b/synapse/handlers/groups_local.py
index 9684e60fc8..abd8d2af44 100644
--- a/synapse/handlers/groups_local.py
+++ b/synapse/handlers/groups_local.py
@@ -17,7 +17,7 @@
 import logging
 
 from synapse.api.errors import HttpResponseException, RequestSendFailed, SynapseError
-from synapse.types import get_domain_from_id
+from synapse.types import GroupID, get_domain_from_id
 
 logger = logging.getLogger(__name__)
 
@@ -28,6 +28,9 @@ def _create_rerouter(func_name):
     """
 
     async def f(self, group_id, *args, **kwargs):
+        if not GroupID.is_valid(group_id):
+            raise SynapseError(400, "%s was not legal group ID" % (group_id,))
+
         if self.is_mine_id(group_id):
             return await getattr(self.groups_server_handler, func_name)(
                 group_id, *args, **kwargs
@@ -346,7 +349,7 @@ class GroupsLocalHandler(GroupsLocalWorkerHandler):
                 server_name=get_domain_from_id(group_id),
             )
 
-        # TODO: Check that the group is public and we're being added publically
+        # TODO: Check that the group is public and we're being added publicly
         is_publicised = content.get("publicise", False)
 
         token = await self.store.register_user_group_membership(
@@ -391,7 +394,7 @@ class GroupsLocalHandler(GroupsLocalWorkerHandler):
                 server_name=get_domain_from_id(group_id),
             )
 
-        # TODO: Check that the group is public and we're being added publically
+        # TODO: Check that the group is public and we're being added publicly
         is_publicised = content.get("publicise", False)
 
         token = await self.store.register_user_group_membership(
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index c5ff072d5a..b8a6b1d491 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -380,7 +380,8 @@ class IdentityHandler(BaseHandler):
             raise SynapseError(500, "An error was encountered when sending the email")
 
         token_expires = (
-            self.hs.clock.time_msec() + self.hs.config.email_validation_token_lifetime
+            self.hs.get_clock().time_msec()
+            + self.hs.config.email_validation_token_lifetime
         )
 
         await self.store.start_or_continue_validation_session(
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index 39a85801c1..cb11754bf8 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 import logging
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional, Tuple
 
 from twisted.internet import defer
 
@@ -47,12 +47,14 @@ class InitialSyncHandler(BaseHandler):
         self.state = hs.get_state_handler()
         self.clock = hs.get_clock()
         self.validator = EventValidator()
-        self.snapshot_cache = ResponseCache(hs, "initial_sync_cache")
+        self.snapshot_cache = ResponseCache(
+            hs, "initial_sync_cache"
+        )  # type: ResponseCache[Tuple[str, Optional[StreamToken], Optional[StreamToken], str, Optional[int], bool, bool]]
         self._event_serializer = hs.get_event_client_serializer()
         self.storage = hs.get_storage()
         self.state_store = self.storage.state
 
-    def snapshot_all_rooms(
+    async def snapshot_all_rooms(
         self,
         user_id: str,
         pagin_config: PaginationConfig,
@@ -84,7 +86,7 @@ class InitialSyncHandler(BaseHandler):
             include_archived,
         )
 
-        return self.snapshot_cache.wrap(
+        return await self.snapshot_cache.wrap(
             key,
             self._snapshot_all_rooms,
             user_id,
@@ -291,6 +293,10 @@ class InitialSyncHandler(BaseHandler):
                 user_id, room_id, pagin_config, membership, is_peeking
             )
         elif membership == Membership.LEAVE:
+            # The member_event_id will always be available if membership is set
+            # to leave.
+            assert member_event_id
+
             result = await self._room_initial_sync_parted(
                 user_id, room_id, pagin_config, membership, member_event_id, is_peeking
             )
@@ -313,7 +319,7 @@ class InitialSyncHandler(BaseHandler):
         user_id: str,
         room_id: str,
         pagin_config: PaginationConfig,
-        membership: Membership,
+        membership: str,
         member_event_id: str,
         is_peeking: bool,
     ) -> JsonDict:
@@ -365,7 +371,7 @@ class InitialSyncHandler(BaseHandler):
         user_id: str,
         room_id: str,
         pagin_config: PaginationConfig,
-        membership: Membership,
+        membership: str,
         is_peeking: bool,
     ) -> JsonDict:
         current_state = await self.state.get_current_state(room_id=room_id)
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 8949343801..96843338ae 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -50,9 +50,8 @@ from synapse.replication.http.send_event import ReplicationSendEventRestServlet
 from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.storage.state import StateFilter
 from synapse.types import Requester, RoomAlias, StreamToken, UserID, create_requester
-from synapse.util import json_decoder
+from synapse.util import json_decoder, json_encoder
 from synapse.util.async_helpers import Linearizer
-from synapse.util.frozenutils import frozendict_json_encoder
 from synapse.util.metrics import measure_func
 from synapse.visibility import filter_events_for_client
 
@@ -402,21 +401,23 @@ class EventCreationHandler:
             self.config.block_events_without_consent_error
         )
 
-        # Rooms which should be excluded from dummy insertion. (For instance,
-        # those without local users who can send events into the room).
-        #
-        # map from room id to time-of-last-attempt.
-        #
-        self._rooms_to_exclude_from_dummy_event_insertion = {}  # type: Dict[str, int]
-
         # we need to construct a ConsentURIBuilder here, as it checks that the necessary
         # config options, but *only* if we have a configuration for which we are
         # going to need it.
         if self._block_events_without_consent_error:
             self._consent_uri_builder = ConsentURIBuilder(self.config)
 
+        # Rooms which should be excluded from dummy insertion. (For instance,
+        # those without local users who can send events into the room).
+        #
+        # map from room id to time-of-last-attempt.
+        #
+        self._rooms_to_exclude_from_dummy_event_insertion = {}  # type: Dict[str, int]
+        # The number of forward extremeities before a dummy event is sent.
+        self._dummy_events_threshold = hs.config.dummy_events_threshold
+
         if (
-            not self.config.worker_app
+            self.config.run_background_tasks
             and self.config.cleanup_extremities_with_dummy_events
         ):
             self.clock.looping_call(
@@ -431,15 +432,13 @@ class EventCreationHandler:
 
         self._ephemeral_events_enabled = hs.config.enable_ephemeral_messages
 
-        self._dummy_events_threshold = hs.config.dummy_events_threshold
-
     async def create_event(
         self,
         requester: Requester,
         event_dict: dict,
-        token_id: Optional[str] = None,
         txn_id: Optional[str] = None,
         prev_event_ids: Optional[List[str]] = None,
+        auth_event_ids: Optional[List[str]] = None,
         require_consent: bool = True,
     ) -> Tuple[EventBase, EventContext]:
         """
@@ -453,13 +452,18 @@ class EventCreationHandler:
         Args:
             requester
             event_dict: An entire event
-            token_id
             txn_id
             prev_event_ids:
                 the forward extremities to use as the prev_events for the
                 new event.
 
                 If None, they will be requested from the database.
+
+            auth_event_ids:
+                The event ids to use as the auth_events for the new event.
+                Should normally be left as None, which will cause them to be calculated
+                based on the room state at the prev_events.
+
             require_consent: Whether to check if the requester has
                 consented to the privacy policy.
         Raises:
@@ -468,7 +472,7 @@ class EventCreationHandler:
         Returns:
             Tuple of created event, Context
         """
-        await self.auth.check_auth_blocking(requester.user.to_string())
+        await self.auth.check_auth_blocking(requester=requester)
 
         if event_dict["type"] == EventTypes.Create and event_dict["state_key"] == "":
             room_version = event_dict["content"]["room_version"]
@@ -511,14 +515,17 @@ class EventCreationHandler:
         if require_consent and not is_exempt:
             await self.assert_accepted_privacy_policy(requester)
 
-        if token_id is not None:
-            builder.internal_metadata.token_id = token_id
+        if requester.access_token_id is not None:
+            builder.internal_metadata.token_id = requester.access_token_id
 
         if txn_id is not None:
             builder.internal_metadata.txn_id = txn_id
 
         event, context = await self.create_new_client_event(
-            builder=builder, requester=requester, prev_event_ids=prev_event_ids,
+            builder=builder,
+            requester=requester,
+            prev_event_ids=prev_event_ids,
+            auth_event_ids=auth_event_ids,
         )
 
         # In an ideal world we wouldn't need the second part of this condition. However,
@@ -612,7 +619,13 @@ class EventCreationHandler:
         if requester.app_service is not None:
             return
 
-        user_id = requester.user.to_string()
+        user_id = requester.authenticated_entity
+        if not user_id.startswith("@"):
+            # The authenticated entity might not be a user, e.g. if it's the
+            # server puppetting the user.
+            return
+
+        user = UserID.from_string(user_id)
 
         # exempt the system notices user
         if (
@@ -632,65 +645,10 @@ class EventCreationHandler:
         if u["consent_version"] == self.config.user_consent_version:
             return
 
-        consent_uri = self._consent_uri_builder.build_user_consent_uri(
-            requester.user.localpart
-        )
+        consent_uri = self._consent_uri_builder.build_user_consent_uri(user.localpart)
         msg = self._block_events_without_consent_error % {"consent_uri": consent_uri}
         raise ConsentNotGivenError(msg=msg, consent_uri=consent_uri)
 
-    async def send_nonmember_event(
-        self,
-        requester: Requester,
-        event: EventBase,
-        context: EventContext,
-        ratelimit: bool = True,
-        ignore_shadow_ban: bool = False,
-    ) -> int:
-        """
-        Persists and notifies local clients and federation of an event.
-
-        Args:
-            requester: The requester sending the event.
-            event: The event to send.
-            context: The context of the event.
-            ratelimit: Whether to rate limit this send.
-            ignore_shadow_ban: True if shadow-banned users should be allowed to
-                send this event.
-
-        Return:
-            The stream_id of the persisted event.
-
-        Raises:
-            ShadowBanError if the requester has been shadow-banned.
-        """
-        if event.type == EventTypes.Member:
-            raise SynapseError(
-                500, "Tried to send member event through non-member codepath"
-            )
-
-        if not ignore_shadow_ban and requester.shadow_banned:
-            # We randomly sleep a bit just to annoy the requester.
-            await self.clock.sleep(random.randint(1, 10))
-            raise ShadowBanError()
-
-        user = UserID.from_string(event.sender)
-
-        assert self.hs.is_mine(user), "User must be our own: %s" % (user,)
-
-        if event.is_state():
-            prev_event = await self.deduplicate_state_event(event, context)
-            if prev_event is not None:
-                logger.info(
-                    "Not bothering to persist state event %s duplicated by %s",
-                    event.event_id,
-                    prev_event.event_id,
-                )
-                return await self.store.get_stream_id_for_event(prev_event.event_id)
-
-        return await self.handle_new_client_event(
-            requester=requester, event=event, context=context, ratelimit=ratelimit
-        )
-
     async def deduplicate_state_event(
         self, event: EventBase, context: EventContext
     ) -> Optional[EventBase]:
@@ -702,7 +660,7 @@ class EventCreationHandler:
             context: The event context.
 
         Returns:
-            The previous verion of the event is returned, if it is found in the
+            The previous version of the event is returned, if it is found in the
             event context. Otherwise, None is returned.
         """
         prev_state_ids = await context.get_prev_state_ids()
@@ -731,7 +689,7 @@ class EventCreationHandler:
         """
         Creates an event, then sends it.
 
-        See self.create_event and self.send_nonmember_event.
+        See self.create_event and self.handle_new_client_event.
 
         Args:
             requester: The requester sending the event.
@@ -741,9 +699,19 @@ class EventCreationHandler:
             ignore_shadow_ban: True if shadow-banned users should be allowed to
                 send this event.
 
+        Returns:
+            The event, and its stream ordering (if deduplication happened,
+            the previous, duplicate event).
+
         Raises:
             ShadowBanError if the requester has been shadow-banned.
         """
+
+        if event_dict["type"] == EventTypes.Member:
+            raise SynapseError(
+                500, "Tried to send member event through non-member codepath"
+            )
+
         if not ignore_shadow_ban and requester.shadow_banned:
             # We randomly sleep a bit just to annoy the requester.
             await self.clock.sleep(random.randint(1, 10))
@@ -755,8 +723,25 @@ class EventCreationHandler:
         # extremities to pile up, which in turn leads to state resolution
         # taking longer.
         with (await self.limiter.queue(event_dict["room_id"])):
+            if txn_id and requester.access_token_id:
+                existing_event_id = await self.store.get_event_id_from_transaction_id(
+                    event_dict["room_id"],
+                    requester.user.to_string(),
+                    requester.access_token_id,
+                    txn_id,
+                )
+                if existing_event_id:
+                    event = await self.store.get_event(existing_event_id)
+                    # we know it was persisted, so must have a stream ordering
+                    assert event.internal_metadata.stream_ordering
+                    return event, event.internal_metadata.stream_ordering
+
             event, context = await self.create_event(
-                requester, event_dict, token_id=requester.access_token_id, txn_id=txn_id
+                requester, event_dict, txn_id=txn_id
+            )
+
+            assert self.hs.is_mine_id(event.sender), "User must be our own: %s" % (
+                event.sender,
             )
 
             spam_error = self.spam_checker.check_event_for_spam(event)
@@ -765,14 +750,17 @@ class EventCreationHandler:
                     spam_error = "Spam is not permitted here"
                 raise SynapseError(403, spam_error, Codes.FORBIDDEN)
 
-            stream_id = await self.send_nonmember_event(
-                requester,
-                event,
-                context,
+            ev = await self.handle_new_client_event(
+                requester=requester,
+                event=event,
+                context=context,
                 ratelimit=ratelimit,
                 ignore_shadow_ban=ignore_shadow_ban,
             )
-        return event, stream_id
+
+        # we know it was persisted, so must have a stream ordering
+        assert ev.internal_metadata.stream_ordering
+        return ev, ev.internal_metadata.stream_ordering
 
     @measure_func("create_new_client_event")
     async def create_new_client_event(
@@ -780,6 +768,7 @@ class EventCreationHandler:
         builder: EventBuilder,
         requester: Optional[Requester] = None,
         prev_event_ids: Optional[List[str]] = None,
+        auth_event_ids: Optional[List[str]] = None,
     ) -> Tuple[EventBase, EventContext]:
         """Create a new event for a local client
 
@@ -792,6 +781,11 @@ class EventCreationHandler:
 
                 If None, they will be requested from the database.
 
+            auth_event_ids:
+                The event ids to use as the auth_events for the new event.
+                Should normally be left as None, which will cause them to be calculated
+                based on the room state at the prev_events.
+
         Returns:
             Tuple of created event, context
         """
@@ -813,11 +807,30 @@ class EventCreationHandler:
             builder.type == EventTypes.Create or len(prev_event_ids) > 0
         ), "Attempting to create an event with no prev_events"
 
-        event = await builder.build(prev_event_ids=prev_event_ids)
+        event = await builder.build(
+            prev_event_ids=prev_event_ids, auth_event_ids=auth_event_ids
+        )
         context = await self.state.compute_event_context(event)
         if requester:
             context.app_service = requester.app_service
 
+        third_party_result = await self.third_party_event_rules.check_event_allowed(
+            event, context
+        )
+        if not third_party_result:
+            logger.info(
+                "Event %s forbidden by third-party rules", event,
+            )
+            raise SynapseError(
+                403, "This event is not allowed in this context", Codes.FORBIDDEN
+            )
+        elif isinstance(third_party_result, dict):
+            # the third-party rules want to replace the event. We'll need to build a new
+            # event.
+            event, context = await self._rebuild_event_after_third_party_rules(
+                third_party_result, event
+            )
+
         self.validator.validate_new(event, self.config)
 
         # If this event is an annotation then we check that that the sender
@@ -846,8 +859,11 @@ class EventCreationHandler:
         context: EventContext,
         ratelimit: bool = True,
         extra_users: List[UserID] = [],
-    ) -> int:
-        """Processes a new event. This includes checking auth, persisting it,
+        ignore_shadow_ban: bool = False,
+    ) -> EventBase:
+        """Processes a new event.
+
+        This includes deduplicating, checking auth, persisting,
         notifying users, sending to remote servers, etc.
 
         If called from a worker will hit out to the master process for final
@@ -860,10 +876,39 @@ class EventCreationHandler:
             ratelimit
             extra_users: Any extra users to notify about event
 
+            ignore_shadow_ban: True if shadow-banned users should be allowed to
+                send this event.
+
         Return:
-            The stream_id of the persisted event.
+            If the event was deduplicated, the previous, duplicate, event. Otherwise,
+            `event`.
+
+        Raises:
+            ShadowBanError if the requester has been shadow-banned.
         """
 
+        # we don't apply shadow-banning to membership events here. Invites are blocked
+        # higher up the stack, and we allow shadow-banned users to send join and leave
+        # events as normal.
+        if (
+            event.type != EventTypes.Member
+            and not ignore_shadow_ban
+            and requester.shadow_banned
+        ):
+            # We randomly sleep a bit just to annoy the requester.
+            await self.clock.sleep(random.randint(1, 10))
+            raise ShadowBanError()
+
+        if event.is_state():
+            prev_event = await self.deduplicate_state_event(event, context)
+            if prev_event is not None:
+                logger.info(
+                    "Not bothering to persist state event %s duplicated by %s",
+                    event.event_id,
+                    prev_event.event_id,
+                )
+                return prev_event
+
         if event.is_state() and (event.type, event.state_key) == (
             EventTypes.Create,
             "",
@@ -872,14 +917,6 @@ class EventCreationHandler:
         else:
             room_version = await self.store.get_room_version_id(event.room_id)
 
-        event_allowed = await self.third_party_event_rules.check_event_allowed(
-            event, context
-        )
-        if not event_allowed:
-            raise SynapseError(
-                403, "This event is not allowed in this context", Codes.FORBIDDEN
-            )
-
         if event.internal_metadata.is_out_of_band_membership():
             # the only sort of out-of-band-membership events we expect to see here
             # are invite rejections we have generated ourselves.
@@ -894,7 +931,7 @@ class EventCreationHandler:
 
         # Ensure that we can round trip before trying to persist in db
         try:
-            dump = frozendict_json_encoder.encode(event.content)
+            dump = json_encoder.encode(event.content)
             json_decoder.decode(dump)
         except Exception:
             logger.exception("Failed to encode content: %r", event.content)
@@ -917,14 +954,24 @@ class EventCreationHandler:
                     extra_users=extra_users,
                 )
                 stream_id = result["stream_id"]
-                event.internal_metadata.stream_ordering = stream_id
-                return stream_id
+                event_id = result["event_id"]
+                if event_id != event.event_id:
+                    # If we get a different event back then it means that its
+                    # been de-duplicated, so we replace the given event with the
+                    # one already persisted.
+                    event = await self.store.get_event(event_id)
+                else:
+                    # If we newly persisted the event then we need to update its
+                    # stream_ordering entry manually (as it was persisted on
+                    # another worker).
+                    event.internal_metadata.stream_ordering = stream_id
+                return event
 
-            stream_id = await self.persist_and_notify_client_event(
+            event = await self.persist_and_notify_client_event(
                 requester, event, context, ratelimit=ratelimit, extra_users=extra_users
             )
 
-            return stream_id
+            return event
         except Exception:
             # Ensure that we actually remove the entries in the push actions
             # staging area, if we calculated them.
@@ -969,11 +1016,16 @@ class EventCreationHandler:
         context: EventContext,
         ratelimit: bool = True,
         extra_users: List[UserID] = [],
-    ) -> int:
+    ) -> EventBase:
         """Called when we have fully built the event, have already
         calculated the push actions for the event, and checked auth.
 
         This should only be run on the instance in charge of persisting events.
+
+        Returns:
+            The persisted event. This may be different than the given event if
+            it was de-duplicated (e.g. because we had already persisted an
+            event with the same transaction ID.)
         """
         assert self.storage.persistence is not None
         assert self._events_shard_config.should_handle(
@@ -1021,7 +1073,7 @@ class EventCreationHandler:
 
             # Check the alias is currently valid (if it has changed).
             room_alias_str = event.content.get("alias", None)
-            directory_handler = self.hs.get_handlers().directory_handler
+            directory_handler = self.hs.get_directory_handler()
             if room_alias_str and room_alias_str != original_alias:
                 await self._validate_canonical_alias(
                     directory_handler, room_alias_str, event.room_id
@@ -1047,38 +1099,17 @@ class EventCreationHandler:
                         directory_handler, alias_str, event.room_id
                     )
 
-        federation_handler = self.hs.get_handlers().federation_handler
+        federation_handler = self.hs.get_federation_handler()
 
         if event.type == EventTypes.Member:
             if event.content["membership"] == Membership.INVITE:
-
-                def is_inviter_member_event(e):
-                    return e.type == EventTypes.Member and e.sender == event.sender
-
-                current_state_ids = await context.get_current_state_ids()
-
-                # We know this event is not an outlier, so this must be
-                # non-None.
-                assert current_state_ids is not None
-
-                state_to_include_ids = [
-                    e_id
-                    for k, e_id in current_state_ids.items()
-                    if k[0] in self.room_invite_state_types
-                    or k == (EventTypes.Member, event.sender)
-                ]
-
-                state_to_include = await self.store.get_events(state_to_include_ids)
-
-                event.unsigned["invite_room_state"] = [
-                    {
-                        "type": e.type,
-                        "state_key": e.state_key,
-                        "content": e.content,
-                        "sender": e.sender,
-                    }
-                    for e in state_to_include.values()
-                ]
+                event.unsigned[
+                    "invite_room_state"
+                ] = await self.store.get_stripped_room_state_from_event_context(
+                    context,
+                    self.room_invite_state_types,
+                    membership_user_id=event.sender,
+                )
 
                 invitee = UserID.from_string(event.state_key)
                 if not self.hs.is_mine(invitee):
@@ -1111,6 +1142,9 @@ class EventCreationHandler:
                 if original_event.room_id != event.room_id:
                     raise SynapseError(400, "Cannot redact event from a different room")
 
+                if original_event.type == EventTypes.ServerACL:
+                    raise AuthError(403, "Redacting server ACL events is not permitted")
+
             prev_state_ids = await context.get_prev_state_ids()
             auth_events_ids = self.auth.compute_auth_events(
                 event, prev_state_ids, for_verification=True
@@ -1141,9 +1175,13 @@ class EventCreationHandler:
             if prev_state_ids:
                 raise AuthError(403, "Changing the room create event is forbidden")
 
-        event_pos, max_stream_token = await self.storage.persistence.persist_event(
-            event, context=context
-        )
+        # Note that this returns the event that was persisted, which may not be
+        # the same as we passed in if it was deduplicated due transaction IDs.
+        (
+            event,
+            event_pos,
+            max_stream_token,
+        ) = await self.storage.persistence.persist_event(event, context=context)
 
         if self._ephemeral_events_enabled:
             # If there's an expiry timestamp on the event, schedule its expiry.
@@ -1164,7 +1202,7 @@ class EventCreationHandler:
             # matters as sometimes presence code can take a while.
             run_in_background(self._bump_active_time, requester.user)
 
-        return event_pos.stream
+        return event
 
     async def _bump_active_time(self, user: UserID) -> None:
         try:
@@ -1218,7 +1256,7 @@ class EventCreationHandler:
         for user_id in members:
             if not self.hs.is_mine_id(user_id):
                 continue
-            requester = create_requester(user_id)
+            requester = create_requester(user_id, authenticated_entity=self.server_name)
             try:
                 event, context = await self.create_event(
                     requester,
@@ -1235,15 +1273,10 @@ class EventCreationHandler:
 
                 # Since this is a dummy-event it is OK if it is sent by a
                 # shadow-banned user.
-                await self.send_nonmember_event(
+                await self.handle_new_client_event(
                     requester, event, context, ratelimit=False, ignore_shadow_ban=True,
                 )
                 return True
-            except ConsentNotGivenError:
-                logger.info(
-                    "Failed to send dummy event into room %s for user %s due to "
-                    "lack of consent. Will try another user" % (room_id, user_id)
-                )
             except AuthError:
                 logger.info(
                     "Failed to send dummy event into room %s for user %s due to "
@@ -1263,3 +1296,62 @@ class EventCreationHandler:
                 room_id,
             )
             del self._rooms_to_exclude_from_dummy_event_insertion[room_id]
+
+    async def _rebuild_event_after_third_party_rules(
+        self, third_party_result: dict, original_event: EventBase
+    ) -> Tuple[EventBase, EventContext]:
+        # the third_party_event_rules want to replace the event.
+        # we do some basic checks, and then return the replacement event and context.
+
+        # Construct a new EventBuilder and validate it, which helps with the
+        # rest of these checks.
+        try:
+            builder = self.event_builder_factory.for_room_version(
+                original_event.room_version, third_party_result
+            )
+            self.validator.validate_builder(builder)
+        except SynapseError as e:
+            raise Exception(
+                "Third party rules module created an invalid event: " + e.msg,
+            )
+
+        immutable_fields = [
+            # changing the room is going to break things: we've already checked that the
+            # room exists, and are holding a concurrency limiter token for that room.
+            # Also, we might need to use a different room version.
+            "room_id",
+            # changing the type or state key might work, but we'd need to check that the
+            # calling functions aren't making assumptions about them.
+            "type",
+            "state_key",
+        ]
+
+        for k in immutable_fields:
+            if getattr(builder, k, None) != original_event.get(k):
+                raise Exception(
+                    "Third party rules module created an invalid event: "
+                    "cannot change field " + k
+                )
+
+        # check that the new sender belongs to this HS
+        if not self.hs.is_mine_id(builder.sender):
+            raise Exception(
+                "Third party rules module created an invalid event: "
+                "invalid sender " + builder.sender
+            )
+
+        # copy over the original internal metadata
+        for k, v in original_event.internal_metadata.get_dict().items():
+            setattr(builder.internal_metadata, k, v)
+
+        # the event type hasn't changed, so there's no point in re-calculating the
+        # auth events.
+        event = await builder.build(
+            prev_event_ids=original_event.prev_event_ids(),
+            auth_event_ids=original_event.auth_event_ids(),
+        )
+
+        # we rebuild the event context, to be on the safe side. If nothing else,
+        # delta_ids might need an update.
+        context = await self.state.compute_event_context(event)
+        return event, context
diff --git a/synapse/handlers/oidc_handler.py b/synapse/handlers/oidc_handler.py
index 19cd652675..c605f7082a 100644
--- a/synapse/handlers/oidc_handler.py
+++ b/synapse/handlers/oidc_handler.py
@@ -12,6 +12,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import inspect
 import logging
 from typing import TYPE_CHECKING, Dict, Generic, List, Optional, Tuple, TypeVar
 from urllib.parse import urlencode
@@ -34,7 +35,8 @@ from typing_extensions import TypedDict
 from twisted.web.client import readBody
 
 from synapse.config import ConfigError
-from synapse.http.server import respond_with_html
+from synapse.handlers._base import BaseHandler
+from synapse.handlers.sso import MappingException, UserAttributes
 from synapse.http.site import SynapseRequest
 from synapse.logging.context import make_deferred_yieldable
 from synapse.types import JsonDict, UserID, map_username_to_mxid_localpart
@@ -83,19 +85,15 @@ class OidcError(Exception):
         return self.error
 
 
-class MappingException(Exception):
-    """Used to catch errors when mapping the UserInfo object
-    """
-
-
-class OidcHandler:
+class OidcHandler(BaseHandler):
     """Handles requests related to the OpenID Connect login flow.
     """
 
     def __init__(self, hs: "HomeServer"):
-        self.hs = hs
+        super().__init__(hs)
         self._callback_url = hs.config.oidc_callback_url  # type: str
         self._scopes = hs.config.oidc_scopes  # type: List[str]
+        self._user_profile_method = hs.config.oidc_user_profile_method  # type: str
         self._client_auth = ClientAuth(
             hs.config.oidc_client_id,
             hs.config.oidc_client_secret,
@@ -119,36 +117,13 @@ class OidcHandler:
         self._http_client = hs.get_proxied_http_client()
         self._auth_handler = hs.get_auth_handler()
         self._registration_handler = hs.get_registration_handler()
-        self._datastore = hs.get_datastore()
-        self._clock = hs.get_clock()
-        self._hostname = hs.hostname  # type: str
         self._server_name = hs.config.server_name  # type: str
         self._macaroon_secret_key = hs.config.macaroon_secret_key
-        self._error_template = hs.config.sso_error_template
 
         # identifier for the external_ids table
         self._auth_provider_id = "oidc"
 
-    def _render_error(
-        self, request, error: str, error_description: Optional[str] = None
-    ) -> None:
-        """Render the error template and respond to the request with it.
-
-        This is used to show errors to the user. The template of this page can
-        be found under `synapse/res/templates/sso_error.html`.
-
-        Args:
-            request: The incoming request from the browser.
-                We'll respond with an HTML page describing the error.
-            error: A technical identifier for this error. Those include
-                well-known OAuth2/OIDC error types like invalid_request or
-                access_denied.
-            error_description: A human-readable description of the error.
-        """
-        html = self._error_template.render(
-            error=error, error_description=error_description
-        )
-        respond_with_html(request, 400, html)
+        self._sso_handler = hs.get_sso_handler()
 
     def _validate_metadata(self):
         """Verifies the provider metadata.
@@ -196,11 +171,11 @@ class OidcHandler:
                     % (m["response_types_supported"],)
                 )
 
-        # If the openid scope was not requested, we need a userinfo endpoint to fetch user infos
+        # Ensure there's a userinfo endpoint to fetch from if it is required.
         if self._uses_userinfo:
             if m.get("userinfo_endpoint") is None:
                 raise ValueError(
-                    'provider has no "userinfo_endpoint", even though it is required because the "openid" scope is not requested'
+                    'provider has no "userinfo_endpoint", even though it is required'
                 )
         else:
             # If we're not using userinfo, we need a valid jwks to validate the ID token
@@ -216,12 +191,14 @@ class OidcHandler:
 
         This is based on the requested scopes: if the scopes include
         ``openid``, the provider should give use an ID token containing the
-        user informations. If not, we should fetch them using the
+        user information. If not, we should fetch them using the
         ``access_token`` with the ``userinfo_endpoint``.
         """
 
-        # Maybe that should be user-configurable and not inferred?
-        return "openid" not in self._scopes
+        return (
+            "openid" not in self._scopes
+            or self._user_profile_method == "userinfo_endpoint"
+        )
 
     async def load_metadata(self) -> OpenIDProviderMetadata:
         """Load and validate the provider metadata.
@@ -423,7 +400,7 @@ class OidcHandler:
         return resp
 
     async def _fetch_userinfo(self, token: Token) -> UserInfo:
-        """Fetch user informations from the ``userinfo_endpoint``.
+        """Fetch user information from the ``userinfo_endpoint``.
 
         Args:
             token: the token given by the ``token_endpoint``.
@@ -568,7 +545,7 @@ class OidcHandler:
 
         Since we might want to display OIDC-related errors in a user-friendly
         way, we don't raise SynapseError from here. Instead, we call
-        ``self._render_error`` which displays an HTML page for the error.
+        ``self._sso_handler.render_error`` which displays an HTML page for the error.
 
         Most of the OpenID Connect logic happens here:
 
@@ -606,7 +583,7 @@ class OidcHandler:
             if error != "access_denied":
                 logger.error("Error from the OIDC provider: %s %s", error, description)
 
-            self._render_error(request, error, description)
+            self._sso_handler.render_error(request, error, description)
             return
 
         # otherwise, it is presumably a successful response. see:
@@ -616,7 +593,9 @@ class OidcHandler:
         session = request.getCookie(SESSION_COOKIE_NAME)  # type: Optional[bytes]
         if session is None:
             logger.info("No session cookie found")
-            self._render_error(request, "missing_session", "No session cookie found")
+            self._sso_handler.render_error(
+                request, "missing_session", "No session cookie found"
+            )
             return
 
         # Remove the cookie. There is a good chance that if the callback failed
@@ -634,7 +613,9 @@ class OidcHandler:
         # Check for the state query parameter
         if b"state" not in request.args:
             logger.info("State parameter is missing")
-            self._render_error(request, "invalid_request", "State parameter is missing")
+            self._sso_handler.render_error(
+                request, "invalid_request", "State parameter is missing"
+            )
             return
 
         state = request.args[b"state"][0].decode()
@@ -648,17 +629,19 @@ class OidcHandler:
             ) = self._verify_oidc_session_token(session, state)
         except MacaroonDeserializationException as e:
             logger.exception("Invalid session")
-            self._render_error(request, "invalid_session", str(e))
+            self._sso_handler.render_error(request, "invalid_session", str(e))
             return
         except MacaroonInvalidSignatureException as e:
             logger.exception("Could not verify session")
-            self._render_error(request, "mismatching_session", str(e))
+            self._sso_handler.render_error(request, "mismatching_session", str(e))
             return
 
         # Exchange the code with the provider
         if b"code" not in request.args:
             logger.info("Code parameter is missing")
-            self._render_error(request, "invalid_request", "Code parameter is missing")
+            self._sso_handler.render_error(
+                request, "invalid_request", "Code parameter is missing"
+            )
             return
 
         logger.debug("Exchanging code")
@@ -667,7 +650,7 @@ class OidcHandler:
             token = await self._exchange_code(code)
         except OidcError as e:
             logger.exception("Could not exchange code")
-            self._render_error(request, e.error, e.error_description)
+            self._sso_handler.render_error(request, e.error, e.error_description)
             return
 
         logger.debug("Successfully obtained OAuth2 access token")
@@ -680,7 +663,7 @@ class OidcHandler:
                 userinfo = await self._fetch_userinfo(token)
             except Exception as e:
                 logger.exception("Could not fetch userinfo")
-                self._render_error(request, "fetch_error", str(e))
+                self._sso_handler.render_error(request, "fetch_error", str(e))
                 return
         else:
             logger.debug("Extracting userinfo from id_token")
@@ -688,13 +671,11 @@ class OidcHandler:
                 userinfo = await self._parse_id_token(token, nonce=nonce)
             except Exception as e:
                 logger.exception("Invalid id_token")
-                self._render_error(request, "invalid_token", str(e))
+                self._sso_handler.render_error(request, "invalid_token", str(e))
                 return
 
         # Pull out the user-agent and IP from the request.
-        user_agent = request.requestHeaders.getRawHeaders(b"User-Agent", default=[b""])[
-            0
-        ].decode("ascii", "surrogateescape")
+        user_agent = request.get_user_agent("")
         ip_address = self.hs.get_ip_from_request(request)
 
         # Call the mapper to register/login the user
@@ -704,7 +685,7 @@ class OidcHandler:
             )
         except MappingException as e:
             logger.exception("Could not map user")
-            self._render_error(request, "mapping_error", str(e))
+            self._sso_handler.render_error(request, "mapping_error", str(e))
             return
 
         # Mapping providers might not have get_extra_attributes: only call this
@@ -753,7 +734,7 @@ class OidcHandler:
                 Defaults to an hour.
 
         Returns:
-            A signed macaroon token with the session informations.
+            A signed macaroon token with the session information.
         """
         macaroon = pymacaroons.Macaroon(
             location=self._server_name, identifier="key", key=self._macaroon_secret_key,
@@ -769,7 +750,7 @@ class OidcHandler:
             macaroon.add_first_party_caveat(
                 "ui_auth_session_id = %s" % (ui_auth_session_id,)
             )
-        now = self._clock.time_msec()
+        now = self.clock.time_msec()
         expiry = now + duration_in_ms
         macaroon.add_first_party_caveat("time < %d" % (expiry,))
 
@@ -844,7 +825,7 @@ class OidcHandler:
         if not caveat.startswith(prefix):
             return False
         expiry = int(caveat[len(prefix) :])
-        now = self._clock.time_msec()
+        now = self.clock.time_msec()
         return now < expiry
 
     async def _map_userinfo_to_user(
@@ -884,71 +865,77 @@ class OidcHandler:
         # to be strings.
         remote_user_id = str(remote_user_id)
 
-        logger.info(
-            "Looking for existing mapping for user %s:%s",
+        # Older mapping providers don't accept the `failures` argument, so we
+        # try and detect support.
+        mapper_signature = inspect.signature(
+            self._user_mapping_provider.map_user_attributes
+        )
+        supports_failures = "failures" in mapper_signature.parameters
+
+        async def oidc_response_to_user_attributes(failures: int) -> UserAttributes:
+            """
+            Call the mapping provider to map the OIDC userinfo and token to user attributes.
+
+            This is backwards compatibility for abstraction for the SSO handler.
+            """
+            if supports_failures:
+                attributes = await self._user_mapping_provider.map_user_attributes(
+                    userinfo, token, failures
+                )
+            else:
+                # If the mapping provider does not support processing failures,
+                # do not continually generate the same Matrix ID since it will
+                # continue to already be in use. Note that the error raised is
+                # arbitrary and will get turned into a MappingException.
+                if failures:
+                    raise MappingException(
+                        "Mapping provider does not support de-duplicating Matrix IDs"
+                    )
+
+                attributes = await self._user_mapping_provider.map_user_attributes(  # type: ignore
+                    userinfo, token
+                )
+
+            return UserAttributes(**attributes)
+
+        async def grandfather_existing_users() -> Optional[str]:
+            if self._allow_existing_users:
+                # If allowing existing users we want to generate a single localpart
+                # and attempt to match it.
+                attributes = await oidc_response_to_user_attributes(failures=0)
+
+                user_id = UserID(attributes.localpart, self.server_name).to_string()
+                users = await self.store.get_users_by_id_case_insensitive(user_id)
+                if users:
+                    # If an existing matrix ID is returned, then use it.
+                    if len(users) == 1:
+                        previously_registered_user_id = next(iter(users))
+                    elif user_id in users:
+                        previously_registered_user_id = user_id
+                    else:
+                        # Do not attempt to continue generating Matrix IDs.
+                        raise MappingException(
+                            "Attempted to login as '{}' but it matches more than one user inexactly: {}".format(
+                                user_id, users
+                            )
+                        )
+
+                    return previously_registered_user_id
+
+            return None
+
+        return await self._sso_handler.get_mxid_from_sso(
             self._auth_provider_id,
             remote_user_id,
+            user_agent,
+            ip_address,
+            oidc_response_to_user_attributes,
+            grandfather_existing_users,
         )
 
-        registered_user_id = await self._datastore.get_user_by_external_id(
-            self._auth_provider_id, remote_user_id,
-        )
 
-        if registered_user_id is not None:
-            logger.info("Found existing mapping %s", registered_user_id)
-            return registered_user_id
-
-        try:
-            attributes = await self._user_mapping_provider.map_user_attributes(
-                userinfo, token
-            )
-        except Exception as e:
-            raise MappingException(
-                "Could not extract user attributes from OIDC response: " + str(e)
-            )
-
-        logger.debug(
-            "Retrieved user attributes from user mapping provider: %r", attributes
-        )
-
-        if not attributes["localpart"]:
-            raise MappingException("localpart is empty")
-
-        localpart = map_username_to_mxid_localpart(attributes["localpart"])
-
-        user_id = UserID(localpart, self._hostname).to_string()
-        users = await self._datastore.get_users_by_id_case_insensitive(user_id)
-        if users:
-            if self._allow_existing_users:
-                if len(users) == 1:
-                    registered_user_id = next(iter(users))
-                elif user_id in users:
-                    registered_user_id = user_id
-                else:
-                    raise MappingException(
-                        "Attempted to login as '{}' but it matches more than one user inexactly: {}".format(
-                            user_id, list(users.keys())
-                        )
-                    )
-            else:
-                # This mxid is taken
-                raise MappingException("mxid '{}' is already taken".format(user_id))
-        else:
-            # It's the first time this user is logging in and the mapped mxid was
-            # not taken, register the user
-            registered_user_id = await self._registration_handler.register_user(
-                localpart=localpart,
-                default_display_name=attributes["display_name"],
-                user_agent_ips=(user_agent, ip_address),
-            )
-        await self._datastore.record_user_external_id(
-            self._auth_provider_id, remote_user_id, registered_user_id,
-        )
-        return registered_user_id
-
-
-UserAttribute = TypedDict(
-    "UserAttribute", {"localpart": str, "display_name": Optional[str]}
+UserAttributeDict = TypedDict(
+    "UserAttributeDict", {"localpart": str, "display_name": Optional[str]}
 )
 C = TypeVar("C")
 
@@ -991,13 +978,15 @@ class OidcMappingProvider(Generic[C]):
         raise NotImplementedError()
 
     async def map_user_attributes(
-        self, userinfo: UserInfo, token: Token
-    ) -> UserAttribute:
+        self, userinfo: UserInfo, token: Token, failures: int
+    ) -> UserAttributeDict:
         """Map a `UserInfo` object into user attributes.
 
         Args:
             userinfo: An object representing the user given by the OIDC provider
             token: A dict with the tokens returned by the provider
+            failures: How many times a call to this function with this
+                UserInfo has resulted in a failure.
 
         Returns:
             A dict containing the ``localpart`` and (optionally) the ``display_name``
@@ -1097,10 +1086,17 @@ class JinjaOidcMappingProvider(OidcMappingProvider[JinjaOidcMappingConfig]):
         return userinfo[self._config.subject_claim]
 
     async def map_user_attributes(
-        self, userinfo: UserInfo, token: Token
-    ) -> UserAttribute:
+        self, userinfo: UserInfo, token: Token, failures: int
+    ) -> UserAttributeDict:
         localpart = self._config.localpart_template.render(user=userinfo).strip()
 
+        # Ensure only valid characters are included in the MXID.
+        localpart = map_username_to_mxid_localpart(localpart)
+
+        # Append suffix integer if last call to this function failed to produce
+        # a usable mxid.
+        localpart += str(failures) if failures else ""
+
         display_name = None  # type: Optional[str]
         if self._config.display_name_template is not None:
             display_name = self._config.display_name_template.render(
@@ -1110,7 +1106,7 @@ class JinjaOidcMappingProvider(OidcMappingProvider[JinjaOidcMappingConfig]):
             if display_name == "":
                 display_name = None
 
-        return UserAttribute(localpart=localpart, display_name=display_name)
+        return UserAttributeDict(localpart=localpart, display_name=display_name)
 
     async def get_extra_attributes(self, userinfo: UserInfo, token: Token) -> JsonDict:
         extras = {}  # type: Dict[str, str]
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py
index 2c2a633938..5372753707 100644
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -92,7 +92,7 @@ class PaginationHandler:
         self._retention_allowed_lifetime_min = hs.config.retention_allowed_lifetime_min
         self._retention_allowed_lifetime_max = hs.config.retention_allowed_lifetime_max
 
-        if hs.config.retention_enabled:
+        if hs.config.run_background_tasks and hs.config.retention_enabled:
             # Run the purge jobs described in the configuration file.
             for job in hs.config.retention_purge_jobs:
                 logger.info("Setting up purge job with config: %s", job)
@@ -299,17 +299,22 @@ class PaginationHandler:
         """
         return self._purges_by_id.get(purge_id)
 
-    async def purge_room(self, room_id: str) -> None:
-        """Purge the given room from the database"""
+    async def purge_room(self, room_id: str, force: bool = False) -> None:
+        """Purge the given room from the database.
+
+        Args:
+            room_id: room to be purged
+            force: set true to skip checking for joined users.
+        """
         with await self.pagination_lock.write(room_id):
             # check we know about the room
             await self.store.get_room_version_id(room_id)
 
             # first check that we have no users in this room
-            joined = await self.store.is_host_joined(room_id, self._server_name)
-
-            if joined:
-                raise SynapseError(400, "Users are still joined to this room")
+            if not force:
+                joined = await self.store.is_host_joined(room_id, self._server_name)
+                if joined:
+                    raise SynapseError(400, "Users are still joined to this room")
 
             await self.storage.purge_events.purge_room(room_id)
 
@@ -383,7 +388,7 @@ class PaginationHandler:
                             "room_key", leave_token
                         )
 
-                await self.hs.get_handlers().federation_handler.maybe_backfill(
+                await self.hs.get_federation_handler().maybe_backfill(
                     room_id, curr_topo, limit=pagin_config.limit,
                 )
 
diff --git a/synapse/handlers/password_policy.py b/synapse/handlers/password_policy.py
index 88e2f87200..6c635cc31b 100644
--- a/synapse/handlers/password_policy.py
+++ b/synapse/handlers/password_policy.py
@@ -16,14 +16,18 @@
 
 import logging
 import re
+from typing import TYPE_CHECKING
 
 from synapse.api.errors import Codes, PasswordRefusedError
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
 class PasswordPolicyHandler:
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         self.policy = hs.config.password_policy
         self.enabled = hs.config.password_policy_enabled
 
@@ -33,11 +37,11 @@ class PasswordPolicyHandler:
         self.regexp_uppercase = re.compile("[A-Z]")
         self.regexp_lowercase = re.compile("[a-z]")
 
-    def validate_password(self, password):
+    def validate_password(self, password: str) -> None:
         """Checks whether a given password complies with the server's policy.
 
         Args:
-            password (str): The password to check against the server's policy.
+            password: The password to check against the server's policy.
 
         Raises:
             PasswordRefusedError: The password doesn't comply with the server's policy.
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 1000ac95ff..22d1e9d35c 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -25,7 +25,7 @@ The methods that define policy are:
 import abc
 import logging
 from contextlib import contextmanager
-from typing import Dict, Iterable, List, Set, Tuple
+from typing import TYPE_CHECKING, Dict, Iterable, List, Set, Tuple
 
 from prometheus_client import Counter
 from typing_extensions import ContextManager
@@ -46,9 +46,8 @@ from synapse.util.caches.descriptors import cached
 from synapse.util.metrics import Measure
 from synapse.util.wheel_timer import WheelTimer
 
-MYPY = False
-if MYPY:
-    import synapse.server
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
 
 logger = logging.getLogger(__name__)
 
@@ -101,7 +100,7 @@ assert LAST_ACTIVE_GRANULARITY < IDLE_TIMER
 class BasePresenceHandler(abc.ABC):
     """Parts of the PresenceHandler that are shared between workers and master"""
 
-    def __init__(self, hs: "synapse.server.HomeServer"):
+    def __init__(self, hs: "HomeServer"):
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
 
@@ -199,7 +198,7 @@ class BasePresenceHandler(abc.ABC):
 
 
 class PresenceHandler(BasePresenceHandler):
-    def __init__(self, hs: "synapse.server.HomeServer"):
+    def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
         self.hs = hs
         self.is_mine_id = hs.is_mine_id
@@ -802,7 +801,7 @@ class PresenceHandler(BasePresenceHandler):
             between the requested tokens due to the limit.
 
             The token returned can be used in a subsequent call to this
-            function to get further updatees.
+            function to get further updates.
 
             The updates are a list of 2-tuples of stream ID and the row data
         """
@@ -977,7 +976,7 @@ def should_notify(old_state, new_state):
             new_state.last_active_ts - old_state.last_active_ts
             > LAST_ACTIVE_GRANULARITY
         ):
-            # Only notify about last active bumps if we're not currently acive
+            # Only notify about last active bumps if we're not currently active
             if not new_state.currently_active:
                 notify_reason_counter.labels("last_active_change_online").inc()
                 return True
@@ -1011,7 +1010,7 @@ def format_user_presence_state(state, now, include_user_id=True):
 
 
 class PresenceEventSource:
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         # We can't call get_presence_handler here because there's a cycle:
         #
         #   Presence -> Notifier -> PresenceEventSource -> Presence
@@ -1071,12 +1070,14 @@ class PresenceEventSource:
 
             users_interested_in = await self._get_interested_in(user, explicit_room_id)
 
-            user_ids_changed = set()
+            user_ids_changed = set()  # type: Collection[str]
             changed = None
             if from_key:
                 changed = stream_change_cache.get_all_entities_changed(from_key)
 
             if changed is not None and len(changed) < 500:
+                assert isinstance(user_ids_changed, set)
+
                 # For small deltas, its quicker to get all changes and then
                 # work out if we share a room or they're in our presence list
                 get_updates_counter.labels("stream").inc()
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index c301ac0631..40b1c25a36 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -13,10 +13,9 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import logging
 import random
-from typing import List
+from typing import TYPE_CHECKING, List, Optional
 
 from signedjson.sign import sign_json
 
@@ -31,28 +30,42 @@ from synapse.api.errors import (
     SynapseError,
 )
 from synapse.logging.context import run_in_background
-from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.types import UserID, create_requester, get_domain_from_id
+from synapse.metrics.background_process_metrics import (
+    run_as_background_process,
+    wrap_as_background_process,
+)
+from synapse.types import (
+    JsonDict,
+    Requester,
+    UserID,
+    create_requester,
+    get_domain_from_id,
+)
 
 from ._base import BaseHandler
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 MAX_DISPLAYNAME_LEN = 256
 MAX_AVATAR_URL_LEN = 1000
 
 
-class BaseProfileHandler(BaseHandler):
+class ProfileHandler(BaseHandler):
     """Handles fetching and updating user profile information.
 
-    BaseProfileHandler can be instantiated directly on workers and will
-    delegate to master when necessary. The master process should use the
-    subclass MasterProfileHandler
+    ProfileHandler can be instantiated directly on workers and will
+    delegate to master when necessary.
     """
 
+    PROFILE_UPDATE_MS = 60 * 1000
+    PROFILE_UPDATE_EVERY_MS = 24 * 60 * 60 * 1000
+
     PROFILE_REPLICATE_INTERVAL = 2 * 60 * 1000
 
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
 
         self.federation = hs.get_federation_client()
@@ -68,9 +81,9 @@ class BaseProfileHandler(BaseHandler):
         self.allowed_avatar_mimetypes = hs.config.allowed_avatar_mimetypes
         self.replicate_user_profiles_to = hs.config.replicate_user_profiles_to
 
-        if hs.config.worker_app is None:
+        if hs.config.run_background_tasks:
             self.clock.looping_call(
-                self._start_update_remote_profile_cache, self.PROFILE_UPDATE_MS
+                self._update_remote_profile_cache, self.PROFILE_UPDATE_MS
             )
 
             if len(self.hs.config.replicate_user_profiles_to) > 0:
@@ -154,7 +167,7 @@ class BaseProfileHandler(BaseHandler):
             )
             raise
 
-    async def get_profile(self, user_id):
+    async def get_profile(self, user_id: str) -> JsonDict:
         target_user = UserID.from_string(user_id)
 
         if self.hs.is_mine(target_user):
@@ -183,11 +196,18 @@ class BaseProfileHandler(BaseHandler):
             except RequestSendFailed as e:
                 raise SynapseError(502, "Failed to fetch profile") from e
             except HttpResponseException as e:
+                if e.code < 500 and e.code != 404:
+                    # Other codes are not allowed in c2s API
+                    logger.info(
+                        "Server replied with wrong response: %s %s", e.code, e.msg
+                    )
+
+                    raise SynapseError(502, "Failed to fetch profile")
                 raise e.to_synapse_error()
 
-    async def get_profile_from_cache(self, user_id):
+    async def get_profile_from_cache(self, user_id: str) -> JsonDict:
         """Get the profile information from our local cache. If the user is
-        ours then the profile information will always be corect. Otherwise,
+        ours then the profile information will always be correct. Otherwise,
         it may be out of date/missing.
         """
         target_user = UserID.from_string(user_id)
@@ -209,7 +229,7 @@ class BaseProfileHandler(BaseHandler):
             profile = await self.store.get_from_remote_profile_cache(user_id)
             return profile or {}
 
-    async def get_displayname(self, target_user):
+    async def get_displayname(self, target_user: UserID) -> Optional[str]:
         if self.hs.is_mine(target_user):
             try:
                 displayname = await self.store.get_profile_displayname(
@@ -237,20 +257,24 @@ class BaseProfileHandler(BaseHandler):
             return result["displayname"]
 
     async def set_displayname(
-        self, target_user, requester, new_displayname, by_admin=False
-    ):
+        self,
+        target_user: UserID,
+        requester: Requester,
+        new_displayname: str,
+        by_admin: bool = False,
+    ) -> None:
         """Set the displayname of a user
 
         Args:
-            target_user (UserID): the user whose displayname is to be changed.
-            requester (Requester): The user attempting to make this change.
-            new_displayname (str): The displayname to give this user.
-            by_admin (bool): Whether this change was made by an administrator.
+            target_user: the user whose displayname is to be changed.
+            requester: The user attempting to make this change.
+            new_displayname: The displayname to give this user.
+            by_admin: Whether this change was made by an administrator.
         """
         if not self.hs.is_mine(target_user):
             raise SynapseError(400, "User is not hosted on this homeserver")
 
-        if not by_admin and requester and target_user != requester.user:
+        if not by_admin and target_user != requester.user:
             raise AuthError(400, "Cannot set another user's displayname")
 
         if not by_admin and not self.hs.config.enable_set_displayname:
@@ -263,15 +287,26 @@ class BaseProfileHandler(BaseHandler):
                 )
 
         if not isinstance(new_displayname, str):
-            raise SynapseError(400, "Invalid displayname")
+            raise SynapseError(
+                400, "'displayname' must be a string", errcode=Codes.INVALID_PARAM
+            )
 
         if len(new_displayname) > MAX_DISPLAYNAME_LEN:
             raise SynapseError(
                 400, "Displayname is too long (max %i)" % (MAX_DISPLAYNAME_LEN,)
             )
 
+        displayname_to_set = new_displayname  # type: Optional[str]
         if new_displayname == "":
-            new_displayname = None
+            displayname_to_set = None
+
+        # If the admin changes the display name of a user, the requesting user cannot send
+        # the join event to update the displayname in the rooms.
+        # This must be done by the target user himself.
+        if by_admin:
+            requester = create_requester(
+                target_user, authenticated_entity=requester.authenticated_entity,
+            )
 
         if len(self.hs.config.replicate_user_profiles_to) > 0:
             cur_batchnum = (
@@ -281,14 +316,8 @@ class BaseProfileHandler(BaseHandler):
         else:
             new_batchnum = None
 
-        # If the admin changes the display name of a user, the requesting user cannot send
-        # the join event to update the displayname in the rooms.
-        # This must be done by the target user himself.
-        if by_admin:
-            requester = create_requester(target_user)
-
         await self.store.set_profile_displayname(
-            target_user.localpart, new_displayname, new_batchnum
+            target_user.localpart, displayname_to_set, new_batchnum
         )
 
         if self.hs.config.user_directory_search_all_users:
@@ -339,7 +368,7 @@ class BaseProfileHandler(BaseHandler):
         # start a profile replication push
         run_in_background(self._replicate_profiles)
 
-    async def get_avatar_url(self, target_user):
+    async def get_avatar_url(self, target_user: UserID) -> Optional[str]:
         if self.hs.is_mine(target_user):
             try:
                 avatar_url = await self.store.get_profile_avatar_url(
@@ -366,15 +395,19 @@ class BaseProfileHandler(BaseHandler):
             return result["avatar_url"]
 
     async def set_avatar_url(
-        self, target_user, requester, new_avatar_url, by_admin=False
+        self,
+        target_user: UserID,
+        requester: Requester,
+        new_avatar_url: str,
+        by_admin: bool = False,
     ):
         """Set a new avatar URL for a user.
 
         Args:
-            target_user (UserID): the user whose avatar URL is to be changed.
-            requester (Requester): The user attempting to make this change.
-            new_avatar_url (str): The avatar URL to give this user.
-            by_admin (bool): Whether this change was made by an administrator.
+            target_user: the user whose avatar URL is to be changed.
+            requester: The user attempting to make this change.
+            new_avatar_url: The avatar URL to give this user.
+            by_admin: Whether this change was made by an administrator.
         """
         if not self.hs.is_mine(target_user):
             raise SynapseError(400, "User is not hosted on this homeserver")
@@ -390,7 +423,9 @@ class BaseProfileHandler(BaseHandler):
                 )
 
         if not isinstance(new_avatar_url, str):
-            raise SynapseError(400, "Invalid displayname")
+            raise SynapseError(
+                400, "'avatar_url' must be a string", errcode=Codes.INVALID_PARAM
+            )
 
         if len(new_avatar_url) > MAX_AVATAR_URL_LEN:
             raise SynapseError(
@@ -429,7 +464,9 @@ class BaseProfileHandler(BaseHandler):
 
         # Same like set_displayname
         if by_admin:
-            requester = create_requester(target_user)
+            requester = create_requester(
+                target_user, authenticated_entity=requester.authenticated_entity
+            )
 
         if len(self.hs.config.replicate_user_profiles_to) > 0:
             cur_batchnum = (
@@ -468,7 +505,7 @@ class BaseProfileHandler(BaseHandler):
             raise SynapseError(400, "Invalid avatar URL '%s' supplied" % mxc)
         return avatar_pieces[-1]
 
-    async def on_profile_query(self, args):
+    async def on_profile_query(self, args: JsonDict) -> JsonDict:
         user = UserID.from_string(args["user_id"])
         if not self.hs.is_mine(user):
             raise SynapseError(400, "User is not hosted on this homeserver")
@@ -493,7 +530,9 @@ class BaseProfileHandler(BaseHandler):
 
         return response
 
-    async def _update_join_states(self, requester, target_user):
+    async def _update_join_states(
+        self, requester: Requester, target_user: UserID
+    ) -> None:
         if not self.hs.is_mine(target_user):
             return
 
@@ -524,15 +563,17 @@ class BaseProfileHandler(BaseHandler):
                     "Failed to update join event for room %s - %s", room_id, str(e)
                 )
 
-    async def check_profile_query_allowed(self, target_user, requester=None):
+    async def check_profile_query_allowed(
+        self, target_user: UserID, requester: Optional[UserID] = None
+    ) -> None:
         """Checks whether a profile query is allowed. If the
         'require_auth_for_profile_requests' config flag is set to True and a
         'requester' is provided, the query is only allowed if the two users
         share a room.
 
         Args:
-            target_user (UserID): The owner of the queried profile.
-            requester (None|UserID): The user querying for the profile.
+            target_user: The owner of the queried profile.
+            requester: The user querying for the profile.
 
         Raises:
             SynapseError(403): The two users share no room, or ne user couldn't
@@ -571,25 +612,7 @@ class BaseProfileHandler(BaseHandler):
                 raise SynapseError(403, "Profile isn't available", Codes.FORBIDDEN)
             raise
 
-
-class MasterProfileHandler(BaseProfileHandler):
-    PROFILE_UPDATE_MS = 60 * 1000
-    PROFILE_UPDATE_EVERY_MS = 24 * 60 * 60 * 1000
-
-    def __init__(self, hs):
-        super().__init__(hs)
-
-        assert hs.config.worker_app is None
-
-        self.clock.looping_call(
-            self._start_update_remote_profile_cache, self.PROFILE_UPDATE_MS
-        )
-
-    def _start_update_remote_profile_cache(self):
-        return run_as_background_process(
-            "Update remote profile", self._update_remote_profile_cache
-        )
-
+    @wrap_as_background_process("Update remote profile")
     async def _update_remote_profile_cache(self):
         """Called periodically to check profiles of remote users we haven't
         checked in a while.
diff --git a/synapse/handlers/read_marker.py b/synapse/handlers/read_marker.py
index c32f314a1c..a7550806e6 100644
--- a/synapse/handlers/read_marker.py
+++ b/synapse/handlers/read_marker.py
@@ -14,23 +14,29 @@
 # limitations under the License.
 
 import logging
+from typing import TYPE_CHECKING
 
 from synapse.util.async_helpers import Linearizer
 
 from ._base import BaseHandler
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
 class ReadMarkerHandler(BaseHandler):
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
         self.server_name = hs.config.server_name
         self.store = hs.get_datastore()
         self.read_marker_linearizer = Linearizer(name="read_marker")
         self.notifier = hs.get_notifier()
 
-    async def received_client_read_marker(self, room_id, user_id, event_id):
+    async def received_client_read_marker(
+        self, room_id: str, user_id: str, event_id: str
+    ) -> None:
         """Updates the read marker for a given user in a given room if the event ID given
         is ahead in the stream relative to the current read marker.
 
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index 7225923757..153cbae7b9 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -13,9 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
+from typing import List, Tuple
 
+from synapse.appservice import ApplicationService
 from synapse.handlers._base import BaseHandler
-from synapse.types import ReadReceipt, get_domain_from_id
+from synapse.types import JsonDict, ReadReceipt, get_domain_from_id
 from synapse.util.async_helpers import maybe_awaitable
 
 logger = logging.getLogger(__name__)
@@ -140,5 +142,37 @@ class ReceiptEventSource:
 
         return (events, to_key)
 
+    async def get_new_events_as(
+        self, from_key: int, service: ApplicationService
+    ) -> Tuple[List[JsonDict], int]:
+        """Returns a set of new receipt events that an appservice
+        may be interested in.
+
+        Args:
+            from_key: the stream position at which events should be fetched from
+            service: The appservice which may be interested
+        """
+        from_key = int(from_key)
+        to_key = self.get_current_key()
+
+        if from_key == to_key:
+            return [], to_key
+
+        # Fetch all read receipts for all rooms, up to a limit of 100. This is ordered
+        # by most recent.
+        rooms_to_events = await self.store.get_linearized_receipts_for_all_rooms(
+            from_key=from_key, to_key=to_key
+        )
+
+        # Then filter down to rooms that the AS can read
+        events = []
+        for room_id, event in rooms_to_events.items():
+            if not await service.matches_user_in_member_list(room_id, self.store):
+                continue
+
+            events.append(event)
+
+        return (events, to_key)
+
     def get_current_key(self, direction="f"):
         return self.store.get_max_receipt_stream_id()
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index a26d821b53..c227c4fe91 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -15,10 +15,12 @@
 
 """Contains functions for registering clients."""
 import logging
+from typing import TYPE_CHECKING, List, Optional, Tuple
 
 from synapse import types
 from synapse.api.constants import MAX_USERID_LENGTH, EventTypes, JoinRules, LoginType
 from synapse.api.errors import AuthError, Codes, ConsentNotGivenError, SynapseError
+from synapse.appservice import ApplicationService
 from synapse.config.server import is_threepid_reserved
 from synapse.http.servlet import assert_params_in_dict
 from synapse.replication.http.login import RegisterDeviceReplicationServlet
@@ -32,16 +34,14 @@ from synapse.types import RoomAlias, UserID, create_requester
 
 from ._base import BaseHandler
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
 class RegistrationHandler(BaseHandler):
-    def __init__(self, hs):
-        """
-
-        Args:
-            hs (synapse.server.HomeServer):
-        """
+    def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
         self.hs = hs
         self.auth = hs.get_auth()
@@ -49,10 +49,11 @@ class RegistrationHandler(BaseHandler):
         self.profile_handler = hs.get_profile_handler()
         self.user_directory_handler = hs.get_user_directory_handler()
         self.http_client = hs.get_simple_http_client()
-        self.identity_handler = self.hs.get_handlers().identity_handler
+        self.identity_handler = self.hs.get_identity_handler()
         self.ratelimiter = hs.get_registration_ratelimiter()
         self.macaroon_gen = hs.get_macaroon_generator()
         self._server_notices_mxid = hs.config.server_notices_mxid
+        self._server_name = hs.hostname
 
         self.spam_checker = hs.get_spam_checker()
 
@@ -73,7 +74,10 @@ class RegistrationHandler(BaseHandler):
         self.session_lifetime = hs.config.session_lifetime
 
     async def check_username(
-        self, localpart, guest_access_token=None, assigned_user_id=None,
+        self,
+        localpart: str,
+        guest_access_token: Optional[str] = None,
+        assigned_user_id: Optional[str] = None,
     ):
         """
 
@@ -130,7 +134,10 @@ class RegistrationHandler(BaseHandler):
 
             # Retrieve guest user information from provided access token
             user_data = await self.auth.get_user_by_access_token(guest_access_token)
-            if not user_data["is_guest"] or user_data["user"].localpart != localpart:
+            if (
+                not user_data.is_guest
+                or UserID.from_string(user_data.user_id).localpart != localpart
+            ):
                 raise AuthError(
                     403,
                     "Cannot register taken user ID without valid guest "
@@ -151,39 +158,45 @@ class RegistrationHandler(BaseHandler):
 
     async def register_user(
         self,
-        localpart=None,
-        password_hash=None,
-        guest_access_token=None,
-        make_guest=False,
-        admin=False,
-        threepid=None,
-        user_type=None,
-        default_display_name=None,
-        address=None,
-        bind_emails=[],
-        by_admin=False,
-        user_agent_ips=None,
-    ):
+        localpart: Optional[str] = None,
+        password_hash: Optional[str] = None,
+        guest_access_token: Optional[str] = None,
+        make_guest: bool = False,
+        admin: bool = False,
+        threepid: Optional[dict] = None,
+        user_type: Optional[str] = None,
+        default_display_name: Optional[str] = None,
+        address: Optional[str] = None,
+        bind_emails: List[str] = [],
+        by_admin: bool = False,
+        user_agent_ips: Optional[List[Tuple[str, str]]] = None,
+    ) -> str:
         """Registers a new client on the server.
 
         Args:
             localpart: The local part of the user ID to register. If None,
               one will be generated.
-            password_hash (str|None): The hashed password to assign to this user so they can
+            password_hash: The hashed password to assign to this user so they can
               login again. This can be None which means they cannot login again
               via a password (e.g. the user is an application service user).
-            user_type (str|None): type of user. One of the values from
+            guest_access_token: The access token used when this was a guest
+                account.
+            make_guest: True if the the new user should be guest,
+                false to add a regular user account.
+            admin: True if the user should be registered as a server admin.
+            threepid: The threepid used for registering, if any.
+            user_type: type of user. One of the values from
               api.constants.UserTypes, or None for a normal user.
-            default_display_name (unicode|None): if set, the new user's displayname
+            default_display_name: if set, the new user's displayname
               will be set to this. Defaults to 'localpart'.
-            address (str|None): the IP address used to perform the registration.
-            bind_emails (List[str]): list of emails to bind to this account.
-            by_admin (bool): True if this registration is being made via the
+            address: the IP address used to perform the registration.
+            bind_emails: list of emails to bind to this account.
+            by_admin: True if this registration is being made via the
               admin api, otherwise False.
-            user_agent_ips (List[(str, str)]): Tuples of IP addresses and user-agents used
+            user_agent_ips: Tuples of IP addresses and user-agents used
                 during the registration process.
         Returns:
-            str: user_id
+            The registere user_id.
         Raises:
             SynapseError if there was a problem registering.
         """
@@ -239,8 +252,9 @@ class RegistrationHandler(BaseHandler):
             )
 
             if default_display_name:
+                requester = create_requester(user)
                 await self.profile_handler.set_displayname(
-                    user, None, default_display_name, by_admin=True
+                    user, requester, default_display_name, by_admin=True
                 )
 
             if self.hs.config.user_directory_search_all_users:
@@ -252,8 +266,10 @@ class RegistrationHandler(BaseHandler):
         else:
             # autogen a sequential user ID
             fail_count = 0
-            user = None
-            while not user:
+            # If a default display name is not given, generate one.
+            generate_display_name = default_display_name is None
+            # This breaks on successful registration *or* errors after 10 failures.
+            while True:
                 # Fail after being unable to find a suitable ID a few times
                 if fail_count > 10:
                     raise SynapseError(500, "Unable to find a suitable guest user ID")
@@ -262,7 +278,7 @@ class RegistrationHandler(BaseHandler):
                 user = UserID(localpart, self.hs.hostname)
                 user_id = user.to_string()
                 self.check_user_id_not_appservice_exclusive(user_id)
-                if default_display_name is None:
+                if generate_display_name:
                     default_display_name = localpart
                 try:
                     await self.register_with_store(
@@ -274,16 +290,15 @@ class RegistrationHandler(BaseHandler):
                         shadow_banned=shadow_banned,
                     )
 
+                    requester = create_requester(user)
                     await self.profile_handler.set_displayname(
-                        user, None, default_display_name, by_admin=True
+                        user, requester, default_display_name, by_admin=True
                     )
 
                     # Successfully registered
                     break
                 except SynapseError:
                     # if user id is taken, just generate another
-                    user = None
-                    user_id = None
                     fail_count += 1
 
         if not self.hs.config.user_consent_at_registration:
@@ -323,7 +338,7 @@ class RegistrationHandler(BaseHandler):
 
         return user_id
 
-    async def _create_and_join_rooms(self, user_id: str):
+    async def _create_and_join_rooms(self, user_id: str) -> None:
         """
         Create the auto-join rooms and join or invite the user to them.
 
@@ -346,7 +361,8 @@ class RegistrationHandler(BaseHandler):
         requires_join = False
         if self.hs.config.registration.auto_join_user_id:
             fake_requester = create_requester(
-                self.hs.config.registration.auto_join_user_id
+                self.hs.config.registration.auto_join_user_id,
+                authenticated_entity=self._server_name,
             )
 
             # If the room requires an invite, add the user to the list of invites.
@@ -358,7 +374,9 @@ class RegistrationHandler(BaseHandler):
             # being necessary this will occur after the invite was sent.
             requires_join = True
         else:
-            fake_requester = create_requester(user_id)
+            fake_requester = create_requester(
+                user_id, authenticated_entity=self._server_name
+            )
 
         # Choose whether to federate the new room.
         if not self.hs.config.registration.autocreate_auto_join_rooms_federated:
@@ -391,7 +409,9 @@ class RegistrationHandler(BaseHandler):
                     # created it, then ensure the first user joins it.
                     if requires_join:
                         await room_member_handler.update_membership(
-                            requester=create_requester(user_id),
+                            requester=create_requester(
+                                user_id, authenticated_entity=self._server_name
+                            ),
                             target=UserID.from_string(user_id),
                             room_id=info["room_id"],
                             # Since it was just created, there are no remote hosts.
@@ -399,15 +419,10 @@ class RegistrationHandler(BaseHandler):
                             action="join",
                             ratelimit=False,
                         )
-
-            except ConsentNotGivenError as e:
-                # Technically not necessary to pull out this error though
-                # moving away from bare excepts is a good thing to do.
-                logger.error("Failed to join new user to %r: %r", r, e)
             except Exception as e:
                 logger.error("Failed to join new user to %r: %r", r, e)
 
-    async def _join_rooms(self, user_id: str):
+    async def _join_rooms(self, user_id: str) -> None:
         """
         Join or invite the user to the auto-join rooms.
 
@@ -453,9 +468,13 @@ class RegistrationHandler(BaseHandler):
 
                 # Send the invite, if necessary.
                 if requires_invite:
+                    # If an invite is required, there must be a auto-join user ID.
+                    assert self.hs.config.registration.auto_join_user_id
+
                     await room_member_handler.update_membership(
                         requester=create_requester(
-                            self.hs.config.registration.auto_join_user_id
+                            self.hs.config.registration.auto_join_user_id,
+                            authenticated_entity=self._server_name,
                         ),
                         target=UserID.from_string(user_id),
                         room_id=room_id,
@@ -466,7 +485,9 @@ class RegistrationHandler(BaseHandler):
 
                 # Send the join.
                 await room_member_handler.update_membership(
-                    requester=create_requester(user_id),
+                    requester=create_requester(
+                        user_id, authenticated_entity=self._server_name
+                    ),
                     target=UserID.from_string(user_id),
                     room_id=room_id,
                     remote_room_hosts=remote_room_hosts,
@@ -481,7 +502,7 @@ class RegistrationHandler(BaseHandler):
             except Exception as e:
                 logger.error("Failed to join new user to %r: %r", r, e)
 
-    async def _auto_join_rooms(self, user_id: str):
+    async def _auto_join_rooms(self, user_id: str) -> None:
         """Automatically joins users to auto join rooms - creating the room in the first place
         if the user is the first to be created.
 
@@ -504,17 +525,17 @@ class RegistrationHandler(BaseHandler):
         else:
             await self._join_rooms(user_id)
 
-    async def post_consent_actions(self, user_id):
+    async def post_consent_actions(self, user_id: str) -> None:
         """A series of registration actions that can only be carried out once consent
         has been granted
 
         Args:
-            user_id (str): The user to join
+            user_id: The user to join
         """
         await self._auto_join_rooms(user_id)
 
     async def appservice_register(
-        self, user_localpart, as_token, password_hash, display_name
+        self, user_localpart: str, as_token: str, password_hash: str, display_name: str
     ):
         # FIXME: this should be factored out and merged with normal register()
         user = UserID(user_localpart, self.hs.hostname)
@@ -542,8 +563,9 @@ class RegistrationHandler(BaseHandler):
             create_profile_with_displayname=display_name,
         )
 
+        requester = create_requester(user)
         await self.profile_handler.set_displayname(
-            user, None, display_name, by_admin=True
+            user, requester, display_name, by_admin=True
         )
 
         if self.hs.config.user_directory_search_all_users:
@@ -554,7 +576,9 @@ class RegistrationHandler(BaseHandler):
 
         return user_id
 
-    def check_user_id_not_appservice_exclusive(self, user_id, allowed_appservice=None):
+    def check_user_id_not_appservice_exclusive(
+        self, user_id: str, allowed_appservice: Optional[ApplicationService] = None
+    ) -> None:
         # don't allow people to register the server notices mxid
         if self._server_notices_mxid is not None:
             if user_id == self._server_notices_mxid:
@@ -609,24 +633,12 @@ class RegistrationHandler(BaseHandler):
             },
         )
 
-    async def _generate_user_id(self):
-        if self._next_generated_user_id is None:
-            with await self._generate_user_id_linearizer.queue(()):
-                if self._next_generated_user_id is None:
-                    self._next_generated_user_id = (
-                        await self.store.find_next_generated_user_id_localpart()
-                    )
-
-        id = self._next_generated_user_id
-        self._next_generated_user_id += 1
-        return str(id)
-
-    def check_registration_ratelimit(self, address):
+    def check_registration_ratelimit(self, address: Optional[str]) -> None:
         """A simple helper method to check whether the registration rate limit has been hit
         for a given IP address
 
         Args:
-            address (str|None): the IP address used to perform the registration. If this is
+            address: the IP address used to perform the registration. If this is
                 None, no ratelimiting will be performed.
 
         Raises:
@@ -637,42 +649,39 @@ class RegistrationHandler(BaseHandler):
 
         self.ratelimiter.ratelimit(address)
 
-    def register_with_store(
+    async def register_with_store(
         self,
-        user_id,
-        password_hash=None,
-        was_guest=False,
-        make_guest=False,
-        appservice_id=None,
-        create_profile_with_displayname=None,
-        admin=False,
-        user_type=None,
-        address=None,
-        shadow_banned=False,
-    ):
+        user_id: str,
+        password_hash: Optional[str] = None,
+        was_guest: bool = False,
+        make_guest: bool = False,
+        appservice_id: Optional[str] = None,
+        create_profile_with_displayname: Optional[str] = None,
+        admin: bool = False,
+        user_type: Optional[str] = None,
+        address: Optional[str] = None,
+        shadow_banned: bool = False,
+    ) -> None:
         """Register user in the datastore.
 
         Args:
-            user_id (str): The desired user ID to register.
-            password_hash (str|None): Optional. The password hash for this user.
-            was_guest (bool): Optional. Whether this is a guest account being
+            user_id: The desired user ID to register.
+            password_hash: Optional. The password hash for this user.
+            was_guest: Optional. Whether this is a guest account being
                 upgraded to a non-guest account.
-            make_guest (boolean): True if the the new user should be guest,
+            make_guest: True if the the new user should be guest,
                 false to add a regular user account.
-            appservice_id (str|None): The ID of the appservice registering the user.
-            create_profile_with_displayname (unicode|None): Optionally create a
+            appservice_id: The ID of the appservice registering the user.
+            create_profile_with_displayname: Optionally create a
                 profile for the user, setting their displayname to the given value
-            admin (boolean): is an admin user?
-            user_type (str|None): type of user. One of the values from
+            admin: is an admin user?
+            user_type: type of user. One of the values from
                 api.constants.UserTypes, or None for a normal user.
-            address (str|None): the IP address used to perform the registration.
-            shadow_banned (bool): Whether to shadow-ban the user
-
-        Returns:
-            Awaitable
+            address: the IP address used to perform the registration.
+            shadow_banned: Whether to shadow-ban the user
         """
         if self.hs.config.worker_app:
-            return self._register_client(
+            await self._register_client(
                 user_id=user_id,
                 password_hash=password_hash,
                 was_guest=was_guest,
@@ -685,7 +694,7 @@ class RegistrationHandler(BaseHandler):
                 shadow_banned=shadow_banned,
             )
         else:
-            return self.store.register_user(
+            await self.store.register_user(
                 user_id=user_id,
                 password_hash=password_hash,
                 was_guest=was_guest,
@@ -698,22 +707,24 @@ class RegistrationHandler(BaseHandler):
             )
 
     async def register_device(
-        self, user_id, device_id, initial_display_name, is_guest=False
-    ):
+        self,
+        user_id: str,
+        device_id: Optional[str],
+        initial_display_name: Optional[str],
+        is_guest: bool = False,
+    ) -> Tuple[str, str]:
         """Register a device for a user and generate an access token.
 
         The access token will be limited by the homeserver's session_lifetime config.
 
         Args:
-            user_id (str): full canonical @user:id
-            device_id (str|None): The device ID to check, or None to generate
-                a new one.
-            initial_display_name (str|None): An optional display name for the
-                device.
-            is_guest (bool): Whether this is a guest account
+            user_id: full canonical @user:id
+            device_id: The device ID to check, or None to generate a new one.
+            initial_display_name: An optional display name for the device.
+            is_guest: Whether this is a guest account
 
         Returns:
-            tuple[str, str]: Tuple of device ID and access token
+            Tuple of device ID and access token
         """
 
         if self.hs.config.worker_app:
@@ -733,7 +744,7 @@ class RegistrationHandler(BaseHandler):
                 )
             valid_until_ms = self.clock.time_msec() + self.session_lifetime
 
-        device_id = await self.device_handler.check_device_registered(
+        registered_device_id = await self.device_handler.check_device_registered(
             user_id, device_id, initial_display_name
         )
         if is_guest:
@@ -743,20 +754,21 @@ class RegistrationHandler(BaseHandler):
             )
         else:
             access_token = await self._auth_handler.get_access_token_for_user_id(
-                user_id, device_id=device_id, valid_until_ms=valid_until_ms
+                user_id, device_id=registered_device_id, valid_until_ms=valid_until_ms
             )
 
-        return (device_id, access_token)
+        return (registered_device_id, access_token)
 
-    async def post_registration_actions(self, user_id, auth_result, access_token):
+    async def post_registration_actions(
+        self, user_id: str, auth_result: dict, access_token: Optional[str]
+    ) -> None:
         """A user has completed registration
 
         Args:
-            user_id (str): The user ID that consented
-            auth_result (dict): The authenticated credentials of the newly
-                registered user.
-            access_token (str|None): The access token of the newly logged in
-                device, or None if `inhibit_login` enabled.
+            user_id: The user ID that consented
+            auth_result: The authenticated credentials of the newly registered user.
+            access_token: The access token of the newly logged in device, or
+                None if `inhibit_login` enabled.
         """
         if self.hs.config.worker_app:
             await self._post_registration_client(
@@ -808,19 +820,20 @@ class RegistrationHandler(BaseHandler):
         if auth_result and LoginType.TERMS in auth_result:
             await self._on_user_consented(user_id, self.hs.config.user_consent_version)
 
-    async def _on_user_consented(self, user_id, consent_version):
+    async def _on_user_consented(self, user_id: str, consent_version: str) -> None:
         """A user consented to the terms on registration
 
         Args:
-            user_id (str): The user ID that consented.
-            consent_version (str): version of the policy the user has
-                consented to.
+            user_id: The user ID that consented.
+            consent_version: version of the policy the user has consented to.
         """
         logger.info("%s has consented to the privacy policy", user_id)
         await self.store.user_set_consent_version(user_id, consent_version)
         await self.post_consent_actions(user_id)
 
-    async def register_email_threepid(self, user_id, threepid, token):
+    async def register_email_threepid(
+        self, user_id: str, threepid: dict, token: Optional[str]
+    ) -> None:
         """Add an email address as a 3pid identifier
 
         Also adds an email pusher for the email address, if configured in the
@@ -829,10 +842,9 @@ class RegistrationHandler(BaseHandler):
         Must be called on master.
 
         Args:
-            user_id (str): id of user
-            threepid (object): m.login.email.identity auth response
-            token (str|None): access_token for the user, or None if not logged
-                in.
+            user_id: id of user
+            threepid: m.login.email.identity auth response
+            token: access_token for the user, or None if not logged in.
         """
         reqd = ("medium", "address", "validated_at")
         if any(x not in threepid for x in reqd):
@@ -858,7 +870,9 @@ class RegistrationHandler(BaseHandler):
             # up when the access token is saved, but that's quite an
             # invasive change I'd rather do separately.
             user_tuple = await self.store.get_user_by_access_token(token)
-            token_id = user_tuple["token_id"]
+            # The token better still exist.
+            assert user_tuple
+            token_id = user_tuple.token_id
 
             await self.pusher_pool.add_pusher(
                 user_id=user_id,
@@ -872,14 +886,14 @@ class RegistrationHandler(BaseHandler):
                 data={},
             )
 
-    async def _register_msisdn_threepid(self, user_id, threepid):
+    async def _register_msisdn_threepid(self, user_id: str, threepid: dict) -> None:
         """Add a phone number as a 3pid identifier
 
         Must be called on master.
 
         Args:
-            user_id (str): id of user
-            threepid (object): m.login.msisdn auth response
+            user_id: id of user
+            threepid: m.login.msisdn auth response
         """
         try:
             assert_params_in_dict(threepid, ["medium", "address", "validated_at"])
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 1333999782..469f6cf10f 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -120,7 +120,7 @@ class RoomCreationHandler(BaseHandler):
         # subsequent requests
         self._upgrade_response_cache = ResponseCache(
             hs, "room_upgrade", timeout_ms=FIVE_MINUTES_IN_MS
-        )
+        )  # type: ResponseCache[Tuple[str, str]]
         self._server_notices_mxid = hs.config.server_notices_mxid
 
         self.third_party_event_rules = hs.get_third_party_event_rules()
@@ -185,6 +185,7 @@ class RoomCreationHandler(BaseHandler):
             ShadowBanError if the requester is shadow-banned.
         """
         user_id = requester.user.to_string()
+        assert self.hs.is_mine_id(user_id), "User must be our own: %s" % (user_id,)
 
         # start by allocating a new room id
         r = await self.store.get_room(old_room_id)
@@ -213,7 +214,6 @@ class RoomCreationHandler(BaseHandler):
                     "replacement_room": new_room_id,
                 },
             },
-            token_id=requester.access_token_id,
         )
         old_room_version = await self.store.get_room_version_id(old_room_id)
         await self.auth.check_from_context(
@@ -229,8 +229,8 @@ class RoomCreationHandler(BaseHandler):
         )
 
         # now send the tombstone
-        await self.event_creation_handler.send_nonmember_event(
-            requester, tombstone_event, tombstone_context
+        await self.event_creation_handler.handle_new_client_event(
+            requester=requester, event=tombstone_event, context=tombstone_context,
         )
 
         old_room_state = await tombstone_context.get_current_state_ids()
@@ -599,7 +599,7 @@ class RoomCreationHandler(BaseHandler):
         """
         user_id = requester.user.to_string()
 
-        await self.auth.check_auth_blocking(user_id)
+        await self.auth.check_auth_blocking(requester=requester)
 
         if (
             self._server_notices_mxid is not None
@@ -708,7 +708,7 @@ class RoomCreationHandler(BaseHandler):
         if not allowed_by_third_party_rules:
             raise SynapseError(403, "Room visibility value not allowed.")
 
-        directory_handler = self.hs.get_handlers().directory_handler
+        directory_handler = self.hs.get_directory_handler()
         if room_alias:
             await directory_handler.create_association(
                 requester=requester,
@@ -789,23 +789,30 @@ class RoomCreationHandler(BaseHandler):
                 ratelimit=False,
             )
 
-        for invitee in invite_list:
+        # we avoid dropping the lock between invites, as otherwise joins can
+        # start coming in and making the createRoom slow.
+        #
+        # we also don't need to check the requester's shadow-ban here, as we
+        # have already done so above (and potentially emptied invite_list).
+        with (await self.room_member_handler.member_linearizer.queue((room_id,))):
             content = {}
             is_direct = config.get("is_direct", None)
             if is_direct:
                 content["is_direct"] = is_direct
 
-            # Note that update_membership with an action of "invite" can raise a
-            # ShadowBanError, but this was handled above by emptying invite_list.
-            _, last_stream_id = await self.room_member_handler.update_membership(
-                requester,
-                UserID.from_string(invitee),
-                room_id,
-                "invite",
-                ratelimit=False,
-                content=content,
-                new_room=True,
-            )
+            for invitee in invite_list:
+                (
+                    _,
+                    last_stream_id,
+                ) = await self.room_member_handler.update_membership_locked(
+                    requester,
+                    UserID.from_string(invitee),
+                    room_id,
+                    "invite",
+                    ratelimit=False,
+                    content=content,
+                    new_room=True,
+                )
 
         for invite_3pid in invite_3pid_list:
             id_server = invite_3pid["id_server"]
@@ -992,8 +999,6 @@ class RoomCreationHandler(BaseHandler):
             try:
                 random_string = stringutils.random_string(18)
                 gen_room_id = RoomID(random_string, self.hs.hostname).to_string()
-                if isinstance(gen_room_id, bytes):
-                    gen_room_id = gen_room_id.decode("utf-8")
                 await self.store.store_room(
                     room_id=gen_room_id,
                     room_creator_user_id=creator_id,
@@ -1273,7 +1278,9 @@ class RoomShutdownHandler:
                     400, "User must be our own: %s" % (new_room_user_id,)
                 )
 
-            room_creator_requester = create_requester(new_room_user_id)
+            room_creator_requester = create_requester(
+                new_room_user_id, authenticated_entity=requester_user_id
+            )
 
             info, stream_id = await self._room_creation_handler.create_room(
                 room_creator_requester,
@@ -1291,7 +1298,7 @@ class RoomShutdownHandler:
             )
 
             # We now wait for the create room to come back in via replication so
-            # that we can assume that all the joins/invites have propogated before
+            # that we can assume that all the joins/invites have propagated before
             # we try and auto join below.
             await self._replication.wait_for_stream_position(
                 self.hs.config.worker.events_shard_config.get_instance(new_room_id),
@@ -1313,7 +1320,9 @@ class RoomShutdownHandler:
 
             try:
                 # Kick users from room
-                target_requester = create_requester(user_id)
+                target_requester = create_requester(
+                    user_id, authenticated_entity=requester_user_id
+                )
                 _, stream_id = await self.room_member_handler.update_membership(
                     requester=target_requester,
                     target=target_requester.user,
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 6af59b3f70..9b15dd9951 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -17,12 +17,10 @@ import abc
 import logging
 import random
 from http import HTTPStatus
-from typing import TYPE_CHECKING, Iterable, List, Optional, Tuple, Union
-
-from unpaddedbase64 import encode_base64
+from typing import TYPE_CHECKING, Iterable, List, Optional, Tuple
 
 from synapse import types
-from synapse.api.constants import MAX_DEPTH, EventTypes, Membership
+from synapse.api.constants import AccountDataTypes, EventTypes, Membership
 from synapse.api.errors import (
     AuthError,
     Codes,
@@ -31,13 +29,8 @@ from synapse.api.errors import (
     SynapseError,
 )
 from synapse.api.ratelimiting import Ratelimiter
-from synapse.api.room_versions import EventFormatVersions
-from synapse.crypto.event_signing import compute_event_reference_hash
 from synapse.events import EventBase
-from synapse.events.builder import create_local_event_from_event_dict
 from synapse.events.snapshot import EventContext
-from synapse.events.validator import EventValidator
-from synapse.storage.roommember import RoomsForUser
 from synapse.types import JsonDict, Requester, RoomAlias, RoomID, StateMap, UserID
 from synapse.util.async_helpers import Linearizer
 from synapse.util.distributor import user_left_room
@@ -64,13 +57,12 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         self.state_handler = hs.get_state_handler()
         self.config = hs.config
 
-        self.federation_handler = hs.get_handlers().federation_handler
-        self.directory_handler = hs.get_handlers().directory_handler
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.federation_handler = hs.get_federation_handler()
+        self.directory_handler = hs.get_directory_handler()
+        self.identity_handler = hs.get_identity_handler()
         self.registration_handler = hs.get_registration_handler()
         self.profile_handler = hs.get_profile_handler()
         self.event_creation_handler = hs.get_event_creation_handler()
-        self.identity_handler = hs.get_handlers().identity_handler
 
         self.member_linearizer = Linearizer(name="member")
 
@@ -172,6 +164,17 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         if requester.is_guest:
             content["kind"] = "guest"
 
+        # Check if we already have an event with a matching transaction ID. (We
+        # do this check just before we persist an event as well, but may as well
+        # do it up front for efficiency.)
+        if txn_id and requester.access_token_id:
+            existing_event_id = await self.store.get_event_id_from_transaction_id(
+                room_id, requester.user.to_string(), requester.access_token_id, txn_id,
+            )
+            if existing_event_id:
+                event_pos = await self.store.get_position_for_event(existing_event_id)
+                return existing_event_id, event_pos.stream
+
         event, context = await self.event_creation_handler.create_event(
             requester,
             {
@@ -183,21 +186,11 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
                 # For backwards compatibility:
                 "membership": membership,
             },
-            token_id=requester.access_token_id,
             txn_id=txn_id,
             prev_event_ids=prev_event_ids,
             require_consent=require_consent,
         )
 
-        # Check if this event matches the previous membership event for the user.
-        duplicate = await self.event_creation_handler.deduplicate_state_event(
-            event, context
-        )
-        if duplicate is not None:
-            # Discard the new event since this membership change is a no-op.
-            _, stream_id = await self.store.get_event_ordering(duplicate.event_id)
-            return duplicate.event_id, stream_id
-
         prev_state_ids = await context.get_prev_state_ids()
 
         prev_member_event_id = prev_state_ids.get((EventTypes.Member, user_id), None)
@@ -222,7 +215,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
                         retry_after_ms=int(1000 * (time_allowed - time_now_s))
                     )
 
-        stream_id = await self.event_creation_handler.handle_new_client_event(
+        result_event = await self.event_creation_handler.handle_new_client_event(
             requester, event, context, extra_users=[target], ratelimit=ratelimit,
         )
 
@@ -232,7 +225,9 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
                 if prev_member_event.membership == Membership.JOIN:
                     await self._user_left_room(target, room_id)
 
-        return event.event_id, stream_id
+        # we know it was persisted, so should have a stream ordering
+        assert result_event.internal_metadata.stream_ordering
+        return result_event.event_id, result_event.internal_metadata.stream_ordering
 
     async def copy_room_tags_and_direct_to_room(
         self, old_room_id, new_room_id, user_id
@@ -248,7 +243,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         user_account_data, _ = await self.store.get_account_data_for_user(user_id)
 
         # Copy direct message state if applicable
-        direct_rooms = user_account_data.get("m.direct", {})
+        direct_rooms = user_account_data.get(AccountDataTypes.DIRECT, {})
 
         # Check which key this room is under
         if isinstance(direct_rooms, dict):
@@ -259,7 +254,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
 
                     # Save back to user's m.direct account data
                     await self.store.add_account_data_for_user(
-                        user_id, "m.direct", direct_rooms
+                        user_id, AccountDataTypes.DIRECT, direct_rooms
                     )
                     break
 
@@ -312,7 +307,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         key = (room_id,)
 
         with (await self.member_linearizer.queue(key)):
-            result = await self._update_membership(
+            result = await self.update_membership_locked(
                 requester,
                 target,
                 room_id,
@@ -328,7 +323,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
 
         return result
 
-    async def _update_membership(
+    async def update_membership_locked(
         self,
         requester: Requester,
         target: UserID,
@@ -342,6 +337,10 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         new_room: bool = False,
         require_consent: bool = True,
     ) -> Tuple[str, int]:
+        """Helper for update_membership.
+
+        Assumes that the membership linearizer is already held for the room.
+        """
         content_specified = bool(content)
         if content is None:
             content = {}
@@ -460,12 +459,12 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
                 same_membership = old_membership == effective_membership_state
                 same_sender = requester.user.to_string() == old_state.sender
                 if same_sender and same_membership and same_content:
-                    _, stream_id = await self.store.get_event_ordering(
-                        old_state.event_id
-                    )
+                    # duplicate event.
+                    # we know it was persisted, so must have a stream ordering.
+                    assert old_state.internal_metadata.stream_ordering
                     return (
                         old_state.event_id,
-                        stream_id,
+                        old_state.internal_metadata.stream_ordering,
                     )
 
             if old_membership in ["ban", "leave"] and action == "kick":
@@ -552,10 +551,16 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         elif effective_membership_state == Membership.LEAVE:
             if not is_host_in_room:
                 # perhaps we've been invited
-                invite = await self.store.get_invite_for_local_user_in_room(
-                    user_id=target.to_string(), room_id=room_id
-                )  # type: Optional[RoomsForUser]
-                if not invite:
+                (
+                    current_membership_type,
+                    current_membership_event_id,
+                ) = await self.store.get_local_current_membership_for_user_in_room(
+                    target.to_string(), room_id
+                )
+                if (
+                    current_membership_type != Membership.INVITE
+                    or not current_membership_event_id
+                ):
                     logger.info(
                         "%s sent a leave request to %s, but that is not an active room "
                         "on this server, and there is no pending invite",
@@ -565,6 +570,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
 
                     raise SynapseError(404, "Not a known room")
 
+                invite = await self.store.get_event(current_membership_event_id)
                 logger.info(
                     "%s rejects invite to %s from %s", target, room_id, invite.sender
                 )
@@ -680,7 +686,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
 
     async def send_membership_event(
         self,
-        requester: Requester,
+        requester: Optional[Requester],
         event: EventBase,
         context: EventContext,
         ratelimit: bool = True,
@@ -710,12 +716,6 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
         else:
             requester = types.create_requester(target_user)
 
-        prev_event = await self.event_creation_handler.deduplicate_state_event(
-            event, context
-        )
-        if prev_event is not None:
-            return
-
         prev_state_ids = await context.get_prev_state_ids()
         if event.membership == Membership.JOIN:
             if requester.is_guest:
@@ -730,7 +730,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
             if is_blocked:
                 raise SynapseError(403, "This room has been blocked on this server")
 
-        await self.event_creation_handler.handle_new_client_event(
+        event = await self.event_creation_handler.handle_new_client_event(
             requester, event, context, extra_users=[target_user], ratelimit=ratelimit
         )
 
@@ -1032,6 +1032,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):
 
         self.distributor = hs.get_distributor()
         self.distributor.declare("user_left_room")
+        self._server_name = hs.hostname
 
     async def _is_remote_room_too_complex(
         self, room_id: str, remote_room_hosts: List[str]
@@ -1126,7 +1127,9 @@ class RoomMemberMasterHandler(RoomMemberHandler):
                 return event_id, stream_id
 
             # The room is too large. Leave.
-            requester = types.create_requester(user, None, False, False, None)
+            requester = types.create_requester(
+                user, authenticated_entity=self._server_name
+            )
             await self.update_membership(
                 requester=requester, target=user, room_id=room_id, action="leave"
             )
@@ -1171,57 +1174,38 @@ class RoomMemberMasterHandler(RoomMemberHandler):
             #
             logger.warning("Failed to reject invite: %s", e)
 
-            return await self._locally_reject_invite(
+            return await self._generate_local_out_of_band_leave(
                 invite_event, txn_id, requester, content
             )
 
-    async def _locally_reject_invite(
+    async def _generate_local_out_of_band_leave(
         self,
-        invite_event: EventBase,
+        previous_membership_event: EventBase,
         txn_id: Optional[str],
         requester: Requester,
         content: JsonDict,
     ) -> Tuple[str, int]:
-        """Generate a local invite rejection
+        """Generate a local leave event for a room
 
-        This is called after we fail to reject an invite via a remote server. It
-        generates an out-of-band membership event locally.
+        This can be called after we e.g fail to reject an invite via a remote server.
+        It generates an out-of-band membership event locally.
 
         Args:
-            invite_event: the invite to be rejected
+            previous_membership_event: the previous membership event for this user
             txn_id: optional transaction ID supplied by the client
-            requester:  user making the rejection request, according to the access token
-            content: additional content to include in the rejection event.
+            requester: user making the request, according to the access token
+            content: additional content to include in the leave event.
                Normally an empty dict.
-        """
 
-        room_id = invite_event.room_id
-        target_user = invite_event.state_key
-        room_version = await self.store.get_room_version(room_id)
+        Returns:
+            A tuple containing (event_id, stream_id of the leave event)
+        """
+        room_id = previous_membership_event.room_id
+        target_user = previous_membership_event.state_key
 
         content["membership"] = Membership.LEAVE
 
-        # the auth events for the new event are the same as that of the invite, plus
-        # the invite itself.
-        #
-        # the prev_events are just the invite.
-        invite_hash = invite_event.event_id  # type: Union[str, Tuple]
-        if room_version.event_format == EventFormatVersions.V1:
-            alg, h = compute_event_reference_hash(invite_event)
-            invite_hash = (invite_event.event_id, {alg: encode_base64(h)})
-
-        auth_events = tuple(invite_event.auth_events) + (invite_hash,)
-        prev_events = (invite_hash,)
-
-        # we cap depth of generated events, to ensure that they are not
-        # rejected by other servers (and so that they can be persisted in
-        # the db)
-        depth = min(invite_event.depth + 1, MAX_DEPTH)
-
         event_dict = {
-            "depth": depth,
-            "auth_events": auth_events,
-            "prev_events": prev_events,
             "type": EventTypes.Member,
             "room_id": room_id,
             "sender": target_user,
@@ -1229,28 +1213,30 @@ class RoomMemberMasterHandler(RoomMemberHandler):
             "state_key": target_user,
         }
 
-        event = create_local_event_from_event_dict(
-            clock=self.clock,
-            hostname=self.hs.hostname,
-            signing_key=self.hs.signing_key,
-            room_version=room_version,
-            event_dict=event_dict,
+        # the auth events for the new event are the same as that of the previous event, plus
+        # the event itself.
+        #
+        # the prev_events consist solely of the previous membership event.
+        prev_event_ids = [previous_membership_event.event_id]
+        auth_event_ids = previous_membership_event.auth_event_ids() + prev_event_ids
+
+        event, context = await self.event_creation_handler.create_event(
+            requester,
+            event_dict,
+            txn_id=txn_id,
+            prev_event_ids=prev_event_ids,
+            auth_event_ids=auth_event_ids,
         )
         event.internal_metadata.outlier = True
         event.internal_metadata.out_of_band_membership = True
-        if txn_id is not None:
-            event.internal_metadata.txn_id = txn_id
-        if requester.access_token_id is not None:
-            event.internal_metadata.token_id = requester.access_token_id
 
-        EventValidator().validate_new(event, self.config)
-
-        context = await self.state_handler.compute_event_context(event)
-        context.app_service = requester.app_service
-        stream_id = await self.event_creation_handler.handle_new_client_event(
+        result_event = await self.event_creation_handler.handle_new_client_event(
             requester, event, context, extra_users=[UserID.from_string(target_user)],
         )
-        return event.event_id, stream_id
+        # we know it was persisted, so must have a stream ordering
+        assert result_event.internal_metadata.stream_ordering
+
+        return result_event.event_id, result_event.internal_metadata.stream_ordering
 
     async def _user_left_room(self, target: UserID, room_id: str) -> None:
         """Implements RoomMemberHandler._user_left_room
diff --git a/synapse/handlers/saml_handler.py b/synapse/handlers/saml_handler.py
index 285c481a96..76d4169fe2 100644
--- a/synapse/handlers/saml_handler.py
+++ b/synapse/handlers/saml_handler.py
@@ -24,7 +24,8 @@ from saml2.client import Saml2Client
 from synapse.api.errors import SynapseError
 from synapse.config import ConfigError
 from synapse.config.saml2_config import SamlAttributeRequirement
-from synapse.http.server import respond_with_html
+from synapse.handlers._base import BaseHandler
+from synapse.handlers.sso import MappingException, UserAttributes
 from synapse.http.servlet import parse_string
 from synapse.http.site import SynapseRequest
 from synapse.module_api import ModuleApi
@@ -37,15 +38,11 @@ from synapse.util.async_helpers import Linearizer
 from synapse.util.iterutils import chunk_seq
 
 if TYPE_CHECKING:
-    import synapse.server
+    from synapse.server import HomeServer
 
 logger = logging.getLogger(__name__)
 
 
-class MappingException(Exception):
-    """Used to catch errors when mapping the SAML2 response to a user."""
-
-
 @attr.s(slots=True)
 class Saml2SessionData:
     """Data we track about SAML2 sessions"""
@@ -57,17 +54,14 @@ class Saml2SessionData:
     ui_auth_session_id = attr.ib(type=Optional[str], default=None)
 
 
-class SamlHandler:
-    def __init__(self, hs: "synapse.server.HomeServer"):
-        self.hs = hs
+class SamlHandler(BaseHandler):
+    def __init__(self, hs: "HomeServer"):
+        super().__init__(hs)
         self._saml_client = Saml2Client(hs.config.saml2_sp_config)
-        self._auth = hs.get_auth()
+        self._saml_idp_entityid = hs.config.saml2_idp_entityid
         self._auth_handler = hs.get_auth_handler()
         self._registration_handler = hs.get_registration_handler()
 
-        self._clock = hs.get_clock()
-        self._datastore = hs.get_datastore()
-        self._hostname = hs.hostname
         self._saml2_session_lifetime = hs.config.saml2_session_lifetime
         self._grandfathered_mxid_source_attribute = (
             hs.config.saml2_grandfathered_mxid_source_attribute
@@ -88,26 +82,9 @@ class SamlHandler:
         self._outstanding_requests_dict = {}  # type: Dict[str, Saml2SessionData]
 
         # a lock on the mappings
-        self._mapping_lock = Linearizer(name="saml_mapping", clock=self._clock)
+        self._mapping_lock = Linearizer(name="saml_mapping", clock=self.clock)
 
-    def _render_error(
-        self, request, error: str, error_description: Optional[str] = None
-    ) -> None:
-        """Render the error template and respond to the request with it.
-
-        This is used to show errors to the user. The template of this page can
-        be found under `synapse/res/templates/sso_error.html`.
-
-        Args:
-            request: The incoming request from the browser.
-                We'll respond with an HTML page describing the error.
-            error: A technical identifier for this error.
-            error_description: A human-readable description of the error.
-        """
-        html = self._error_template.render(
-            error=error, error_description=error_description
-        )
-        respond_with_html(request, 400, html)
+        self._sso_handler = hs.get_sso_handler()
 
     def handle_redirect_request(
         self, client_redirect_url: bytes, ui_auth_session_id: Optional[str] = None
@@ -124,13 +101,13 @@ class SamlHandler:
             URL to redirect to
         """
         reqid, info = self._saml_client.prepare_for_authenticate(
-            relay_state=client_redirect_url
+            entityid=self._saml_idp_entityid, relay_state=client_redirect_url
         )
 
         # Since SAML sessions timeout it is useful to log when they were created.
         logger.info("Initiating a new SAML session: %s" % (reqid,))
 
-        now = self._clock.time_msec()
+        now = self.clock.time_msec()
         self._outstanding_requests_dict[reqid] = Saml2SessionData(
             creation_time=now, ui_auth_session_id=ui_auth_session_id,
         )
@@ -171,12 +148,12 @@ class SamlHandler:
             # in the (user-visible) exception message, so let's log the exception here
             # so we can track down the session IDs later.
             logger.warning(str(e))
-            self._render_error(
+            self._sso_handler.render_error(
                 request, "unsolicited_response", "Unexpected SAML2 login."
             )
             return
         except Exception as e:
-            self._render_error(
+            self._sso_handler.render_error(
                 request,
                 "invalid_response",
                 "Unable to parse SAML2 response: %s." % (e,),
@@ -184,7 +161,7 @@ class SamlHandler:
             return
 
         if saml2_auth.not_signed:
-            self._render_error(
+            self._sso_handler.render_error(
                 request, "unsigned_respond", "SAML2 response was not signed."
             )
             return
@@ -210,15 +187,13 @@ class SamlHandler:
         # attributes.
         for requirement in self._saml2_attribute_requirements:
             if not _check_attribute_requirement(saml2_auth.ava, requirement):
-                self._render_error(
+                self._sso_handler.render_error(
                     request, "unauthorised", "You are not authorised to log in here."
                 )
                 return
 
         # Pull out the user-agent and IP from the request.
-        user_agent = request.requestHeaders.getRawHeaders(b"User-Agent", default=[b""])[
-            0
-        ].decode("ascii", "surrogateescape")
+        user_agent = request.get_user_agent("")
         ip_address = self.hs.get_ip_from_request(request)
 
         # Call the mapper to register/login the user
@@ -228,7 +203,7 @@ class SamlHandler:
             )
         except MappingException as e:
             logger.exception("Could not map user")
-            self._render_error(request, "mapping_error", str(e))
+            self._sso_handler.render_error(request, "mapping_error", str(e))
             return
 
         # Complete the interactive auth session or the login.
@@ -274,20 +249,26 @@ class SamlHandler:
                 "Failed to extract remote user id from SAML response"
             )
 
-        with (await self._mapping_lock.queue(self._auth_provider_id)):
-            # first of all, check if we already have a mapping for this user
-            logger.info(
-                "Looking for existing mapping for user %s:%s",
-                self._auth_provider_id,
-                remote_user_id,
-            )
-            registered_user_id = await self._datastore.get_user_by_external_id(
-                self._auth_provider_id, remote_user_id
-            )
-            if registered_user_id is not None:
-                logger.info("Found existing mapping %s", registered_user_id)
-                return registered_user_id
+        async def saml_response_to_remapped_user_attributes(
+            failures: int,
+        ) -> UserAttributes:
+            """
+            Call the mapping provider to map a SAML response to user attributes and coerce the result into the standard form.
 
+            This is backwards compatibility for abstraction for the SSO handler.
+            """
+            # Call the mapping provider.
+            result = self._user_mapping_provider.saml_response_to_user_attributes(
+                saml2_auth, failures, client_redirect_url
+            )
+            # Remap some of the results.
+            return UserAttributes(
+                localpart=result.get("mxid_localpart"),
+                display_name=result.get("displayname"),
+                emails=result.get("emails", []),
+            )
+
+        async def grandfather_existing_users() -> Optional[str]:
             # backwards-compatibility hack: see if there is an existing user with a
             # suitable mapping from the uid
             if (
@@ -296,75 +277,35 @@ class SamlHandler:
             ):
                 attrval = saml2_auth.ava[self._grandfathered_mxid_source_attribute][0]
                 user_id = UserID(
-                    map_username_to_mxid_localpart(attrval), self._hostname
+                    map_username_to_mxid_localpart(attrval), self.server_name
                 ).to_string()
-                logger.info(
+
+                logger.debug(
                     "Looking for existing account based on mapped %s %s",
                     self._grandfathered_mxid_source_attribute,
                     user_id,
                 )
 
-                users = await self._datastore.get_users_by_id_case_insensitive(user_id)
+                users = await self.store.get_users_by_id_case_insensitive(user_id)
                 if users:
                     registered_user_id = list(users.keys())[0]
                     logger.info("Grandfathering mapping to %s", registered_user_id)
-                    await self._datastore.record_user_external_id(
-                        self._auth_provider_id, remote_user_id, registered_user_id
-                    )
                     return registered_user_id
 
-            # Map saml response to user attributes using the configured mapping provider
-            for i in range(1000):
-                attribute_dict = self._user_mapping_provider.saml_response_to_user_attributes(
-                    saml2_auth, i, client_redirect_url=client_redirect_url,
-                )
+            return None
 
-                logger.debug(
-                    "Retrieved SAML attributes from user mapping provider: %s "
-                    "(attempt %d)",
-                    attribute_dict,
-                    i,
-                )
-
-                localpart = attribute_dict.get("mxid_localpart")
-                if not localpart:
-                    raise MappingException(
-                        "Error parsing SAML2 response: SAML mapping provider plugin "
-                        "did not return a mxid_localpart value"
-                    )
-
-                displayname = attribute_dict.get("displayname")
-                emails = attribute_dict.get("emails", [])
-
-                # Check if this mxid already exists
-                if not await self._datastore.get_users_by_id_case_insensitive(
-                    UserID(localpart, self._hostname).to_string()
-                ):
-                    # This mxid is free
-                    break
-            else:
-                # Unable to generate a username in 1000 iterations
-                # Break and return error to the user
-                raise MappingException(
-                    "Unable to generate a Matrix ID from the SAML response"
-                )
-
-            logger.info("Mapped SAML user to local part %s", localpart)
-
-            registered_user_id = await self._registration_handler.register_user(
-                localpart=localpart,
-                default_display_name=displayname,
-                bind_emails=emails,
-                user_agent_ips=(user_agent, ip_address),
+        with (await self._mapping_lock.queue(self._auth_provider_id)):
+            return await self._sso_handler.get_mxid_from_sso(
+                self._auth_provider_id,
+                remote_user_id,
+                user_agent,
+                ip_address,
+                saml_response_to_remapped_user_attributes,
+                grandfather_existing_users,
             )
 
-            await self._datastore.record_user_external_id(
-                self._auth_provider_id, remote_user_id, registered_user_id
-            )
-            return registered_user_id
-
     def expire_sessions(self):
-        expire_before = self._clock.time_msec() - self._saml2_session_lifetime
+        expire_before = self.clock.time_msec() - self._saml2_session_lifetime
         to_expire = set()
         for reqid, data in self._outstanding_requests_dict.items():
             if data.creation_time < expire_before:
@@ -476,11 +417,11 @@ class DefaultSamlMappingProvider:
             )
 
         # Use the configured mapper for this mxid_source
-        base_mxid_localpart = self._mxid_mapper(mxid_source)
+        localpart = self._mxid_mapper(mxid_source)
 
         # Append suffix integer if last call to this function failed to produce
-        # a usable mxid
-        localpart = base_mxid_localpart + (str(failures) if failures else "")
+        # a usable mxid.
+        localpart += str(failures) if failures else ""
 
         # Retrieve the display name from the saml response
         # If displayname is None, the mxid_localpart will be used instead
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index e9402e6e2e..66f1bbcfc4 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -139,7 +139,7 @@ class SearchHandler(BaseHandler):
             # Filter to apply to results
             filter_dict = room_cat.get("filter", {})
 
-            # What to order results by (impacts whether pagination can be doen)
+            # What to order results by (impacts whether pagination can be done)
             order_by = room_cat.get("order_by", "rank")
 
             # Return the current state of the rooms?
diff --git a/synapse/handlers/sso.py b/synapse/handlers/sso.py
new file mode 100644
index 0000000000..47ad96f97e
--- /dev/null
+++ b/synapse/handlers/sso.py
@@ -0,0 +1,244 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+from typing import TYPE_CHECKING, Awaitable, Callable, List, Optional
+
+import attr
+
+from synapse.api.errors import RedirectException
+from synapse.handlers._base import BaseHandler
+from synapse.http.server import respond_with_html
+from synapse.types import UserID, contains_invalid_mxid_characters
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
+logger = logging.getLogger(__name__)
+
+
+class MappingException(Exception):
+    """Used to catch errors when mapping an SSO response to user attributes.
+
+    Note that the msg that is raised is shown to end-users.
+    """
+
+
+@attr.s
+class UserAttributes:
+    localpart = attr.ib(type=str)
+    display_name = attr.ib(type=Optional[str], default=None)
+    emails = attr.ib(type=List[str], default=attr.Factory(list))
+
+
+class SsoHandler(BaseHandler):
+    # The number of attempts to ask the mapping provider for when generating an MXID.
+    _MAP_USERNAME_RETRIES = 1000
+
+    def __init__(self, hs: "HomeServer"):
+        super().__init__(hs)
+        self._registration_handler = hs.get_registration_handler()
+        self._error_template = hs.config.sso_error_template
+
+    def render_error(
+        self, request, error: str, error_description: Optional[str] = None
+    ) -> None:
+        """Renders the error template and responds with it.
+
+        This is used to show errors to the user. The template of this page can
+        be found under `synapse/res/templates/sso_error.html`.
+
+        Args:
+            request: The incoming request from the browser.
+                We'll respond with an HTML page describing the error.
+            error: A technical identifier for this error.
+            error_description: A human-readable description of the error.
+        """
+        html = self._error_template.render(
+            error=error, error_description=error_description
+        )
+        respond_with_html(request, 400, html)
+
+    async def get_sso_user_by_remote_user_id(
+        self, auth_provider_id: str, remote_user_id: str
+    ) -> Optional[str]:
+        """
+        Maps the user ID of a remote IdP to a mxid for a previously seen user.
+
+        If the user has not been seen yet, this will return None.
+
+        Args:
+            auth_provider_id: A unique identifier for this SSO provider, e.g.
+                "oidc" or "saml".
+            remote_user_id: The user ID according to the remote IdP. This might
+                be an e-mail address, a GUID, or some other form. It must be
+                unique and immutable.
+
+        Returns:
+            The mxid of a previously seen user.
+        """
+        logger.debug(
+            "Looking for existing mapping for user %s:%s",
+            auth_provider_id,
+            remote_user_id,
+        )
+
+        # Check if we already have a mapping for this user.
+        previously_registered_user_id = await self.store.get_user_by_external_id(
+            auth_provider_id, remote_user_id,
+        )
+
+        # A match was found, return the user ID.
+        if previously_registered_user_id is not None:
+            logger.info(
+                "Found existing mapping for IdP '%s' and remote_user_id '%s': %s",
+                auth_provider_id,
+                remote_user_id,
+                previously_registered_user_id,
+            )
+            return previously_registered_user_id
+
+        # No match.
+        return None
+
+    async def get_mxid_from_sso(
+        self,
+        auth_provider_id: str,
+        remote_user_id: str,
+        user_agent: str,
+        ip_address: str,
+        sso_to_matrix_id_mapper: Callable[[int], Awaitable[UserAttributes]],
+        grandfather_existing_users: Optional[Callable[[], Awaitable[Optional[str]]]],
+    ) -> str:
+        """
+        Given an SSO ID, retrieve the user ID for it and possibly register the user.
+
+        This first checks if the SSO ID has previously been linked to a matrix ID,
+        if it has that matrix ID is returned regardless of the current mapping
+        logic.
+
+        If a callable is provided for grandfathering users, it is called and can
+        potentially return a matrix ID to use. If it does, the SSO ID is linked to
+        this matrix ID for subsequent calls.
+
+        The mapping function is called (potentially multiple times) to generate
+        a localpart for the user.
+
+        If an unused localpart is generated, the user is registered from the
+        given user-agent and IP address and the SSO ID is linked to this matrix
+        ID for subsequent calls.
+
+        Args:
+            auth_provider_id: A unique identifier for this SSO provider, e.g.
+                "oidc" or "saml".
+            remote_user_id: The unique identifier from the SSO provider.
+            user_agent: The user agent of the client making the request.
+            ip_address: The IP address of the client making the request.
+            sso_to_matrix_id_mapper: A callable to generate the user attributes.
+                The only parameter is an integer which represents the amount of
+                times the returned mxid localpart mapping has failed.
+
+                It is expected that the mapper can raise two exceptions, which
+                will get passed through to the caller:
+
+                    MappingException if there was a problem mapping the response
+                        to the user.
+                    RedirectException to redirect to an additional page (e.g.
+                        to prompt the user for more information).
+            grandfather_existing_users: A callable which can return an previously
+                existing matrix ID. The SSO ID is then linked to the returned
+                matrix ID.
+
+        Returns:
+             The user ID associated with the SSO response.
+
+        Raises:
+            MappingException if there was a problem mapping the response to a user.
+            RedirectException: if the mapping provider needs to redirect the user
+                to an additional page. (e.g. to prompt for more information)
+
+        """
+        # first of all, check if we already have a mapping for this user
+        previously_registered_user_id = await self.get_sso_user_by_remote_user_id(
+            auth_provider_id, remote_user_id,
+        )
+        if previously_registered_user_id:
+            return previously_registered_user_id
+
+        # Check for grandfathering of users.
+        if grandfather_existing_users:
+            previously_registered_user_id = await grandfather_existing_users()
+            if previously_registered_user_id:
+                # Future logins should also match this user ID.
+                await self.store.record_user_external_id(
+                    auth_provider_id, remote_user_id, previously_registered_user_id
+                )
+                return previously_registered_user_id
+
+        # Otherwise, generate a new user.
+        for i in range(self._MAP_USERNAME_RETRIES):
+            try:
+                attributes = await sso_to_matrix_id_mapper(i)
+            except (RedirectException, MappingException):
+                # Mapping providers are allowed to issue a redirect (e.g. to ask
+                # the user for more information) and can issue a mapping exception
+                # if a name cannot be generated.
+                raise
+            except Exception as e:
+                # Any other exception is unexpected.
+                raise MappingException(
+                    "Could not extract user attributes from SSO response."
+                ) from e
+
+            logger.debug(
+                "Retrieved user attributes from user mapping provider: %r (attempt %d)",
+                attributes,
+                i,
+            )
+
+            if not attributes.localpart:
+                raise MappingException(
+                    "Error parsing SSO response: SSO mapping provider plugin "
+                    "did not return a localpart value"
+                )
+
+            # Check if this mxid already exists
+            user_id = UserID(attributes.localpart, self.server_name).to_string()
+            if not await self.store.get_users_by_id_case_insensitive(user_id):
+                # This mxid is free
+                break
+        else:
+            # Unable to generate a username in 1000 iterations
+            # Break and return error to the user
+            raise MappingException(
+                "Unable to generate a Matrix ID from the SSO response"
+            )
+
+        # Since the localpart is provided via a potentially untrusted module,
+        # ensure the MXID is valid before registering.
+        if contains_invalid_mxid_characters(attributes.localpart):
+            raise MappingException("localpart is invalid: %s" % (attributes.localpart,))
+
+        logger.debug("Mapped SSO user to local part %s", attributes.localpart)
+        registered_user_id = await self._registration_handler.register_user(
+            localpart=attributes.localpart,
+            default_display_name=attributes.display_name,
+            bind_emails=attributes.emails,
+            user_agent_ips=[(user_agent, ip_address)],
+        )
+
+        await self.store.record_user_external_id(
+            auth_provider_id, remote_user_id, registered_user_id
+        )
+        return registered_user_id
diff --git a/synapse/handlers/state_deltas.py b/synapse/handlers/state_deltas.py
index 7a4ae0727a..fb4f70e8e2 100644
--- a/synapse/handlers/state_deltas.py
+++ b/synapse/handlers/state_deltas.py
@@ -32,7 +32,7 @@ class StateDeltasHandler:
         Returns:
             None if the field in the events either both match `public_value`
             or if neither do, i.e. there has been no change.
-            True if it didnt match `public_value` but now does
+            True if it didn't match `public_value` but now does
             False if it did match `public_value` but now doesn't
         """
         prev_event = None
diff --git a/synapse/handlers/stats.py b/synapse/handlers/stats.py
index 249ffe2a55..dc62b21c06 100644
--- a/synapse/handlers/stats.py
+++ b/synapse/handlers/stats.py
@@ -49,7 +49,7 @@ class StatsHandler:
         # Guard to ensure we only process deltas one at a time
         self._is_processing = False
 
-        if hs.config.stats_enabled:
+        if self.stats_enabled and hs.config.run_background_tasks:
             self.notifier.add_replication_callback(self.notify_new_event)
 
             # We kick this off so that we don't have to wait for a change before
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index bfe2583002..9827c7eb8d 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -13,7 +13,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import itertools
 import logging
 from typing import TYPE_CHECKING, Any, Dict, FrozenSet, List, Optional, Set, Tuple
@@ -21,7 +20,7 @@ from typing import TYPE_CHECKING, Any, Dict, FrozenSet, List, Optional, Set, Tup
 import attr
 from prometheus_client import Counter
 
-from synapse.api.constants import EventTypes, Membership
+from synapse.api.constants import AccountDataTypes, EventTypes, Membership
 from synapse.api.filtering import FilterCollection
 from synapse.events import EventBase
 from synapse.logging.context import current_context
@@ -32,6 +31,7 @@ from synapse.types import (
     Collection,
     JsonDict,
     MutableStateMap,
+    Requester,
     RoomStreamToken,
     StateMap,
     StreamToken,
@@ -87,7 +87,7 @@ class SyncConfig:
 class TimelineBatch:
     prev_batch = attr.ib(type=StreamToken)
     events = attr.ib(type=List[EventBase])
-    limited = attr.ib(bool)
+    limited = attr.ib(type=bool)
 
     def __bool__(self) -> bool:
         """Make the result appear empty if there are no updates. This is used
@@ -201,6 +201,8 @@ class SyncResult:
         device_lists: List of user_ids whose devices have changed
         device_one_time_keys_count: Dict of algorithm to count for one time keys
             for this device
+        device_unused_fallback_key_types: List of key types that have an unused fallback
+            key
         groups: Group updates, if any
     """
 
@@ -213,6 +215,7 @@ class SyncResult:
     to_device = attr.ib(type=List[JsonDict])
     device_lists = attr.ib(type=DeviceLists)
     device_one_time_keys_count = attr.ib(type=JsonDict)
+    device_unused_fallback_key_types = attr.ib(type=List[str])
     groups = attr.ib(type=Optional[GroupsSyncResult])
 
     def __bool__(self) -> bool:
@@ -240,7 +243,9 @@ class SyncHandler:
         self.presence_handler = hs.get_presence_handler()
         self.event_sources = hs.get_event_sources()
         self.clock = hs.get_clock()
-        self.response_cache = ResponseCache(hs, "sync")
+        self.response_cache = ResponseCache(
+            hs, "sync"
+        )  # type: ResponseCache[Tuple[Any, ...]]
         self.state = hs.get_state_handler()
         self.auth = hs.get_auth()
         self.storage = hs.get_storage()
@@ -256,6 +261,7 @@ class SyncHandler:
 
     async def wait_for_sync_for_user(
         self,
+        requester: Requester,
         sync_config: SyncConfig,
         since_token: Optional[StreamToken] = None,
         timeout: int = 0,
@@ -269,7 +275,7 @@ class SyncHandler:
         # not been exceeded (if not part of the group by this point, almost certain
         # auth_blocking will occur)
         user_id = sync_config.user.to_string()
-        await self.auth.check_auth_blocking(user_id)
+        await self.auth.check_auth_blocking(requester=requester)
 
         res = await self.response_cache.wrap(
             sync_config.request_key,
@@ -457,8 +463,13 @@ class SyncHandler:
                 recents = []
 
             if not limited or block_all_timeline:
+                prev_batch_token = now_token
+                if recents:
+                    room_key = recents[0].internal_metadata.before
+                    prev_batch_token = now_token.copy_and_replace("room_key", room_key)
+
                 return TimelineBatch(
-                    events=recents, prev_batch=now_token, limited=False
+                    events=recents, prev_batch=prev_batch_token, limited=False
                 )
 
             filtering_factor = 2
@@ -745,7 +756,7 @@ class SyncHandler:
         """
         # TODO(mjark) Check if the state events were received by the server
         # after the previous sync, since we need to include those state
-        # updates even if they occured logically before the previous event.
+        # updates even if they occurred logically before the previous event.
         # TODO(mjark) Check for new redactions in the state events.
 
         with Measure(self.clock, "compute_state_delta"):
@@ -1014,10 +1025,14 @@ class SyncHandler:
         logger.debug("Fetching OTK data")
         device_id = sync_config.device_id
         one_time_key_counts = {}  # type: JsonDict
+        unused_fallback_key_types = []  # type: List[str]
         if device_id:
             one_time_key_counts = await self.store.count_e2e_one_time_keys(
                 user_id, device_id
             )
+            unused_fallback_key_types = await self.store.get_e2e_unused_fallback_key_types(
+                user_id, device_id
+            )
 
         logger.debug("Fetching group data")
         await self._generate_sync_entry_for_groups(sync_result_builder)
@@ -1041,6 +1056,7 @@ class SyncHandler:
             device_lists=device_lists,
             groups=sync_result_builder.groups,
             device_one_time_keys_count=one_time_key_counts,
+            device_unused_fallback_key_types=unused_fallback_key_types,
             next_batch=sync_result_builder.now_token,
         )
 
@@ -1378,13 +1394,16 @@ class SyncHandler:
                         return set(), set(), set(), set()
 
         ignored_account_data = await self.store.get_global_account_data_by_type_for_user(
-            "m.ignored_user_list", user_id=user_id
+            AccountDataTypes.IGNORED_USER_LIST, user_id=user_id
         )
 
+        # If there is ignored users account data and it matches the proper type,
+        # then use it.
+        ignored_users = frozenset()  # type: FrozenSet[str]
         if ignored_account_data:
-            ignored_users = ignored_account_data.get("ignored_users", {}).keys()
-        else:
-            ignored_users = frozenset()
+            ignored_users_data = ignored_account_data.get("ignored_users", {})
+            if isinstance(ignored_users_data, dict):
+                ignored_users = frozenset(ignored_users_data.keys())
 
         if since_token:
             room_changes = await self._get_rooms_changed(
@@ -1478,7 +1497,7 @@ class SyncHandler:
         return False
 
     async def _get_rooms_changed(
-        self, sync_result_builder: "SyncResultBuilder", ignored_users: Set[str]
+        self, sync_result_builder: "SyncResultBuilder", ignored_users: FrozenSet[str]
     ) -> _RoomChanges:
         """Gets the the changes that have happened since the last sync.
         """
@@ -1690,7 +1709,7 @@ class SyncHandler:
         return _RoomChanges(room_entries, invited, newly_joined_rooms, newly_left_rooms)
 
     async def _get_all_rooms(
-        self, sync_result_builder: "SyncResultBuilder", ignored_users: Set[str]
+        self, sync_result_builder: "SyncResultBuilder", ignored_users: FrozenSet[str]
     ) -> _RoomChanges:
         """Returns entries for all rooms for the user.
 
@@ -1764,7 +1783,7 @@ class SyncHandler:
     async def _generate_room_entry(
         self,
         sync_result_builder: "SyncResultBuilder",
-        ignored_users: Set[str],
+        ignored_users: FrozenSet[str],
         room_builder: "RoomSyncResultBuilder",
         ephemeral: List[JsonDict],
         tags: Optional[Dict[str, Dict[str, Any]]],
@@ -1865,7 +1884,7 @@ class SyncHandler:
         # members (as the client otherwise doesn't have enough info to form
         # the name itself).
         if sync_config.filter_collection.lazy_load_members() and (
-            # we recalulate the summary:
+            # we recalculate the summary:
             #   if there are membership changes in the timeline, or
             #   if membership has changed during a gappy sync, or
             #   if this is an initial sync.
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index 3cbfc2d780..e919a8f9ed 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -12,16 +12,16 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import logging
 import random
 from collections import namedtuple
 from typing import TYPE_CHECKING, List, Set, Tuple
 
 from synapse.api.errors import AuthError, ShadowBanError, SynapseError
+from synapse.appservice import ApplicationService
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.replication.tcp.streams import TypingStream
-from synapse.types import UserID, get_domain_from_id
+from synapse.types import JsonDict, UserID, get_domain_from_id
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 from synapse.util.metrics import Measure
 from synapse.util.wheel_timer import WheelTimer
@@ -167,20 +167,25 @@ class FollowerTypingHandler:
             now_typing = set(row.user_ids)
             self._room_typing[row.room_id] = row.user_ids
 
-            run_as_background_process(
-                "_handle_change_in_typing",
-                self._handle_change_in_typing,
-                row.room_id,
-                prev_typing,
-                now_typing,
-            )
+            if self.federation:
+                run_as_background_process(
+                    "_send_changes_in_typing_to_remotes",
+                    self._send_changes_in_typing_to_remotes,
+                    row.room_id,
+                    prev_typing,
+                    now_typing,
+                )
 
-    async def _handle_change_in_typing(
+    async def _send_changes_in_typing_to_remotes(
         self, room_id: str, prev_typing: Set[str], now_typing: Set[str]
     ):
         """Process a change in typing of a room from replication, sending EDUs
         for any local users.
         """
+
+        if not self.federation:
+            return
+
         for user_id in now_typing - prev_typing:
             if self.is_mine_id(user_id):
                 await self._push_remote(RoomMember(room_id, user_id), True)
@@ -371,7 +376,7 @@ class TypingWriterHandler(FollowerTypingHandler):
             between the requested tokens due to the limit.
 
             The token returned can be used in a subsequent call to this
-            function to get further updatees.
+            function to get further updates.
 
             The updates are a list of 2-tuples of stream ID and the row data
         """
@@ -430,6 +435,33 @@ class TypingNotificationEventSource:
             "content": {"user_ids": list(typing)},
         }
 
+    async def get_new_events_as(
+        self, from_key: int, service: ApplicationService
+    ) -> Tuple[List[JsonDict], int]:
+        """Returns a set of new typing events that an appservice
+        may be interested in.
+
+        Args:
+            from_key: the stream position at which events should be fetched from
+            service: The appservice which may be interested
+        """
+        with Measure(self.clock, "typing.get_new_events_as"):
+            from_key = int(from_key)
+            handler = self.get_typing_handler()
+
+            events = []
+            for room_id in handler._room_serials.keys():
+                if handler._room_serials[room_id] <= from_key:
+                    continue
+                if not await service.matches_user_in_member_list(
+                    room_id, handler.store
+                ):
+                    continue
+
+                events.append(self._make_event_for(room_id))
+
+            return (events, handler._latest_room_serial)
+
     async def get_new_events(self, from_key, room_ids, **kwargs):
         with Measure(self.clock, "typing.get_new_events"):
             from_key = int(from_key)
diff --git a/synapse/handlers/ui_auth/checkers.py b/synapse/handlers/ui_auth/checkers.py
index 9146dc1a3b..3d66bf305e 100644
--- a/synapse/handlers/ui_auth/checkers.py
+++ b/synapse/handlers/ui_auth/checkers.py
@@ -143,7 +143,7 @@ class _BaseThreepidAuthChecker:
 
         threepid_creds = authdict["threepid_creds"]
 
-        identity_handler = self.hs.get_handlers().identity_handler
+        identity_handler = self.hs.get_identity_handler()
 
         logger.info("Getting validated threepid. threepidcreds: %r", (threepid_creds,))
 
diff --git a/synapse/handlers/user_directory.py b/synapse/handlers/user_directory.py
index 79393c8829..afbebfc200 100644
--- a/synapse/handlers/user_directory.py
+++ b/synapse/handlers/user_directory.py
@@ -31,7 +31,7 @@ class UserDirectoryHandler(StateDeltasHandler):
     N.B.: ASSUMES IT IS THE ONLY THING THAT MODIFIES THE USER DIRECTORY
 
     The user directory is filled with users who this server can see are joined to a
-    world_readable or publically joinable room. We keep a database table up to date
+    world_readable or publicly joinable room. We keep a database table up to date
     by streaming changes of the current state and recalculating whether users should
     be in the directory or not when necessary.
     """
diff --git a/synapse/http/client.py b/synapse/http/client.py
index 8324632cb6..e5b13593f2 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -14,9 +14,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-import urllib
+import urllib.parse
 from io import BytesIO
 from typing import (
+    TYPE_CHECKING,
     Any,
     BinaryIO,
     Dict,
@@ -31,7 +32,7 @@ from typing import (
 
 import treq
 from canonicaljson import encode_canonical_json
-from netaddr import IPAddress
+from netaddr import IPAddress, IPSet
 from prometheus_client import Counter
 from zope.interface import implementer, provider
 
@@ -39,6 +40,8 @@ from OpenSSL import SSL
 from OpenSSL.SSL import VERIFY_NONE
 from twisted.internet import defer, error as twisted_error, protocol, ssl
 from twisted.internet.interfaces import (
+    IAddress,
+    IHostResolution,
     IReactorPluggableNameResolver,
     IResolutionReceiver,
 )
@@ -53,7 +56,7 @@ from twisted.web.client import (
 )
 from twisted.web.http import PotentialDataLoss
 from twisted.web.http_headers import Headers
-from twisted.web.iweb import IResponse
+from twisted.web.iweb import IAgent, IBodyProducer, IResponse
 
 from synapse.api.errors import Codes, HttpResponseException, SynapseError
 from synapse.http import QuieterFileBodyProducer, RequestTimedOutError, redact_uri
@@ -63,6 +66,9 @@ from synapse.logging.opentracing import set_tag, start_active_span, tags
 from synapse.util import json_decoder
 from synapse.util.async_helpers import timeout_deferred
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 outgoing_requests_counter = Counter("synapse_http_client_requests", "", ["method"])
@@ -84,12 +90,19 @@ QueryParamValue = Union[str, bytes, Iterable[Union[str, bytes]]]
 QueryParams = Union[Mapping[str, QueryParamValue], Mapping[bytes, QueryParamValue]]
 
 
-def check_against_blacklist(ip_address, ip_whitelist, ip_blacklist):
+def check_against_blacklist(
+    ip_address: IPAddress, ip_whitelist: Optional[IPSet], ip_blacklist: IPSet
+) -> bool:
     """
+    Compares an IP address to allowed and disallowed IP sets.
+
     Args:
-        ip_address (netaddr.IPAddress)
-        ip_whitelist (netaddr.IPSet)
-        ip_blacklist (netaddr.IPSet)
+        ip_address: The IP address to check
+        ip_whitelist: Allowed IP addresses.
+        ip_blacklist: Disallowed IP addresses.
+
+    Returns:
+        True if the IP address is in the blacklist and not in the whitelist.
     """
     if ip_address in ip_blacklist:
         if ip_whitelist is None or ip_address not in ip_whitelist:
@@ -118,23 +131,30 @@ class IPBlacklistingResolver:
     addresses, preventing DNS rebinding attacks on URL preview.
     """
 
-    def __init__(self, reactor, ip_whitelist, ip_blacklist):
+    def __init__(
+        self,
+        reactor: IReactorPluggableNameResolver,
+        ip_whitelist: Optional[IPSet],
+        ip_blacklist: IPSet,
+    ):
         """
         Args:
-            reactor (twisted.internet.reactor)
-            ip_whitelist (netaddr.IPSet)
-            ip_blacklist (netaddr.IPSet)
+            reactor: The twisted reactor.
+            ip_whitelist: IP addresses to allow.
+            ip_blacklist: IP addresses to disallow.
         """
         self._reactor = reactor
         self._ip_whitelist = ip_whitelist
         self._ip_blacklist = ip_blacklist
 
-    def resolveHostName(self, recv, hostname, portNumber=0):
+    def resolveHostName(
+        self, recv: IResolutionReceiver, hostname: str, portNumber: int = 0
+    ) -> IResolutionReceiver:
 
         r = recv()
-        addresses = []
+        addresses = []  # type: List[IAddress]
 
-        def _callback():
+        def _callback() -> None:
             r.resolutionBegan(None)
 
             has_bad_ip = False
@@ -161,15 +181,15 @@ class IPBlacklistingResolver:
         @provider(IResolutionReceiver)
         class EndpointReceiver:
             @staticmethod
-            def resolutionBegan(resolutionInProgress):
+            def resolutionBegan(resolutionInProgress: IHostResolution) -> None:
                 pass
 
             @staticmethod
-            def addressResolved(address):
+            def addressResolved(address: IAddress) -> None:
                 addresses.append(address)
 
             @staticmethod
-            def resolutionComplete():
+            def resolutionComplete() -> None:
                 _callback()
 
         self._reactor.nameResolver.resolveHostName(
@@ -185,19 +205,29 @@ class BlacklistingAgentWrapper(Agent):
     directly (without an IP address lookup).
     """
 
-    def __init__(self, agent, reactor, ip_whitelist=None, ip_blacklist=None):
+    def __init__(
+        self,
+        agent: IAgent,
+        ip_whitelist: Optional[IPSet] = None,
+        ip_blacklist: Optional[IPSet] = None,
+    ):
         """
         Args:
-            agent (twisted.web.client.Agent): The Agent to wrap.
-            reactor (twisted.internet.reactor)
-            ip_whitelist (netaddr.IPSet)
-            ip_blacklist (netaddr.IPSet)
+            agent: The Agent to wrap.
+            ip_whitelist: IP addresses to allow.
+            ip_blacklist: IP addresses to disallow.
         """
         self._agent = agent
         self._ip_whitelist = ip_whitelist
         self._ip_blacklist = ip_blacklist
 
-    def request(self, method, uri, headers=None, bodyProducer=None):
+    def request(
+        self,
+        method: bytes,
+        uri: bytes,
+        headers: Optional[Headers] = None,
+        bodyProducer: Optional[IBodyProducer] = None,
+    ) -> defer.Deferred:
         h = urllib.parse.urlparse(uri.decode("ascii"))
 
         try:
@@ -226,23 +256,23 @@ class SimpleHttpClient:
 
     def __init__(
         self,
-        hs,
-        treq_args={},
-        ip_whitelist=None,
-        ip_blacklist=None,
-        http_proxy=None,
-        https_proxy=None,
+        hs: "HomeServer",
+        treq_args: Dict[str, Any] = {},
+        ip_whitelist: Optional[IPSet] = None,
+        ip_blacklist: Optional[IPSet] = None,
+        http_proxy: Optional[bytes] = None,
+        https_proxy: Optional[bytes] = None,
     ):
         """
         Args:
-            hs (synapse.server.HomeServer)
-            treq_args (dict): Extra keyword arguments to be given to treq.request.
-            ip_blacklist (netaddr.IPSet): The IP addresses that are blacklisted that
+            hs
+            treq_args: Extra keyword arguments to be given to treq.request.
+            ip_blacklist: The IP addresses that are blacklisted that
                 we may not request.
-            ip_whitelist (netaddr.IPSet): The whitelisted IP addresses, that we can
+            ip_whitelist: The whitelisted IP addresses, that we can
                request if it were otherwise caught in a blacklist.
-            http_proxy (bytes): proxy server to use for http connections. host[:port]
-            https_proxy (bytes): proxy server to use for https connections. host[:port]
+            http_proxy: proxy server to use for http connections. host[:port]
+            https_proxy: proxy server to use for https connections. host[:port]
         """
         self.hs = hs
 
@@ -306,7 +336,6 @@ class SimpleHttpClient:
             # by the DNS resolution.
             self.agent = BlacklistingAgentWrapper(
                 self.agent,
-                self.reactor,
                 ip_whitelist=self._ip_whitelist,
                 ip_blacklist=self._ip_blacklist,
             )
@@ -359,7 +388,7 @@ class SimpleHttpClient:
                     agent=self.agent,
                     data=body_producer,
                     headers=headers,
-                    **self._extra_treq_args
+                    **self._extra_treq_args,
                 )  # type: defer.Deferred
 
                 # we use our own timeout mechanism rather than treq's as a workaround
@@ -397,7 +426,7 @@ class SimpleHttpClient:
     async def post_urlencoded_get_json(
         self,
         uri: str,
-        args: Mapping[str, Union[str, List[str]]] = {},
+        args: Optional[Mapping[str, Union[str, List[str]]]] = None,
         headers: Optional[RawHeaders] = None,
     ) -> Any:
         """
@@ -422,9 +451,7 @@ class SimpleHttpClient:
         # TODO: Do we ever want to log message contents?
         logger.debug("post_urlencoded_get_json args: %s", args)
 
-        query_bytes = urllib.parse.urlencode(encode_urlencode_args(args), True).encode(
-            "utf8"
-        )
+        query_bytes = encode_query_args(args)
 
         actual_headers = {
             b"Content-Type": [b"application/x-www-form-urlencoded"],
@@ -432,7 +459,7 @@ class SimpleHttpClient:
             b"Accept": [b"application/json"],
         }
         if headers:
-            actual_headers.update(headers)
+            actual_headers.update(headers)  # type: ignore
 
         response = await self.request(
             "POST", uri, headers=Headers(actual_headers), data=query_bytes
@@ -479,7 +506,7 @@ class SimpleHttpClient:
             b"Accept": [b"application/json"],
         }
         if headers:
-            actual_headers.update(headers)
+            actual_headers.update(headers)  # type: ignore
 
         response = await self.request(
             "POST", uri, headers=Headers(actual_headers), data=json_str
@@ -495,7 +522,10 @@ class SimpleHttpClient:
             )
 
     async def get_json(
-        self, uri: str, args: QueryParams = {}, headers: Optional[RawHeaders] = None,
+        self,
+        uri: str,
+        args: Optional[QueryParams] = None,
+        headers: Optional[RawHeaders] = None,
     ) -> Any:
         """Gets some json from the given URI.
 
@@ -516,7 +546,7 @@ class SimpleHttpClient:
         """
         actual_headers = {b"Accept": [b"application/json"]}
         if headers:
-            actual_headers.update(headers)
+            actual_headers.update(headers)  # type: ignore
 
         body = await self.get_raw(uri, args, headers=headers)
         return json_decoder.decode(body.decode("utf-8"))
@@ -525,7 +555,7 @@ class SimpleHttpClient:
         self,
         uri: str,
         json_body: Any,
-        args: QueryParams = {},
+        args: Optional[QueryParams] = None,
         headers: RawHeaders = None,
     ) -> Any:
         """Puts some json to the given URI.
@@ -546,9 +576,9 @@ class SimpleHttpClient:
 
             ValueError: if the response was not JSON
         """
-        if len(args):
-            query_bytes = urllib.parse.urlencode(args, True)
-            uri = "%s?%s" % (uri, query_bytes)
+        if args:
+            query_str = urllib.parse.urlencode(args, True)
+            uri = "%s?%s" % (uri, query_str)
 
         json_str = encode_canonical_json(json_body)
 
@@ -558,7 +588,7 @@ class SimpleHttpClient:
             b"Accept": [b"application/json"],
         }
         if headers:
-            actual_headers.update(headers)
+            actual_headers.update(headers)  # type: ignore
 
         response = await self.request(
             "PUT", uri, headers=Headers(actual_headers), data=json_str
@@ -574,7 +604,10 @@ class SimpleHttpClient:
             )
 
     async def get_raw(
-        self, uri: str, args: QueryParams = {}, headers: Optional[RawHeaders] = None
+        self,
+        uri: str,
+        args: Optional[QueryParams] = None,
+        headers: Optional[RawHeaders] = None,
     ) -> bytes:
         """Gets raw text from the given URI.
 
@@ -592,13 +625,13 @@ class SimpleHttpClient:
 
             HttpResponseException on a non-2xx HTTP response.
         """
-        if len(args):
-            query_bytes = urllib.parse.urlencode(args, True)
-            uri = "%s?%s" % (uri, query_bytes)
+        if args:
+            query_str = urllib.parse.urlencode(args, True)
+            uri = "%s?%s" % (uri, query_str)
 
         actual_headers = {b"User-Agent": [self.user_agent]}
         if headers:
-            actual_headers.update(headers)
+            actual_headers.update(headers)  # type: ignore
 
         response = await self.request("GET", uri, headers=Headers(actual_headers))
 
@@ -641,7 +674,7 @@ class SimpleHttpClient:
 
         actual_headers = {b"User-Agent": [self.user_agent]}
         if headers:
-            actual_headers.update(headers)
+            actual_headers.update(headers)  # type: ignore
 
         response = await self.request("GET", url, headers=Headers(actual_headers))
 
@@ -649,12 +682,13 @@ class SimpleHttpClient:
 
         if (
             b"Content-Length" in resp_headers
+            and max_size
             and int(resp_headers[b"Content-Length"][0]) > max_size
         ):
-            logger.warning("Requested URL is too large > %r bytes" % (self.max_size,))
+            logger.warning("Requested URL is too large > %r bytes" % (max_size,))
             raise SynapseError(
                 502,
-                "Requested file is too large > %r bytes" % (self.max_size,),
+                "Requested file is too large > %r bytes" % (max_size,),
                 Codes.TOO_LARGE,
             )
 
@@ -668,7 +702,7 @@ class SimpleHttpClient:
 
         try:
             length = await make_deferred_yieldable(
-                _readBodyToFile(response, output_stream, max_size)
+                readBodyToFile(response, output_stream, max_size)
             )
         except SynapseError:
             # This can happen e.g. because the body is too large.
@@ -696,18 +730,16 @@ def _timeout_to_request_timed_out_error(f: Failure):
     return f
 
 
-# XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
-# The two should be factored out.
-
-
 class _ReadBodyToFileProtocol(protocol.Protocol):
-    def __init__(self, stream, deferred, max_size):
+    def __init__(
+        self, stream: BinaryIO, deferred: defer.Deferred, max_size: Optional[int]
+    ):
         self.stream = stream
         self.deferred = deferred
         self.length = 0
         self.max_size = max_size
 
-    def dataReceived(self, data):
+    def dataReceived(self, data: bytes) -> None:
         self.stream.write(data)
         self.length += len(data)
         if self.max_size is not None and self.length >= self.max_size:
@@ -721,7 +753,7 @@ class _ReadBodyToFileProtocol(protocol.Protocol):
             self.deferred = defer.Deferred()
             self.transport.loseConnection()
 
-    def connectionLost(self, reason):
+    def connectionLost(self, reason: Failure) -> None:
         if reason.check(ResponseDone):
             self.deferred.callback(self.length)
         elif reason.check(PotentialDataLoss):
@@ -732,35 +764,48 @@ class _ReadBodyToFileProtocol(protocol.Protocol):
             self.deferred.errback(reason)
 
 
-# XXX: FIXME: This is horribly copy-pasted from matrixfederationclient.
-# The two should be factored out.
+def readBodyToFile(
+    response: IResponse, stream: BinaryIO, max_size: Optional[int]
+) -> defer.Deferred:
+    """
+    Read a HTTP response body to a file-object. Optionally enforcing a maximum file size.
 
+    Args:
+        response: The HTTP response to read from.
+        stream: The file-object to write to.
+        max_size: The maximum file size to allow.
+
+    Returns:
+        A Deferred which resolves to the length of the read body.
+    """
 
-def _readBodyToFile(response, stream, max_size):
     d = defer.Deferred()
     response.deliverBody(_ReadBodyToFileProtocol(stream, d, max_size))
     return d
 
 
-def encode_urlencode_args(args):
-    return {k: encode_urlencode_arg(v) for k, v in args.items()}
+def encode_query_args(args: Optional[Mapping[str, Union[str, List[str]]]]) -> bytes:
+    """
+    Encodes a map of query arguments to bytes which can be appended to a URL.
 
+    Args:
+        args: The query arguments, a mapping of string to string or list of strings.
 
-def encode_urlencode_arg(arg):
-    if isinstance(arg, str):
-        return arg.encode("utf-8")
-    elif isinstance(arg, list):
-        return [encode_urlencode_arg(i) for i in arg]
-    else:
-        return arg
+    Returns:
+        The query arguments encoded as bytes.
+    """
+    if args is None:
+        return b""
 
+    encoded_args = {}
+    for k, vs in args.items():
+        if isinstance(vs, str):
+            vs = [vs]
+        encoded_args[k] = [v.encode("utf8") for v in vs]
 
-def _print_ex(e):
-    if hasattr(e, "reasons") and e.reasons:
-        for ex in e.reasons:
-            _print_ex(ex)
-    else:
-        logger.exception(e)
+    query_str = urllib.parse.urlencode(encoded_args, True)
+
+    return query_str.encode("utf8")
 
 
 class InsecureInterceptableContextFactory(ssl.ContextFactory):
diff --git a/synapse/http/federation/matrix_federation_agent.py b/synapse/http/federation/matrix_federation_agent.py
index 83d6196d4a..e77f9587d0 100644
--- a/synapse/http/federation/matrix_federation_agent.py
+++ b/synapse/http/federation/matrix_federation_agent.py
@@ -12,21 +12,25 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import logging
-import urllib
-from typing import List
+import urllib.parse
+from typing import List, Optional
 
 from netaddr import AddrFormatError, IPAddress
 from zope.interface import implementer
 
 from twisted.internet import defer
 from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
-from twisted.internet.interfaces import IStreamClientEndpoint
-from twisted.web.client import Agent, HTTPConnectionPool
+from twisted.internet.interfaces import (
+    IProtocolFactory,
+    IReactorCore,
+    IStreamClientEndpoint,
+)
+from twisted.web.client import URI, Agent, HTTPConnectionPool
 from twisted.web.http_headers import Headers
-from twisted.web.iweb import IAgent, IAgentEndpointFactory
+from twisted.web.iweb import IAgent, IAgentEndpointFactory, IBodyProducer
 
+from synapse.crypto.context_factory import FederationPolicyForHTTPS
 from synapse.http.federation.srv_resolver import Server, SrvResolver
 from synapse.http.federation.well_known_resolver import WellKnownResolver
 from synapse.logging.context import make_deferred_yieldable, run_in_background
@@ -44,30 +48,30 @@ class MatrixFederationAgent:
     Doesn't implement any retries. (Those are done in MatrixFederationHttpClient.)
 
     Args:
-        reactor (IReactor): twisted reactor to use for underlying requests
+        reactor: twisted reactor to use for underlying requests
 
-        tls_client_options_factory (FederationPolicyForHTTPS|None):
+        tls_client_options_factory:
             factory to use for fetching client tls options, or none to disable TLS.
 
-        user_agent (bytes):
+        user_agent:
             The user agent header to use for federation requests.
 
-        _srv_resolver (SrvResolver|None):
-            SRVResolver impl to use for looking up SRV records. None to use a default
-            implementation.
+        _srv_resolver:
+            SrvResolver implementation to use for looking up SRV records. None
+            to use a default implementation.
 
-        _well_known_resolver (WellKnownResolver|None):
+        _well_known_resolver:
             WellKnownResolver to use to perform well-known lookups. None to use a
             default implementation.
     """
 
     def __init__(
         self,
-        reactor,
-        tls_client_options_factory,
-        user_agent,
-        _srv_resolver=None,
-        _well_known_resolver=None,
+        reactor: IReactorCore,
+        tls_client_options_factory: Optional[FederationPolicyForHTTPS],
+        user_agent: bytes,
+        _srv_resolver: Optional[SrvResolver] = None,
+        _well_known_resolver: Optional[WellKnownResolver] = None,
     ):
         self._reactor = reactor
         self._clock = Clock(reactor)
@@ -99,15 +103,20 @@ class MatrixFederationAgent:
         self._well_known_resolver = _well_known_resolver
 
     @defer.inlineCallbacks
-    def request(self, method, uri, headers=None, bodyProducer=None):
+    def request(
+        self,
+        method: bytes,
+        uri: bytes,
+        headers: Optional[Headers] = None,
+        bodyProducer: Optional[IBodyProducer] = None,
+    ) -> defer.Deferred:
         """
         Args:
-            method (bytes): HTTP method: GET/POST/etc
-            uri (bytes): Absolute URI to be retrieved
-            headers (twisted.web.http_headers.Headers|None):
-                HTTP headers to send with the request, or None to
-                send no extra headers.
-            bodyProducer (twisted.web.iweb.IBodyProducer|None):
+            method: HTTP method: GET/POST/etc
+            uri: Absolute URI to be retrieved
+            headers:
+                HTTP headers to send with the request, or None to send no extra headers.
+            bodyProducer:
                 An object which can generate bytes to make up the
                 body of this request (for example, the properly encoded contents of
                 a file for a file upload).  Or None if the request is to have
@@ -123,6 +132,9 @@ class MatrixFederationAgent:
         # explicit port.
         parsed_uri = urllib.parse.urlparse(uri)
 
+        # There must be a valid hostname.
+        assert parsed_uri.hostname
+
         # If this is a matrix:// URI check if the server has delegated matrix
         # traffic using well-known delegation.
         #
@@ -179,7 +191,12 @@ class MatrixHostnameEndpointFactory:
     """Factory for MatrixHostnameEndpoint for parsing to an Agent.
     """
 
-    def __init__(self, reactor, tls_client_options_factory, srv_resolver):
+    def __init__(
+        self,
+        reactor: IReactorCore,
+        tls_client_options_factory: Optional[FederationPolicyForHTTPS],
+        srv_resolver: Optional[SrvResolver],
+    ):
         self._reactor = reactor
         self._tls_client_options_factory = tls_client_options_factory
 
@@ -203,15 +220,20 @@ class MatrixHostnameEndpoint:
     resolution (i.e. via SRV). Does not check for well-known delegation.
 
     Args:
-        reactor (IReactor)
-        tls_client_options_factory (ClientTLSOptionsFactory|None):
+        reactor: twisted reactor to use for underlying requests
+        tls_client_options_factory:
             factory to use for fetching client tls options, or none to disable TLS.
-        srv_resolver (SrvResolver): The SRV resolver to use
-        parsed_uri (twisted.web.client.URI): The parsed URI that we're wanting
-            to connect to.
+        srv_resolver: The SRV resolver to use
+        parsed_uri: The parsed URI that we're wanting to connect to.
     """
 
-    def __init__(self, reactor, tls_client_options_factory, srv_resolver, parsed_uri):
+    def __init__(
+        self,
+        reactor: IReactorCore,
+        tls_client_options_factory: Optional[FederationPolicyForHTTPS],
+        srv_resolver: SrvResolver,
+        parsed_uri: URI,
+    ):
         self._reactor = reactor
 
         self._parsed_uri = parsed_uri
@@ -231,13 +253,13 @@ class MatrixHostnameEndpoint:
 
         self._srv_resolver = srv_resolver
 
-    def connect(self, protocol_factory):
+    def connect(self, protocol_factory: IProtocolFactory) -> defer.Deferred:
         """Implements IStreamClientEndpoint interface
         """
 
         return run_in_background(self._do_connect, protocol_factory)
 
-    async def _do_connect(self, protocol_factory):
+    async def _do_connect(self, protocol_factory: IProtocolFactory) -> None:
         first_exception = None
 
         server_list = await self._resolve_server()
@@ -303,20 +325,20 @@ class MatrixHostnameEndpoint:
         return [Server(host, 8448)]
 
 
-def _is_ip_literal(host):
+def _is_ip_literal(host: bytes) -> bool:
     """Test if the given host name is either an IPv4 or IPv6 literal.
 
     Args:
-        host (bytes)
+        host: The host name to check
 
     Returns:
-        bool
+        True if the hostname is an IP address literal.
     """
 
-    host = host.decode("ascii")
+    host_str = host.decode("ascii")
 
     try:
-        IPAddress(host)
+        IPAddress(host_str)
         return True
     except AddrFormatError:
         return False
diff --git a/synapse/http/federation/well_known_resolver.py b/synapse/http/federation/well_known_resolver.py
index a306faa267..5e08ef1664 100644
--- a/synapse/http/federation/well_known_resolver.py
+++ b/synapse/http/federation/well_known_resolver.py
@@ -12,7 +12,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import logging
 import random
 import time
@@ -21,10 +20,11 @@ from typing import Callable, Dict, Optional, Tuple
 import attr
 
 from twisted.internet import defer
+from twisted.internet.interfaces import IReactorTime
 from twisted.web.client import RedirectAgent, readBody
 from twisted.web.http import stringToDatetime
 from twisted.web.http_headers import Headers
-from twisted.web.iweb import IResponse
+from twisted.web.iweb import IAgent, IResponse
 
 from synapse.logging.context import make_deferred_yieldable
 from synapse.util import Clock, json_decoder
@@ -81,11 +81,11 @@ class WellKnownResolver:
 
     def __init__(
         self,
-        reactor,
-        agent,
-        user_agent,
-        well_known_cache=None,
-        had_well_known_cache=None,
+        reactor: IReactorTime,
+        agent: IAgent,
+        user_agent: bytes,
+        well_known_cache: Optional[TTLCache] = None,
+        had_well_known_cache: Optional[TTLCache] = None,
     ):
         self._reactor = reactor
         self._clock = Clock(reactor)
@@ -127,7 +127,7 @@ class WellKnownResolver:
             with Measure(self._clock, "get_well_known"):
                 result, cache_period = await self._fetch_well_known(
                     server_name
-                )  # type: Tuple[Optional[bytes], float]
+                )  # type: Optional[bytes], float
 
         except _FetchWellKnownFailure as e:
             if prev_result and e.temporary:
@@ -172,7 +172,7 @@ class WellKnownResolver:
         had_valid_well_known = self._had_valid_well_known_cache.get(server_name, False)
 
         # We do this in two steps to differentiate between possibly transient
-        # errors (e.g. can't connect to host, 503 response) and more permenant
+        # errors (e.g. can't connect to host, 503 response) and more permanent
         # errors (such as getting a 404 response).
         response, body = await self._make_well_known_request(
             server_name, retry=had_valid_well_known
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index c23a4d7c0c..4e27f93b7a 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -17,8 +17,9 @@ import cgi
 import logging
 import random
 import sys
-import urllib
+import urllib.parse
 from io import BytesIO
+from typing import Callable, Dict, List, Optional, Tuple, Union
 
 import attr
 import treq
@@ -27,25 +28,27 @@ from prometheus_client import Counter
 from signedjson.sign import sign_json
 from zope.interface import implementer
 
-from twisted.internet import defer, protocol
+from twisted.internet import defer
 from twisted.internet.error import DNSLookupError
 from twisted.internet.interfaces import IReactorPluggableNameResolver, IReactorTime
 from twisted.internet.task import _EPSILON, Cooperator
-from twisted.web._newclient import ResponseDone
 from twisted.web.http_headers import Headers
-from twisted.web.iweb import IResponse
+from twisted.web.iweb import IBodyProducer, IResponse
 
 import synapse.metrics
 import synapse.util.retryutils
 from synapse.api.errors import (
-    Codes,
     FederationDeniedError,
     HttpResponseException,
     RequestSendFailed,
-    SynapseError,
 )
 from synapse.http import QuieterFileBodyProducer
-from synapse.http.client import BlacklistingAgentWrapper, IPBlacklistingResolver
+from synapse.http.client import (
+    BlacklistingAgentWrapper,
+    IPBlacklistingResolver,
+    encode_query_args,
+    readBodyToFile,
+)
 from synapse.http.federation.matrix_federation_agent import MatrixFederationAgent
 from synapse.logging.context import make_deferred_yieldable
 from synapse.logging.opentracing import (
@@ -54,6 +57,7 @@ from synapse.logging.opentracing import (
     start_active_span,
     tags,
 )
+from synapse.types import JsonDict
 from synapse.util import json_decoder
 from synapse.util.async_helpers import timeout_deferred
 from synapse.util.metrics import Measure
@@ -76,47 +80,44 @@ MAXINT = sys.maxsize
 _next_id = 1
 
 
+QueryArgs = Dict[str, Union[str, List[str]]]
+
+
 @attr.s(slots=True, frozen=True)
 class MatrixFederationRequest:
-    method = attr.ib()
+    method = attr.ib(type=str)
     """HTTP method
-    :type: str
     """
 
-    path = attr.ib()
+    path = attr.ib(type=str)
     """HTTP path
-    :type: str
     """
 
-    destination = attr.ib()
+    destination = attr.ib(type=str)
     """The remote server to send the HTTP request to.
-    :type: str"""
+    """
 
-    json = attr.ib(default=None)
+    json = attr.ib(default=None, type=Optional[JsonDict])
     """JSON to send in the body.
-    :type: dict|None
     """
 
-    json_callback = attr.ib(default=None)
+    json_callback = attr.ib(default=None, type=Optional[Callable[[], JsonDict]])
     """A callback to generate the JSON.
-    :type: func|None
     """
 
-    query = attr.ib(default=None)
+    query = attr.ib(default=None, type=Optional[dict])
     """Query arguments.
-    :type: dict|None
     """
 
-    txn_id = attr.ib(default=None)
+    txn_id = attr.ib(default=None, type=Optional[str])
     """Unique ID for this request (for logging)
-    :type: str|None
     """
 
     uri = attr.ib(init=False, type=bytes)
     """The URI of this request
     """
 
-    def __attrs_post_init__(self):
+    def __attrs_post_init__(self) -> None:
         global _next_id
         txn_id = "%s-O-%s" % (self.method, _next_id)
         _next_id = (_next_id + 1) % (MAXINT - 1)
@@ -136,7 +137,7 @@ class MatrixFederationRequest:
         )
         object.__setattr__(self, "uri", uri)
 
-    def get_json(self):
+    def get_json(self) -> Optional[JsonDict]:
         if self.json_callback:
             return self.json_callback()
         return self.json
@@ -148,7 +149,7 @@ async def _handle_json_response(
     request: MatrixFederationRequest,
     response: IResponse,
     start_ms: int,
-):
+) -> JsonDict:
     """
     Reads the JSON body of a response, with a timeout
 
@@ -160,7 +161,7 @@ async def _handle_json_response(
         start_ms: Timestamp when request was made
 
     Returns:
-        dict: parsed JSON response
+        The parsed JSON response
     """
     try:
         check_content_type_is_json(response.headers)
@@ -250,9 +251,7 @@ class MatrixFederationHttpClient:
         # Use a BlacklistingAgentWrapper to prevent circumventing the IP
         # blacklist via IP literals in server names
         self.agent = BlacklistingAgentWrapper(
-            self.agent,
-            self.reactor,
-            ip_blacklist=hs.config.federation_ip_range_blacklist,
+            self.agent, ip_blacklist=hs.config.federation_ip_range_blacklist,
         )
 
         self.clock = hs.get_clock()
@@ -266,27 +265,29 @@ class MatrixFederationHttpClient:
         self._cooperator = Cooperator(scheduler=schedule)
 
     async def _send_request_with_optional_trailing_slash(
-        self, request, try_trailing_slash_on_400=False, **send_request_args
-    ):
+        self,
+        request: MatrixFederationRequest,
+        try_trailing_slash_on_400: bool = False,
+        **send_request_args
+    ) -> IResponse:
         """Wrapper for _send_request which can optionally retry the request
         upon receiving a combination of a 400 HTTP response code and a
         'M_UNRECOGNIZED' errcode. This is a workaround for Synapse <= v0.99.3
         due to #3622.
 
         Args:
-            request (MatrixFederationRequest): details of request to be sent
-            try_trailing_slash_on_400 (bool): Whether on receiving a 400
+            request: details of request to be sent
+            try_trailing_slash_on_400: Whether on receiving a 400
                 'M_UNRECOGNIZED' from the server to retry the request with a
                 trailing slash appended to the request path.
-            send_request_args (Dict): A dictionary of arguments to pass to
-                `_send_request()`.
+            send_request_args: A dictionary of arguments to pass to `_send_request()`.
 
         Raises:
             HttpResponseException: If we get an HTTP response code >= 300
                 (except 429).
 
         Returns:
-            Dict: Parsed JSON response body.
+            Parsed JSON response body.
         """
         try:
             response = await self._send_request(request, **send_request_args)
@@ -313,24 +314,26 @@ class MatrixFederationHttpClient:
 
     async def _send_request(
         self,
-        request,
-        retry_on_dns_fail=True,
-        timeout=None,
-        long_retries=False,
-        ignore_backoff=False,
-        backoff_on_404=False,
-    ):
+        request: MatrixFederationRequest,
+        retry_on_dns_fail: bool = True,
+        timeout: Optional[int] = None,
+        long_retries: bool = False,
+        ignore_backoff: bool = False,
+        backoff_on_404: bool = False,
+    ) -> IResponse:
         """
         Sends a request to the given server.
 
         Args:
-            request (MatrixFederationRequest): details of request to be sent
+            request: details of request to be sent
 
-            timeout (int|None): number of milliseconds to wait for the response headers
+            retry_on_dns_fail: true if the request should be retied on DNS failures
+
+            timeout: number of milliseconds to wait for the response headers
                 (including connecting to the server), *for each attempt*.
                 60s by default.
 
-            long_retries (bool): whether to use the long retry algorithm.
+            long_retries: whether to use the long retry algorithm.
 
                 The regular retry algorithm makes 4 attempts, with intervals
                 [0.5s, 1s, 2s].
@@ -346,14 +349,13 @@ class MatrixFederationHttpClient:
                 NB: the long retry algorithm takes over 20 minutes to complete, with
                 a default timeout of 60s!
 
-            ignore_backoff (bool): true to ignore the historical backoff data
+            ignore_backoff: true to ignore the historical backoff data
                 and try the request anyway.
 
-            backoff_on_404 (bool): Back off if we get a 404
+            backoff_on_404: Back off if we get a 404
 
         Returns:
-            twisted.web.client.Response: resolves with the HTTP
-            response object on success.
+            Resolves with the HTTP response object on success.
 
         Raises:
             HttpResponseException: If we get an HTTP response code >= 300
@@ -404,7 +406,7 @@ class MatrixFederationHttpClient:
         )
 
         # Inject the span into the headers
-        headers_dict = {}
+        headers_dict = {}  # type: Dict[bytes, List[bytes]]
         inject_active_span_byte_dict(headers_dict, request.destination)
 
         headers_dict[b"User-Agent"] = [self.version_string_bytes]
@@ -435,7 +437,7 @@ class MatrixFederationHttpClient:
                         data = encode_canonical_json(json)
                         producer = QuieterFileBodyProducer(
                             BytesIO(data), cooperator=self._cooperator
-                        )
+                        )  # type: Optional[IBodyProducer]
                     else:
                         producer = None
                         auth_headers = self.build_auth_headers(
@@ -524,14 +526,16 @@ class MatrixFederationHttpClient:
                             )
                             body = None
 
-                        e = HttpResponseException(response.code, response_phrase, body)
+                        exc = HttpResponseException(
+                            response.code, response_phrase, body
+                        )
 
                         # Retry if the error is a 429 (Too Many Requests),
                         # otherwise just raise a standard HttpResponseException
                         if response.code == 429:
-                            raise RequestSendFailed(e, can_retry=True) from e
+                            raise RequestSendFailed(exc, can_retry=True) from exc
                         else:
-                            raise e
+                            raise exc
 
                     break
                 except RequestSendFailed as e:
@@ -582,22 +586,27 @@ class MatrixFederationHttpClient:
         return response
 
     def build_auth_headers(
-        self, destination, method, url_bytes, content=None, destination_is=None
-    ):
+        self,
+        destination: Optional[bytes],
+        method: bytes,
+        url_bytes: bytes,
+        content: Optional[JsonDict] = None,
+        destination_is: Optional[bytes] = None,
+    ) -> List[bytes]:
         """
         Builds the Authorization headers for a federation request
         Args:
-            destination (bytes|None): The desination homeserver of the request.
+            destination: The destination homeserver of the request.
                 May be None if the destination is an identity server, in which case
                 destination_is must be non-None.
-            method (bytes): The HTTP method of the request
-            url_bytes (bytes): The URI path of the request
-            content (object): The body of the request
-            destination_is (bytes): As 'destination', but if the destination is an
+            method: The HTTP method of the request
+            url_bytes: The URI path of the request
+            content: The body of the request
+            destination_is: As 'destination', but if the destination is an
                 identity server
 
         Returns:
-            list[bytes]: a list of headers to be added as "Authorization:" headers
+            A list of headers to be added as "Authorization:" headers
         """
         request = {
             "method": method.decode("ascii"),
@@ -629,33 +638,32 @@ class MatrixFederationHttpClient:
 
     async def put_json(
         self,
-        destination,
-        path,
-        args={},
-        data={},
-        json_data_callback=None,
-        long_retries=False,
-        timeout=None,
-        ignore_backoff=False,
-        backoff_on_404=False,
-        try_trailing_slash_on_400=False,
-    ):
-        """ Sends the specifed json data using PUT
+        destination: str,
+        path: str,
+        args: Optional[QueryArgs] = None,
+        data: Optional[JsonDict] = None,
+        json_data_callback: Optional[Callable[[], JsonDict]] = None,
+        long_retries: bool = False,
+        timeout: Optional[int] = None,
+        ignore_backoff: bool = False,
+        backoff_on_404: bool = False,
+        try_trailing_slash_on_400: bool = False,
+    ) -> Union[JsonDict, list]:
+        """ Sends the specified json data using PUT
 
         Args:
-            destination (str): The remote server to send the HTTP request
-                to.
-            path (str): The HTTP path.
-            args (dict): query params
-            data (dict): A dict containing the data that will be used as
+            destination: The remote server to send the HTTP request to.
+            path: The HTTP path.
+            args: query params
+            data: A dict containing the data that will be used as
                 the request body. This will be encoded as JSON.
-            json_data_callback (callable): A callable returning the dict to
+            json_data_callback: A callable returning the dict to
                 use as the request body.
 
-            long_retries (bool): whether to use the long retry algorithm. See
+            long_retries: whether to use the long retry algorithm. See
                 docs on _send_request for details.
 
-            timeout (int|None): number of milliseconds to wait for the response.
+            timeout: number of milliseconds to wait for the response.
                 self._default_timeout (60s) by default.
 
                 Note that we may make several attempts to send the request; this
@@ -663,19 +671,19 @@ class MatrixFederationHttpClient:
                 *each* attempt (including connection time) as well as the time spent
                 reading the response body after a 200 response.
 
-            ignore_backoff (bool): true to ignore the historical backoff data
+            ignore_backoff: true to ignore the historical backoff data
                 and try the request anyway.
-            backoff_on_404 (bool): True if we should count a 404 response as
+            backoff_on_404: True if we should count a 404 response as
                 a failure of the server (and should therefore back off future
                 requests).
-            try_trailing_slash_on_400 (bool): True if on a 400 M_UNRECOGNIZED
+            try_trailing_slash_on_400: True if on a 400 M_UNRECOGNIZED
                 response we should try appending a trailing slash to the end
                 of the request. Workaround for #3622 in Synapse <= v0.99.3. This
                 will be attempted before backing off if backing off has been
                 enabled.
 
         Returns:
-            dict|list: Succeeds when we get a 2xx HTTP response. The
+            Succeeds when we get a 2xx HTTP response. The
             result will be the decoded JSON body.
 
         Raises:
@@ -721,29 +729,28 @@ class MatrixFederationHttpClient:
 
     async def post_json(
         self,
-        destination,
-        path,
-        data={},
-        long_retries=False,
-        timeout=None,
-        ignore_backoff=False,
-        args={},
-    ):
-        """ Sends the specifed json data using POST
+        destination: str,
+        path: str,
+        data: Optional[JsonDict] = None,
+        long_retries: bool = False,
+        timeout: Optional[int] = None,
+        ignore_backoff: bool = False,
+        args: Optional[QueryArgs] = None,
+    ) -> Union[JsonDict, list]:
+        """ Sends the specified json data using POST
 
         Args:
-            destination (str): The remote server to send the HTTP request
-                to.
+            destination: The remote server to send the HTTP request to.
 
-            path (str): The HTTP path.
+            path: The HTTP path.
 
-            data (dict): A dict containing the data that will be used as
+            data: A dict containing the data that will be used as
                 the request body. This will be encoded as JSON.
 
-            long_retries (bool): whether to use the long retry algorithm. See
+            long_retries: whether to use the long retry algorithm. See
                 docs on _send_request for details.
 
-            timeout (int|None): number of milliseconds to wait for the response.
+            timeout: number of milliseconds to wait for the response.
                 self._default_timeout (60s) by default.
 
                 Note that we may make several attempts to send the request; this
@@ -751,10 +758,10 @@ class MatrixFederationHttpClient:
                 *each* attempt (including connection time) as well as the time spent
                 reading the response body after a 200 response.
 
-            ignore_backoff (bool): true to ignore the historical backoff data and
+            ignore_backoff: true to ignore the historical backoff data and
                 try the request anyway.
 
-            args (dict): query params
+            args: query params
         Returns:
             dict|list: Succeeds when we get a 2xx HTTP response. The
             result will be the decoded JSON body.
@@ -795,26 +802,25 @@ class MatrixFederationHttpClient:
 
     async def get_json(
         self,
-        destination,
-        path,
-        args=None,
-        retry_on_dns_fail=True,
-        timeout=None,
-        ignore_backoff=False,
-        try_trailing_slash_on_400=False,
-    ):
+        destination: str,
+        path: str,
+        args: Optional[QueryArgs] = None,
+        retry_on_dns_fail: bool = True,
+        timeout: Optional[int] = None,
+        ignore_backoff: bool = False,
+        try_trailing_slash_on_400: bool = False,
+    ) -> Union[JsonDict, list]:
         """ GETs some json from the given host homeserver and path
 
         Args:
-            destination (str): The remote server to send the HTTP request
-                to.
+            destination: The remote server to send the HTTP request to.
 
-            path (str): The HTTP path.
+            path: The HTTP path.
 
-            args (dict|None): A dictionary used to create query strings, defaults to
+            args: A dictionary used to create query strings, defaults to
                 None.
 
-            timeout (int|None): number of milliseconds to wait for the response.
+            timeout: number of milliseconds to wait for the response.
                 self._default_timeout (60s) by default.
 
                 Note that we may make several attempts to send the request; this
@@ -822,14 +828,14 @@ class MatrixFederationHttpClient:
                 *each* attempt (including connection time) as well as the time spent
                 reading the response body after a 200 response.
 
-            ignore_backoff (bool): true to ignore the historical backoff data
+            ignore_backoff: true to ignore the historical backoff data
                 and try the request anyway.
 
-            try_trailing_slash_on_400 (bool): True if on a 400 M_UNRECOGNIZED
+            try_trailing_slash_on_400: True if on a 400 M_UNRECOGNIZED
                 response we should try appending a trailing slash to the end of
                 the request. Workaround for #3622 in Synapse <= v0.99.3.
         Returns:
-            dict|list: Succeeds when we get a 2xx HTTP response. The
+            Succeeds when we get a 2xx HTTP response. The
             result will be the decoded JSON body.
 
         Raises:
@@ -870,24 +876,23 @@ class MatrixFederationHttpClient:
 
     async def delete_json(
         self,
-        destination,
-        path,
-        long_retries=False,
-        timeout=None,
-        ignore_backoff=False,
-        args={},
-    ):
+        destination: str,
+        path: str,
+        long_retries: bool = False,
+        timeout: Optional[int] = None,
+        ignore_backoff: bool = False,
+        args: Optional[QueryArgs] = None,
+    ) -> Union[JsonDict, list]:
         """Send a DELETE request to the remote expecting some json response
 
         Args:
-            destination (str): The remote server to send the HTTP request
-                to.
-            path (str): The HTTP path.
+            destination: The remote server to send the HTTP request to.
+            path: The HTTP path.
 
-            long_retries (bool): whether to use the long retry algorithm. See
+            long_retries: whether to use the long retry algorithm. See
                 docs on _send_request for details.
 
-            timeout (int|None): number of milliseconds to wait for the response.
+            timeout: number of milliseconds to wait for the response.
                 self._default_timeout (60s) by default.
 
                 Note that we may make several attempts to send the request; this
@@ -895,12 +900,12 @@ class MatrixFederationHttpClient:
                 *each* attempt (including connection time) as well as the time spent
                 reading the response body after a 200 response.
 
-            ignore_backoff (bool): true to ignore the historical backoff data and
+            ignore_backoff: true to ignore the historical backoff data and
                 try the request anyway.
 
-            args (dict): query params
+            args: query params
         Returns:
-            dict|list: Succeeds when we get a 2xx HTTP response. The
+            Succeeds when we get a 2xx HTTP response. The
             result will be the decoded JSON body.
 
         Raises:
@@ -938,25 +943,25 @@ class MatrixFederationHttpClient:
 
     async def get_file(
         self,
-        destination,
-        path,
+        destination: str,
+        path: str,
         output_stream,
-        args={},
-        retry_on_dns_fail=True,
-        max_size=None,
-        ignore_backoff=False,
-    ):
+        args: Optional[QueryArgs] = None,
+        retry_on_dns_fail: bool = True,
+        max_size: Optional[int] = None,
+        ignore_backoff: bool = False,
+    ) -> Tuple[int, Dict[bytes, List[bytes]]]:
         """GETs a file from a given homeserver
         Args:
-            destination (str): The remote server to send the HTTP request to.
-            path (str): The HTTP path to GET.
-            output_stream (file): File to write the response body to.
-            args (dict): Optional dictionary used to create the query string.
-            ignore_backoff (bool): true to ignore the historical backoff data
+            destination: The remote server to send the HTTP request to.
+            path: The HTTP path to GET.
+            output_stream: File to write the response body to.
+            args: Optional dictionary used to create the query string.
+            ignore_backoff: true to ignore the historical backoff data
                 and try the request anyway.
 
         Returns:
-            tuple[int, dict]: Resolves with an (int,dict) tuple of
+            Resolves with an (int,dict) tuple of
             the file length and a dict of the response headers.
 
         Raises:
@@ -980,7 +985,7 @@ class MatrixFederationHttpClient:
         headers = dict(response.headers.getAllRawHeaders())
 
         try:
-            d = _readBodyToFile(response, output_stream, max_size)
+            d = readBodyToFile(response, output_stream, max_size)
             d.addTimeout(self.default_timeout, self.reactor)
             length = await make_deferred_yieldable(d)
         except Exception as e:
@@ -1004,40 +1009,6 @@ class MatrixFederationHttpClient:
         return (length, headers)
 
 
-class _ReadBodyToFileProtocol(protocol.Protocol):
-    def __init__(self, stream, deferred, max_size):
-        self.stream = stream
-        self.deferred = deferred
-        self.length = 0
-        self.max_size = max_size
-
-    def dataReceived(self, data):
-        self.stream.write(data)
-        self.length += len(data)
-        if self.max_size is not None and self.length >= self.max_size:
-            self.deferred.errback(
-                SynapseError(
-                    502,
-                    "Requested file is too large > %r bytes" % (self.max_size,),
-                    Codes.TOO_LARGE,
-                )
-            )
-            self.deferred = defer.Deferred()
-            self.transport.loseConnection()
-
-    def connectionLost(self, reason):
-        if reason.check(ResponseDone):
-            self.deferred.callback(self.length)
-        else:
-            self.deferred.errback(reason)
-
-
-def _readBodyToFile(response, stream, max_size):
-    d = defer.Deferred()
-    response.deliverBody(_ReadBodyToFileProtocol(stream, d, max_size))
-    return d
-
-
 def _flatten_response_never_received(e):
     if hasattr(e, "reasons"):
         reasons = ", ".join(
@@ -1049,13 +1020,13 @@ def _flatten_response_never_received(e):
         return repr(e)
 
 
-def check_content_type_is_json(headers):
+def check_content_type_is_json(headers: Headers) -> None:
     """
     Check that a set of HTTP headers have a Content-Type header, and that it
     is application/json.
 
     Args:
-        headers (twisted.web.http_headers.Headers): headers to check
+        headers: headers to check
 
     Raises:
         RequestSendFailed: if the Content-Type header is missing or isn't JSON
@@ -1063,27 +1034,18 @@ def check_content_type_is_json(headers):
     """
     c_type = headers.getRawHeaders(b"Content-Type")
     if c_type is None:
-        raise RequestSendFailed(RuntimeError("No Content-Type header"), can_retry=False)
+        raise RequestSendFailed(
+            RuntimeError("No Content-Type header received from remote server"),
+            can_retry=False,
+        )
 
     c_type = c_type[0].decode("ascii")  # only the first header
     val, options = cgi.parse_header(c_type)
     if val != "application/json":
         raise RequestSendFailed(
-            RuntimeError("Content-Type not application/json: was '%s'" % c_type),
+            RuntimeError(
+                "Remote server sent Content-Type header of '%s', not 'application/json'"
+                % c_type,
+            ),
             can_retry=False,
         )
-
-
-def encode_query_args(args):
-    if args is None:
-        return b""
-
-    encoded_args = {}
-    for k, vs in args.items():
-        if isinstance(vs, str):
-            vs = [vs]
-        encoded_args[k] = [v.encode("UTF-8") for v in vs]
-
-    query_bytes = urllib.parse.urlencode(encoded_args, True)
-
-    return query_bytes.encode("utf8")
diff --git a/synapse/http/request_metrics.py b/synapse/http/request_metrics.py
index cd94e789e8..7c5defec82 100644
--- a/synapse/http/request_metrics.py
+++ b/synapse/http/request_metrics.py
@@ -109,7 +109,7 @@ in_flight_requests_db_sched_duration = Counter(
 # The set of all in flight requests, set[RequestMetrics]
 _in_flight_requests = set()
 
-# Protects the _in_flight_requests set from concurrent accesss
+# Protects the _in_flight_requests set from concurrent access
 _in_flight_requests_lock = threading.Lock()
 
 
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 996a31a9ec..6a4e429a6c 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -25,7 +25,7 @@ from io import BytesIO
 from typing import Any, Callable, Dict, Iterator, List, Tuple, Union
 
 import jinja2
-from canonicaljson import iterencode_canonical_json, iterencode_pretty_printed_json
+from canonicaljson import iterencode_canonical_json
 from zope.interface import implementer
 
 from twisted.internet import defer, interfaces
@@ -35,8 +35,6 @@ from twisted.web.server import NOT_DONE_YET, Request
 from twisted.web.static import File, NoRangeStaticProducer
 from twisted.web.util import redirectTo
 
-import synapse.events
-import synapse.metrics
 from synapse.api.errors import (
     CodeMessageException,
     Codes,
@@ -96,11 +94,7 @@ def return_json_error(f: failure.Failure, request: SynapseRequest) -> None:
                 pass
     else:
         respond_with_json(
-            request,
-            error_code,
-            error_dict,
-            send_cors=True,
-            pretty_print=_request_user_agent_is_curl(request),
+            request, error_code, error_dict, send_cors=True,
         )
 
 
@@ -182,7 +176,7 @@ class HttpServer:
         """ Register a callback that gets fired if we receive a http request
         with the given method for a path that matches the given regex.
 
-        If the regex contains groups these gets passed to the calback via
+        If the regex contains groups these gets passed to the callback via
         an unpacked tuple.
 
         Args:
@@ -241,7 +235,7 @@ class _AsyncResource(resource.Resource, metaclass=abc.ABCMeta):
 
     async def _async_render(self, request: Request):
         """Delegates to `_async_render_<METHOD>` methods, or returns a 400 if
-        no appropriate method exists. Can be overriden in sub classes for
+        no appropriate method exists. Can be overridden in sub classes for
         different routing.
         """
         # Treat HEAD requests as GET requests.
@@ -257,7 +251,7 @@ class _AsyncResource(resource.Resource, metaclass=abc.ABCMeta):
             if isinstance(raw_callback_return, (defer.Deferred, types.CoroutineType)):
                 callback_return = await raw_callback_return
             else:
-                callback_return = raw_callback_return
+                callback_return = raw_callback_return  # type: ignore
 
             return callback_return
 
@@ -292,7 +286,6 @@ class DirectServeJsonResource(_AsyncResource):
             code,
             response_object,
             send_cors=True,
-            pretty_print=_request_user_agent_is_curl(request),
             canonical_json=self.canonical_json,
         )
 
@@ -386,7 +379,7 @@ class JsonResource(DirectServeJsonResource):
     async def _async_render(self, request):
         callback, servlet_classname, group_dict = self._get_handler_for_request(request)
 
-        # Make sure we have an appopriate name for this handler in prometheus
+        # Make sure we have an appropriate name for this handler in prometheus
         # (rather than the default of JsonResource).
         request.request_metrics.name = servlet_classname
 
@@ -406,7 +399,7 @@ class JsonResource(DirectServeJsonResource):
         if isinstance(raw_callback_return, (defer.Deferred, types.CoroutineType)):
             callback_return = await raw_callback_return
         else:
-            callback_return = raw_callback_return
+            callback_return = raw_callback_return  # type: ignore
 
         return callback_return
 
@@ -589,7 +582,6 @@ def respond_with_json(
     code: int,
     json_object: Any,
     send_cors: bool = False,
-    pretty_print: bool = False,
     canonical_json: bool = True,
 ):
     """Sends encoded JSON in response to the given request.
@@ -600,8 +592,6 @@ def respond_with_json(
         json_object: The object to serialize to JSON.
         send_cors: Whether to send Cross-Origin Resource Sharing headers
             https://fetch.spec.whatwg.org/#http-cors-protocol
-        pretty_print: Whether to include indentation and line-breaks in the
-            resulting JSON bytes.
         canonical_json: Whether to use the canonicaljson algorithm when encoding
             the JSON bytes.
 
@@ -617,13 +607,10 @@ def respond_with_json(
         )
         return None
 
-    if pretty_print:
-        encoder = iterencode_pretty_printed_json
+    if canonical_json:
+        encoder = iterencode_canonical_json
     else:
-        if canonical_json or synapse.events.USE_FROZEN_DICTS:
-            encoder = iterencode_canonical_json
-        else:
-            encoder = _encode_json_bytes
+        encoder = _encode_json_bytes
 
     request.setResponseCode(code)
     request.setHeader(b"Content-Type", b"application/json")
@@ -651,6 +638,11 @@ def respond_with_json_bytes(
     Returns:
         twisted.web.server.NOT_DONE_YET if the request is still active.
     """
+    if request._disconnected:
+        logger.warning(
+            "Not sending response to request %s, already disconnected.", request
+        )
+        return
 
     request.setResponseCode(code)
     request.setHeader(b"Content-Type", b"application/json")
@@ -682,7 +674,7 @@ def set_cors_headers(request: Request):
     )
     request.setHeader(
         b"Access-Control-Allow-Headers",
-        b"Origin, X-Requested-With, Content-Type, Accept, Authorization",
+        b"Origin, X-Requested-With, Content-Type, Accept, Authorization, Date",
     )
 
 
@@ -756,11 +748,3 @@ def finish_request(request: Request):
         request.finish()
     except RuntimeError as e:
         logger.info("Connection disconnected before response was written: %r", e)
-
-
-def _request_user_agent_is_curl(request: Request) -> bool:
-    user_agents = request.requestHeaders.getRawHeaders(b"User-Agent", default=[])
-    for user_agent in user_agents:
-        if b"curl" in user_agent:
-            return True
-    return False
diff --git a/synapse/http/servlet.py b/synapse/http/servlet.py
index fd90ba7828..b361b7cbaf 100644
--- a/synapse/http/servlet.py
+++ b/synapse/http/servlet.py
@@ -272,7 +272,6 @@ class RestServlet:
       on_PUT
       on_POST
       on_DELETE
-      on_OPTIONS
 
     Automatically handles turning CodeMessageExceptions thrown by these methods
     into the appropriate HTTP response.
@@ -283,7 +282,7 @@ class RestServlet:
         if hasattr(self, "PATTERNS"):
             patterns = self.PATTERNS
 
-            for method in ("GET", "PUT", "POST", "OPTIONS", "DELETE"):
+            for method in ("GET", "PUT", "POST", "DELETE"):
                 if hasattr(self, "on_%s" % (method,)):
                     servlet_classname = self.__class__.__name__
                     method_handler = getattr(self, "on_%s" % (method,))
diff --git a/synapse/http/site.py b/synapse/http/site.py
index 6e79b47828..5f0581dc3f 100644
--- a/synapse/http/site.py
+++ b/synapse/http/site.py
@@ -14,7 +14,7 @@
 import contextlib
 import logging
 import time
-from typing import Optional
+from typing import Optional, Union
 
 from twisted.python.failure import Failure
 from twisted.web.server import Request, Site
@@ -23,6 +23,7 @@ from synapse.config.server import ListenerConfig
 from synapse.http import redact_uri
 from synapse.http.request_metrics import RequestMetrics, requests_counter
 from synapse.logging.context import LoggingContext, PreserveLoggingContext
+from synapse.types import Requester
 
 logger = logging.getLogger(__name__)
 
@@ -54,9 +55,12 @@ class SynapseRequest(Request):
         Request.__init__(self, channel, *args, **kw)
         self.site = channel.site
         self._channel = channel  # this is used by the tests
-        self.authenticated_entity = None
         self.start_time = 0.0
 
+        # The requester, if authenticated. For federation requests this is the
+        # server name, for client requests this is the Requester object.
+        self.requester = None  # type: Optional[Union[Requester, str]]
+
         # we can't yet create the logcontext, as we don't know the method.
         self.logcontext = None  # type: Optional[LoggingContext]
 
@@ -109,8 +113,14 @@ class SynapseRequest(Request):
             method = self.method.decode("ascii")
         return method
 
-    def get_user_agent(self):
-        return self.requestHeaders.getRawHeaders(b"User-Agent", [None])[-1]
+    def get_user_agent(self, default: str) -> str:
+        """Return the last User-Agent header, or the given default.
+        """
+        user_agent = self.requestHeaders.getRawHeaders(b"User-Agent", [None])[-1]
+        if user_agent is None:
+            return default
+
+        return user_agent.decode("ascii", "replace")
 
     def render(self, resrc):
         # this is called once a Resource has been found to serve the request; in our
@@ -161,7 +171,9 @@ class SynapseRequest(Request):
             yield
         except Exception:
             # this should already have been caught, and sent back to the client as a 500.
-            logger.exception("Asynchronous messge handler raised an uncaught exception")
+            logger.exception(
+                "Asynchronous message handler raised an uncaught exception"
+            )
         finally:
             # the request handler has finished its work and either sent the whole response
             # back, or handed over responsibility to a Producer.
@@ -263,22 +275,30 @@ class SynapseRequest(Request):
         # to the client (nb may be negative)
         response_send_time = self.finish_time - self._processing_finished_time
 
-        # need to decode as it could be raw utf-8 bytes
-        # from a IDN servname in an auth header
-        authenticated_entity = self.authenticated_entity
-        if authenticated_entity is not None and isinstance(authenticated_entity, bytes):
-            authenticated_entity = authenticated_entity.decode("utf-8", "replace")
+        # Convert the requester into a string that we can log
+        authenticated_entity = None
+        if isinstance(self.requester, str):
+            authenticated_entity = self.requester
+        elif isinstance(self.requester, Requester):
+            authenticated_entity = self.requester.authenticated_entity
+
+            # If this is a request where the target user doesn't match the user who
+            # authenticated (e.g. and admin is puppetting a user) then we log both.
+            if self.requester.user.to_string() != authenticated_entity:
+                authenticated_entity = "{},{}".format(
+                    authenticated_entity, self.requester.user.to_string(),
+                )
+        elif self.requester is not None:
+            # This shouldn't happen, but we log it so we don't lose information
+            # and can see that we're doing something wrong.
+            authenticated_entity = repr(self.requester)  # type: ignore[unreachable]
 
         # ...or could be raw utf-8 bytes in the User-Agent header.
         # N.B. if you don't do this, the logger explodes cryptically
         # with maximum recursion trying to log errors about
         # the charset problem.
         # c.f. https://github.com/matrix-org/synapse/issues/3471
-        user_agent = self.get_user_agent()
-        if user_agent is not None:
-            user_agent = user_agent.decode("utf-8", "replace")
-        else:
-            user_agent = "-"
+        user_agent = self.get_user_agent("-")
 
         code = str(self.code)
         if not self.finished:
diff --git a/synapse/logging/__init__.py b/synapse/logging/__init__.py
index e69de29bb2..b28b7b2ef7 100644
--- a/synapse/logging/__init__.py
+++ b/synapse/logging/__init__.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# These are imported to allow for nicer logging configuration files.
+from synapse.logging._remote import RemoteHandler
+from synapse.logging._terse_json import JsonFormatter, TerseJsonFormatter
+
+__all__ = ["RemoteHandler", "JsonFormatter", "TerseJsonFormatter"]
diff --git a/synapse/logging/_remote.py b/synapse/logging/_remote.py
new file mode 100644
index 0000000000..fb937b3f28
--- /dev/null
+++ b/synapse/logging/_remote.py
@@ -0,0 +1,241 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+import sys
+import traceback
+from collections import deque
+from ipaddress import IPv4Address, IPv6Address, ip_address
+from math import floor
+from typing import Callable, Optional
+
+import attr
+from typing_extensions import Deque
+from zope.interface import implementer
+
+from twisted.application.internet import ClientService
+from twisted.internet.defer import CancelledError, Deferred
+from twisted.internet.endpoints import (
+    HostnameEndpoint,
+    TCP4ClientEndpoint,
+    TCP6ClientEndpoint,
+)
+from twisted.internet.interfaces import IPushProducer, ITransport
+from twisted.internet.protocol import Factory, Protocol
+from twisted.python.failure import Failure
+
+logger = logging.getLogger(__name__)
+
+
+@attr.s
+@implementer(IPushProducer)
+class LogProducer:
+    """
+    An IPushProducer that writes logs from its buffer to its transport when it
+    is resumed.
+
+    Args:
+        buffer: Log buffer to read logs from.
+        transport: Transport to write to.
+        format: A callable to format the log record to a string.
+    """
+
+    transport = attr.ib(type=ITransport)
+    _format = attr.ib(type=Callable[[logging.LogRecord], str])
+    _buffer = attr.ib(type=deque)
+    _paused = attr.ib(default=False, type=bool, init=False)
+
+    def pauseProducing(self):
+        self._paused = True
+
+    def stopProducing(self):
+        self._paused = True
+        self._buffer = deque()
+
+    def resumeProducing(self):
+        # If we're already producing, nothing to do.
+        self._paused = False
+
+        # Loop until paused.
+        while self._paused is False and (self._buffer and self.transport.connected):
+            try:
+                # Request the next record and format it.
+                record = self._buffer.popleft()
+                msg = self._format(record)
+
+                # Send it as a new line over the transport.
+                self.transport.write(msg.encode("utf8"))
+                self.transport.write(b"\n")
+            except Exception:
+                # Something has gone wrong writing to the transport -- log it
+                # and break out of the while.
+                traceback.print_exc(file=sys.__stderr__)
+                break
+
+
+class RemoteHandler(logging.Handler):
+    """
+    An logging handler that writes logs to a TCP target.
+
+    Args:
+        host: The host of the logging target.
+        port: The logging target's port.
+        maximum_buffer: The maximum buffer size.
+    """
+
+    def __init__(
+        self,
+        host: str,
+        port: int,
+        maximum_buffer: int = 1000,
+        level=logging.NOTSET,
+        _reactor=None,
+    ):
+        super().__init__(level=level)
+        self.host = host
+        self.port = port
+        self.maximum_buffer = maximum_buffer
+
+        self._buffer = deque()  # type: Deque[logging.LogRecord]
+        self._connection_waiter = None  # type: Optional[Deferred]
+        self._producer = None  # type: Optional[LogProducer]
+
+        # Connect without DNS lookups if it's a direct IP.
+        if _reactor is None:
+            from twisted.internet import reactor
+
+            _reactor = reactor
+
+        try:
+            ip = ip_address(self.host)
+            if isinstance(ip, IPv4Address):
+                endpoint = TCP4ClientEndpoint(_reactor, self.host, self.port)
+            elif isinstance(ip, IPv6Address):
+                endpoint = TCP6ClientEndpoint(_reactor, self.host, self.port)
+            else:
+                raise ValueError("Unknown IP address provided: %s" % (self.host,))
+        except ValueError:
+            endpoint = HostnameEndpoint(_reactor, self.host, self.port)
+
+        factory = Factory.forProtocol(Protocol)
+        self._service = ClientService(endpoint, factory, clock=_reactor)
+        self._service.startService()
+        self._stopping = False
+        self._connect()
+
+    def close(self):
+        self._stopping = True
+        self._service.stopService()
+
+    def _connect(self) -> None:
+        """
+        Triggers an attempt to connect then write to the remote if not already writing.
+        """
+        # Do not attempt to open multiple connections.
+        if self._connection_waiter:
+            return
+
+        self._connection_waiter = self._service.whenConnected(failAfterFailures=1)
+
+        def fail(failure: Failure) -> None:
+            # If the Deferred was cancelled (e.g. during shutdown) do not try to
+            # reconnect (this will cause an infinite loop of errors).
+            if failure.check(CancelledError) and self._stopping:
+                return
+
+            # For a different error, print the traceback and re-connect.
+            failure.printTraceback(file=sys.__stderr__)
+            self._connection_waiter = None
+            self._connect()
+
+        def writer(result: Protocol) -> None:
+            # We have a connection. If we already have a producer, and its
+            # transport is the same, just trigger a resumeProducing.
+            if self._producer and result.transport is self._producer.transport:
+                self._producer.resumeProducing()
+                self._connection_waiter = None
+                return
+
+            # If the producer is still producing, stop it.
+            if self._producer:
+                self._producer.stopProducing()
+
+            # Make a new producer and start it.
+            self._producer = LogProducer(
+                buffer=self._buffer, transport=result.transport, format=self.format,
+            )
+            result.transport.registerProducer(self._producer, True)
+            self._producer.resumeProducing()
+            self._connection_waiter = None
+
+        self._connection_waiter.addCallbacks(writer, fail)
+
+    def _handle_pressure(self) -> None:
+        """
+        Handle backpressure by shedding records.
+
+        The buffer will, in this order, until the buffer is below the maximum:
+            - Shed DEBUG records.
+            - Shed INFO records.
+            - Shed the middle 50% of the records.
+        """
+        if len(self._buffer) <= self.maximum_buffer:
+            return
+
+        # Strip out DEBUGs
+        self._buffer = deque(
+            filter(lambda record: record.levelno > logging.DEBUG, self._buffer)
+        )
+
+        if len(self._buffer) <= self.maximum_buffer:
+            return
+
+        # Strip out INFOs
+        self._buffer = deque(
+            filter(lambda record: record.levelno > logging.INFO, self._buffer)
+        )
+
+        if len(self._buffer) <= self.maximum_buffer:
+            return
+
+        # Cut the middle entries out
+        buffer_split = floor(self.maximum_buffer / 2)
+
+        old_buffer = self._buffer
+        self._buffer = deque()
+
+        for i in range(buffer_split):
+            self._buffer.append(old_buffer.popleft())
+
+        end_buffer = []
+        for i in range(buffer_split):
+            end_buffer.append(old_buffer.pop())
+
+        self._buffer.extend(reversed(end_buffer))
+
+    def emit(self, record: logging.LogRecord) -> None:
+        self._buffer.append(record)
+
+        # Handle backpressure, if it exists.
+        try:
+            self._handle_pressure()
+        except Exception:
+            # If handling backpressure fails, clear the buffer and log the
+            # exception.
+            self._buffer.clear()
+            logger.warning("Failed clearing backpressure")
+
+        # Try and write immediately.
+        self._connect()
diff --git a/synapse/logging/_structured.py b/synapse/logging/_structured.py
index 144506c8f2..14d9c104c2 100644
--- a/synapse/logging/_structured.py
+++ b/synapse/logging/_structured.py
@@ -12,146 +12,12 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
-import logging
 import os.path
-import sys
-import typing
-import warnings
-from typing import List
+from typing import Any, Dict, Generator, Optional, Tuple
 
-import attr
-from constantly import NamedConstant, Names, ValueConstant, Values
-from zope.interface import implementer
-
-from twisted.logger import (
-    FileLogObserver,
-    FilteringLogObserver,
-    ILogObserver,
-    LogBeginner,
-    Logger,
-    LogLevel,
-    LogLevelFilterPredicate,
-    LogPublisher,
-    eventAsText,
-    jsonFileLogObserver,
-)
+from constantly import NamedConstant, Names
 
 from synapse.config._base import ConfigError
-from synapse.logging._terse_json import (
-    TerseJSONToConsoleLogObserver,
-    TerseJSONToTCPLogObserver,
-)
-from synapse.logging.context import current_context
-
-
-def stdlib_log_level_to_twisted(level: str) -> LogLevel:
-    """
-    Convert a stdlib log level to Twisted's log level.
-    """
-    lvl = level.lower().replace("warning", "warn")
-    return LogLevel.levelWithName(lvl)
-
-
-@attr.s
-@implementer(ILogObserver)
-class LogContextObserver:
-    """
-    An ILogObserver which adds Synapse-specific log context information.
-
-    Attributes:
-        observer (ILogObserver): The target parent observer.
-    """
-
-    observer = attr.ib()
-
-    def __call__(self, event: dict) -> None:
-        """
-        Consume a log event and emit it to the parent observer after filtering
-        and adding log context information.
-
-        Args:
-            event (dict)
-        """
-        # Filter out some useless events that Twisted outputs
-        if "log_text" in event:
-            if event["log_text"].startswith("DNSDatagramProtocol starting on "):
-                return
-
-            if event["log_text"].startswith("(UDP Port "):
-                return
-
-            if event["log_text"].startswith("Timing out client") or event[
-                "log_format"
-            ].startswith("Timing out client"):
-                return
-
-        context = current_context()
-
-        # Copy the context information to the log event.
-        if context is not None:
-            context.copy_to_twisted_log_entry(event)
-        else:
-            # If there's no logging context, not even the root one, we might be
-            # starting up or it might be from non-Synapse code. Log it as if it
-            # came from the root logger.
-            event["request"] = None
-            event["scope"] = None
-
-        self.observer(event)
-
-
-class PythonStdlibToTwistedLogger(logging.Handler):
-    """
-    Transform a Python stdlib log message into a Twisted one.
-    """
-
-    def __init__(self, observer, *args, **kwargs):
-        """
-        Args:
-            observer (ILogObserver): A Twisted logging observer.
-            *args, **kwargs: Args/kwargs to be passed to logging.Handler.
-        """
-        self.observer = observer
-        super().__init__(*args, **kwargs)
-
-    def emit(self, record: logging.LogRecord) -> None:
-        """
-        Emit a record to Twisted's observer.
-
-        Args:
-            record (logging.LogRecord)
-        """
-
-        self.observer(
-            {
-                "log_time": record.created,
-                "log_text": record.getMessage(),
-                "log_format": "{log_text}",
-                "log_namespace": record.name,
-                "log_level": stdlib_log_level_to_twisted(record.levelname),
-            }
-        )
-
-
-def SynapseFileLogObserver(outFile: typing.IO[str]) -> FileLogObserver:
-    """
-    A log observer that formats events like the traditional log formatter and
-    sends them to `outFile`.
-
-    Args:
-        outFile (file object): The file object to write to.
-    """
-
-    def formatEvent(_event: dict) -> str:
-        event = dict(_event)
-        event["log_level"] = event["log_level"].name.upper()
-        event["log_format"] = "- {log_namespace} - {log_level} - {request} - " + (
-            event.get("log_format", "{log_text}") or "{log_text}"
-        )
-        return eventAsText(event, includeSystem=False) + "\n"
-
-    return FileLogObserver(outFile, formatEvent)
 
 
 class DrainType(Names):
@@ -163,30 +29,12 @@ class DrainType(Names):
     NETWORK_JSON_TERSE = NamedConstant()
 
 
-class OutputPipeType(Values):
-    stdout = ValueConstant(sys.__stdout__)
-    stderr = ValueConstant(sys.__stderr__)
-
-
-@attr.s
-class DrainConfiguration:
-    name = attr.ib()
-    type = attr.ib()
-    location = attr.ib()
-    options = attr.ib(default=None)
-
-
-@attr.s
-class NetworkJSONTerseOptions:
-    maximum_buffer = attr.ib(type=int)
-
-
-DEFAULT_LOGGERS = {"synapse": {"level": "INFO"}}
+DEFAULT_LOGGERS = {"synapse": {"level": "info"}}
 
 
 def parse_drain_configs(
     drains: dict,
-) -> typing.Generator[DrainConfiguration, None, None]:
+) -> Generator[Tuple[str, Dict[str, Any]], None, None]:
     """
     Parse the drain configurations.
 
@@ -194,11 +42,12 @@ def parse_drain_configs(
         drains (dict): A list of drain configurations.
 
     Yields:
-        DrainConfiguration instances.
+        dict instances representing a logging handler.
 
     Raises:
         ConfigError: If any of the drain configuration items are invalid.
     """
+
     for name, config in drains.items():
         if "type" not in config:
             raise ConfigError("Logging drains require a 'type' key.")
@@ -210,6 +59,18 @@ def parse_drain_configs(
                 "%s is not a known logging drain type." % (config["type"],)
             )
 
+        # Either use the default formatter or the tersejson one.
+        if logging_type in (DrainType.CONSOLE_JSON, DrainType.FILE_JSON,):
+            formatter = "json"  # type: Optional[str]
+        elif logging_type in (
+            DrainType.CONSOLE_JSON_TERSE,
+            DrainType.NETWORK_JSON_TERSE,
+        ):
+            formatter = "tersejson"
+        else:
+            # A formatter of None implies using the default formatter.
+            formatter = None
+
         if logging_type in [
             DrainType.CONSOLE,
             DrainType.CONSOLE_JSON,
@@ -225,9 +86,11 @@ def parse_drain_configs(
                     % (logging_type,)
                 )
 
-            pipe = OutputPipeType.lookupByName(location).value
-
-            yield DrainConfiguration(name=name, type=logging_type, location=pipe)
+            yield name, {
+                "class": "logging.StreamHandler",
+                "formatter": formatter,
+                "stream": "ext://sys." + location,
+            }
 
         elif logging_type in [DrainType.FILE, DrainType.FILE_JSON]:
             if "location" not in config:
@@ -241,18 +104,25 @@ def parse_drain_configs(
                     "File paths need to be absolute, '%s' is a relative path"
                     % (location,)
                 )
-            yield DrainConfiguration(name=name, type=logging_type, location=location)
+
+            yield name, {
+                "class": "logging.FileHandler",
+                "formatter": formatter,
+                "filename": location,
+            }
 
         elif logging_type in [DrainType.NETWORK_JSON_TERSE]:
             host = config.get("host")
             port = config.get("port")
             maximum_buffer = config.get("maximum_buffer", 1000)
-            yield DrainConfiguration(
-                name=name,
-                type=logging_type,
-                location=(host, port),
-                options=NetworkJSONTerseOptions(maximum_buffer=maximum_buffer),
-            )
+
+            yield name, {
+                "class": "synapse.logging.RemoteHandler",
+                "formatter": formatter,
+                "host": host,
+                "port": port,
+                "maximum_buffer": maximum_buffer,
+            }
 
         else:
             raise ConfigError(
@@ -261,126 +131,29 @@ def parse_drain_configs(
             )
 
 
-class StoppableLogPublisher(LogPublisher):
+def setup_structured_logging(log_config: dict,) -> dict:
     """
-    A log publisher that can tell its observers to shut down any external
-    communications.
+    Convert a legacy structured logging configuration (from Synapse < v1.23.0)
+    to one compatible with the new standard library handlers.
     """
-
-    def stop(self):
-        for obs in self._observers:
-            if hasattr(obs, "stop"):
-                obs.stop()
-
-
-def setup_structured_logging(
-    hs,
-    config,
-    log_config: dict,
-    logBeginner: LogBeginner,
-    redirect_stdlib_logging: bool = True,
-) -> LogPublisher:
-    """
-    Set up Twisted's structured logging system.
-
-    Args:
-        hs: The homeserver to use.
-        config (HomeserverConfig): The configuration of the Synapse homeserver.
-        log_config (dict): The log configuration to use.
-    """
-    if config.no_redirect_stdio:
-        raise ConfigError(
-            "no_redirect_stdio cannot be defined using structured logging."
-        )
-
-    logger = Logger()
-
     if "drains" not in log_config:
         raise ConfigError("The logging configuration requires a list of drains.")
 
-    observers = []  # type: List[ILogObserver]
+    new_config = {
+        "version": 1,
+        "formatters": {
+            "json": {"class": "synapse.logging.JsonFormatter"},
+            "tersejson": {"class": "synapse.logging.TerseJsonFormatter"},
+        },
+        "handlers": {},
+        "loggers": log_config.get("loggers", DEFAULT_LOGGERS),
+        "root": {"handlers": []},
+    }
 
-    for observer in parse_drain_configs(log_config["drains"]):
-        # Pipe drains
-        if observer.type == DrainType.CONSOLE:
-            logger.debug(
-                "Starting up the {name} console logger drain", name=observer.name
-            )
-            observers.append(SynapseFileLogObserver(observer.location))
-        elif observer.type == DrainType.CONSOLE_JSON:
-            logger.debug(
-                "Starting up the {name} JSON console logger drain", name=observer.name
-            )
-            observers.append(jsonFileLogObserver(observer.location))
-        elif observer.type == DrainType.CONSOLE_JSON_TERSE:
-            logger.debug(
-                "Starting up the {name} terse JSON console logger drain",
-                name=observer.name,
-            )
-            observers.append(
-                TerseJSONToConsoleLogObserver(observer.location, metadata={})
-            )
+    for handler_name, handler in parse_drain_configs(log_config["drains"]):
+        new_config["handlers"][handler_name] = handler
 
-        # File drains
-        elif observer.type == DrainType.FILE:
-            logger.debug("Starting up the {name} file logger drain", name=observer.name)
-            log_file = open(observer.location, "at", buffering=1, encoding="utf8")
-            observers.append(SynapseFileLogObserver(log_file))
-        elif observer.type == DrainType.FILE_JSON:
-            logger.debug(
-                "Starting up the {name} JSON file logger drain", name=observer.name
-            )
-            log_file = open(observer.location, "at", buffering=1, encoding="utf8")
-            observers.append(jsonFileLogObserver(log_file))
+        # Add each handler to the root logger.
+        new_config["root"]["handlers"].append(handler_name)
 
-        elif observer.type == DrainType.NETWORK_JSON_TERSE:
-            metadata = {"server_name": hs.config.server_name}
-            log_observer = TerseJSONToTCPLogObserver(
-                hs=hs,
-                host=observer.location[0],
-                port=observer.location[1],
-                metadata=metadata,
-                maximum_buffer=observer.options.maximum_buffer,
-            )
-            log_observer.start()
-            observers.append(log_observer)
-        else:
-            # We should never get here, but, just in case, throw an error.
-            raise ConfigError("%s drain type cannot be configured" % (observer.type,))
-
-    publisher = StoppableLogPublisher(*observers)
-    log_filter = LogLevelFilterPredicate()
-
-    for namespace, namespace_config in log_config.get(
-        "loggers", DEFAULT_LOGGERS
-    ).items():
-        # Set the log level for twisted.logger.Logger namespaces
-        log_filter.setLogLevelForNamespace(
-            namespace,
-            stdlib_log_level_to_twisted(namespace_config.get("level", "INFO")),
-        )
-
-        # Also set the log levels for the stdlib logger namespaces, to prevent
-        # them getting to PythonStdlibToTwistedLogger and having to be formatted
-        if "level" in namespace_config:
-            logging.getLogger(namespace).setLevel(namespace_config.get("level"))
-
-    f = FilteringLogObserver(publisher, [log_filter])
-    lco = LogContextObserver(f)
-
-    if redirect_stdlib_logging:
-        stuff_into_twisted = PythonStdlibToTwistedLogger(lco)
-        stdliblogger = logging.getLogger()
-        stdliblogger.addHandler(stuff_into_twisted)
-
-    # Always redirect standard I/O, otherwise other logging outputs might miss
-    # it.
-    logBeginner.beginLoggingTo([lco], redirectStandardIO=True)
-
-    return publisher
-
-
-def reload_structured_logging(*args, log_config=None) -> None:
-    warnings.warn(
-        "Currently the structured logging system can not be reloaded, doing nothing"
-    )
+    return new_config
diff --git a/synapse/logging/_terse_json.py b/synapse/logging/_terse_json.py
index 1b8916cfa2..2fbf5549a1 100644
--- a/synapse/logging/_terse_json.py
+++ b/synapse/logging/_terse_json.py
@@ -16,314 +16,65 @@
 """
 Log formatters that output terse JSON.
 """
-
 import json
-import sys
-import traceback
-from collections import deque
-from ipaddress import IPv4Address, IPv6Address, ip_address
-from math import floor
-from typing import IO, Optional
-
-import attr
-from zope.interface import implementer
-
-from twisted.application.internet import ClientService
-from twisted.internet.defer import Deferred
-from twisted.internet.endpoints import (
-    HostnameEndpoint,
-    TCP4ClientEndpoint,
-    TCP6ClientEndpoint,
-)
-from twisted.internet.interfaces import IPushProducer, ITransport
-from twisted.internet.protocol import Factory, Protocol
-from twisted.logger import FileLogObserver, ILogObserver, Logger
+import logging
 
 _encoder = json.JSONEncoder(ensure_ascii=False, separators=(",", ":"))
 
-
-def flatten_event(event: dict, metadata: dict, include_time: bool = False):
-    """
-    Flatten a Twisted logging event to an dictionary capable of being sent
-    as a log event to a logging aggregation system.
-
-    The format is vastly simplified and is not designed to be a "human readable
-    string" in the sense that traditional logs are. Instead, the structure is
-    optimised for searchability and filtering, with human-understandable log
-    keys.
-
-    Args:
-        event (dict): The Twisted logging event we are flattening.
-        metadata (dict): Additional data to include with each log message. This
-            can be information like the server name. Since the target log
-            consumer does not know who we are other than by host IP, this
-            allows us to forward through static information.
-        include_time (bool): Should we include the `time` key? If False, the
-            event time is stripped from the event.
-    """
-    new_event = {}
-
-    # If it's a failure, make the new event's log_failure be the traceback text.
-    if "log_failure" in event:
-        new_event["log_failure"] = event["log_failure"].getTraceback()
-
-    # If it's a warning, copy over a string representation of the warning.
-    if "warning" in event:
-        new_event["warning"] = str(event["warning"])
-
-    # Stdlib logging events have "log_text" as their human-readable portion,
-    # Twisted ones have "log_format". For now, include the log_format, so that
-    # context only given in the log format (e.g. what is being logged) is
-    # available.
-    if "log_text" in event:
-        new_event["log"] = event["log_text"]
-    else:
-        new_event["log"] = event["log_format"]
-
-    # We want to include the timestamp when forwarding over the network, but
-    # exclude it when we are writing to stdout. This is because the log ingester
-    # (e.g. logstash, fluentd) can add its own timestamp.
-    if include_time:
-        new_event["time"] = round(event["log_time"], 2)
-
-    # Convert the log level to a textual representation.
-    new_event["level"] = event["log_level"].name.upper()
-
-    # Ignore these keys, and do not transfer them over to the new log object.
-    # They are either useless (isError), transferred manually above (log_time,
-    # log_level, etc), or contain Python objects which are not useful for output
-    # (log_logger, log_source).
-    keys_to_delete = [
-        "isError",
-        "log_failure",
-        "log_format",
-        "log_level",
-        "log_logger",
-        "log_source",
-        "log_system",
-        "log_time",
-        "log_text",
-        "observer",
-        "warning",
-    ]
-
-    # If it's from the Twisted legacy logger (twisted.python.log), it adds some
-    # more keys we want to purge.
-    if event.get("log_namespace") == "log_legacy":
-        keys_to_delete.extend(["message", "system", "time"])
-
-    # Rather than modify the dictionary in place, construct a new one with only
-    # the content we want. The original event should be considered 'frozen'.
-    for key in event.keys():
-
-        if key in keys_to_delete:
-            continue
-
-        if isinstance(event[key], (str, int, bool, float)) or event[key] is None:
-            # If it's a plain type, include it as is.
-            new_event[key] = event[key]
-        else:
-            # If it's not one of those basic types, write out a string
-            # representation. This should probably be a warning in development,
-            # so that we are sure we are only outputting useful data.
-            new_event[key] = str(event[key])
-
-    # Add the metadata information to the event (e.g. the server_name).
-    new_event.update(metadata)
-
-    return new_event
+# The properties of a standard LogRecord.
+_LOG_RECORD_ATTRIBUTES = {
+    "args",
+    "asctime",
+    "created",
+    "exc_info",
+    # exc_text isn't a public attribute, but is used to cache the result of formatException.
+    "exc_text",
+    "filename",
+    "funcName",
+    "levelname",
+    "levelno",
+    "lineno",
+    "message",
+    "module",
+    "msecs",
+    "msg",
+    "name",
+    "pathname",
+    "process",
+    "processName",
+    "relativeCreated",
+    "stack_info",
+    "thread",
+    "threadName",
+}
 
 
-def TerseJSONToConsoleLogObserver(outFile: IO[str], metadata: dict) -> FileLogObserver:
-    """
-    A log observer that formats events to a flattened JSON representation.
+class JsonFormatter(logging.Formatter):
+    def format(self, record: logging.LogRecord) -> str:
+        event = {
+            "log": record.getMessage(),
+            "namespace": record.name,
+            "level": record.levelname,
+        }
 
-    Args:
-        outFile: The file object to write to.
-        metadata: Metadata to be added to each log object.
-    """
+        return self._format(record, event)
 
-    def formatEvent(_event: dict) -> str:
-        flattened = flatten_event(_event, metadata)
-        return _encoder.encode(flattened) + "\n"
+    def _format(self, record: logging.LogRecord, event: dict) -> str:
+        # Add any extra attributes to the event.
+        for key, value in record.__dict__.items():
+            if key not in _LOG_RECORD_ATTRIBUTES:
+                event[key] = value
 
-    return FileLogObserver(outFile, formatEvent)
+        return _encoder.encode(event)
 
 
-@attr.s
-@implementer(IPushProducer)
-class LogProducer:
-    """
-    An IPushProducer that writes logs from its buffer to its transport when it
-    is resumed.
+class TerseJsonFormatter(JsonFormatter):
+    def format(self, record: logging.LogRecord) -> str:
+        event = {
+            "log": record.getMessage(),
+            "namespace": record.name,
+            "level": record.levelname,
+            "time": round(record.created, 2),
+        }
 
-    Args:
-        buffer: Log buffer to read logs from.
-        transport: Transport to write to.
-    """
-
-    transport = attr.ib(type=ITransport)
-    _buffer = attr.ib(type=deque)
-    _paused = attr.ib(default=False, type=bool, init=False)
-
-    def pauseProducing(self):
-        self._paused = True
-
-    def stopProducing(self):
-        self._paused = True
-        self._buffer = deque()
-
-    def resumeProducing(self):
-        self._paused = False
-
-        while self._paused is False and (self._buffer and self.transport.connected):
-            try:
-                event = self._buffer.popleft()
-                self.transport.write(_encoder.encode(event).encode("utf8"))
-                self.transport.write(b"\n")
-            except Exception:
-                # Something has gone wrong writing to the transport -- log it
-                # and break out of the while.
-                traceback.print_exc(file=sys.__stderr__)
-                break
-
-
-@attr.s
-@implementer(ILogObserver)
-class TerseJSONToTCPLogObserver:
-    """
-    An IObserver that writes JSON logs to a TCP target.
-
-    Args:
-        hs (HomeServer): The homeserver that is being logged for.
-        host: The host of the logging target.
-        port: The logging target's port.
-        metadata: Metadata to be added to each log entry.
-    """
-
-    hs = attr.ib()
-    host = attr.ib(type=str)
-    port = attr.ib(type=int)
-    metadata = attr.ib(type=dict)
-    maximum_buffer = attr.ib(type=int)
-    _buffer = attr.ib(default=attr.Factory(deque), type=deque)
-    _connection_waiter = attr.ib(default=None, type=Optional[Deferred])
-    _logger = attr.ib(default=attr.Factory(Logger))
-    _producer = attr.ib(default=None, type=Optional[LogProducer])
-
-    def start(self) -> None:
-
-        # Connect without DNS lookups if it's a direct IP.
-        try:
-            ip = ip_address(self.host)
-            if isinstance(ip, IPv4Address):
-                endpoint = TCP4ClientEndpoint(
-                    self.hs.get_reactor(), self.host, self.port
-                )
-            elif isinstance(ip, IPv6Address):
-                endpoint = TCP6ClientEndpoint(
-                    self.hs.get_reactor(), self.host, self.port
-                )
-        except ValueError:
-            endpoint = HostnameEndpoint(self.hs.get_reactor(), self.host, self.port)
-
-        factory = Factory.forProtocol(Protocol)
-        self._service = ClientService(endpoint, factory, clock=self.hs.get_reactor())
-        self._service.startService()
-        self._connect()
-
-    def stop(self):
-        self._service.stopService()
-
-    def _connect(self) -> None:
-        """
-        Triggers an attempt to connect then write to the remote if not already writing.
-        """
-        if self._connection_waiter:
-            return
-
-        self._connection_waiter = self._service.whenConnected(failAfterFailures=1)
-
-        @self._connection_waiter.addErrback
-        def fail(r):
-            r.printTraceback(file=sys.__stderr__)
-            self._connection_waiter = None
-            self._connect()
-
-        @self._connection_waiter.addCallback
-        def writer(r):
-            # We have a connection. If we already have a producer, and its
-            # transport is the same, just trigger a resumeProducing.
-            if self._producer and r.transport is self._producer.transport:
-                self._producer.resumeProducing()
-                self._connection_waiter = None
-                return
-
-            # If the producer is still producing, stop it.
-            if self._producer:
-                self._producer.stopProducing()
-
-            # Make a new producer and start it.
-            self._producer = LogProducer(buffer=self._buffer, transport=r.transport)
-            r.transport.registerProducer(self._producer, True)
-            self._producer.resumeProducing()
-            self._connection_waiter = None
-
-    def _handle_pressure(self) -> None:
-        """
-        Handle backpressure by shedding events.
-
-        The buffer will, in this order, until the buffer is below the maximum:
-            - Shed DEBUG events
-            - Shed INFO events
-            - Shed the middle 50% of the events.
-        """
-        if len(self._buffer) <= self.maximum_buffer:
-            return
-
-        # Strip out DEBUGs
-        self._buffer = deque(
-            filter(lambda event: event["level"] != "DEBUG", self._buffer)
-        )
-
-        if len(self._buffer) <= self.maximum_buffer:
-            return
-
-        # Strip out INFOs
-        self._buffer = deque(
-            filter(lambda event: event["level"] != "INFO", self._buffer)
-        )
-
-        if len(self._buffer) <= self.maximum_buffer:
-            return
-
-        # Cut the middle entries out
-        buffer_split = floor(self.maximum_buffer / 2)
-
-        old_buffer = self._buffer
-        self._buffer = deque()
-
-        for i in range(buffer_split):
-            self._buffer.append(old_buffer.popleft())
-
-        end_buffer = []
-        for i in range(buffer_split):
-            end_buffer.append(old_buffer.pop())
-
-        self._buffer.extend(reversed(end_buffer))
-
-    def __call__(self, event: dict) -> None:
-        flattened = flatten_event(event, self.metadata, include_time=True)
-        self._buffer.append(flattened)
-
-        # Handle backpressure, if it exists.
-        try:
-            self._handle_pressure()
-        except Exception:
-            # If handling backpressure fails,clear the buffer and log the
-            # exception.
-            self._buffer.clear()
-            self._logger.failure("Failed clearing backpressure")
-
-        # Try and write immediately.
-        self._connect()
+        return self._format(record, event)
diff --git a/synapse/logging/filter.py b/synapse/logging/filter.py
new file mode 100644
index 0000000000..1baf8dd679
--- /dev/null
+++ b/synapse/logging/filter.py
@@ -0,0 +1,33 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+
+from typing_extensions import Literal
+
+
+class MetadataFilter(logging.Filter):
+    """Logging filter that adds constant values to each record.
+
+    Args:
+        metadata: Key-value pairs to add to each record.
+    """
+
+    def __init__(self, metadata: dict):
+        self._metadata = metadata
+
+    def filter(self, record: logging.LogRecord) -> Literal[True]:
+        for key, value in self._metadata.items():
+            setattr(record, key, value)
+        return True
diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py
index e58850faff..ab586c318c 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -317,7 +317,7 @@ def ensure_active_span(message, ret=None):
 
 
 @contextlib.contextmanager
-def _noop_context_manager(*args, **kwargs):
+def noop_context_manager(*args, **kwargs):
     """Does exactly what it says on the tin"""
     yield
 
@@ -413,7 +413,7 @@ def start_active_span(
     """
 
     if opentracing is None:
-        return _noop_context_manager()
+        return noop_context_manager()
 
     return opentracing.tracer.start_active_span(
         operation_name,
@@ -428,7 +428,7 @@ def start_active_span(
 
 def start_active_span_follows_from(operation_name, contexts):
     if opentracing is None:
-        return _noop_context_manager()
+        return noop_context_manager()
 
     references = [opentracing.follows_from(context) for context in contexts]
     scope = start_active_span(operation_name, references=references)
@@ -459,7 +459,7 @@ def start_active_span_from_request(
     # Also, twisted uses byte arrays while opentracing expects strings.
 
     if opentracing is None:
-        return _noop_context_manager()
+        return noop_context_manager()
 
     header_dict = {
         k.decode(): v[0].decode() for k, v in request.requestHeaders.getAllRawHeaders()
@@ -497,7 +497,7 @@ def start_active_span_from_edu(
     """
 
     if opentracing is None:
-        return _noop_context_manager()
+        return noop_context_manager()
 
     carrier = json_decoder.decode(edu_content.get("context", "{}")).get(
         "opentracing", {}
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index b8d2a8e8a9..cbf0dbb871 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -502,6 +502,16 @@ build_info.labels(
 
 last_ticked = time.time()
 
+# 3PID send info
+threepid_send_requests = Histogram(
+    "synapse_threepid_send_requests_with_tries",
+    documentation="Number of requests for a 3pid token by try count. Note if"
+    " there is a request with try count of 4, then there would have been one"
+    " each for 1, 2 and 3",
+    buckets=(1, 2, 3, 4, 5, 10),
+    labelnames=("type", "reason"),
+)
+
 
 class ReactorLastSeenMetric:
     def collect(self):
diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py
index 5b73463504..658f6ecd72 100644
--- a/synapse/metrics/background_process_metrics.py
+++ b/synapse/metrics/background_process_metrics.py
@@ -24,6 +24,7 @@ from prometheus_client.core import REGISTRY, Counter, Gauge
 from twisted.internet import defer
 
 from synapse.logging.context import LoggingContext, PreserveLoggingContext
+from synapse.logging.opentracing import noop_context_manager, start_active_span
 
 if TYPE_CHECKING:
     import resource
@@ -166,7 +167,7 @@ class _BackgroundProcess:
         )
 
 
-def run_as_background_process(desc: str, func, *args, **kwargs):
+def run_as_background_process(desc: str, func, *args, bg_start_span=True, **kwargs):
     """Run the given function in its own logcontext, with resource metrics
 
     This should be used to wrap processes which are fired off to run in the
@@ -180,6 +181,9 @@ def run_as_background_process(desc: str, func, *args, **kwargs):
     Args:
         desc: a description for this background process type
         func: a function, which may return a Deferred or a coroutine
+        bg_start_span: Whether to start an opentracing span. Defaults to True.
+            Should only be disabled for processes that will not log to or tag
+            a span.
         args: positional args for func
         kwargs: keyword args for func
 
@@ -197,14 +201,17 @@ def run_as_background_process(desc: str, func, *args, **kwargs):
 
         with BackgroundProcessLoggingContext(desc) as context:
             context.request = "%s-%i" % (desc, count)
-
             try:
-                result = func(*args, **kwargs)
+                ctx = noop_context_manager()
+                if bg_start_span:
+                    ctx = start_active_span(desc, tags={"request_id": context.request})
+                with ctx:
+                    result = func(*args, **kwargs)
 
-                if inspect.isawaitable(result):
-                    result = await result
+                    if inspect.isawaitable(result):
+                        result = await result
 
-                return result
+                    return result
             except Exception:
                 logger.exception(
                     "Background process '%s' threw an exception", desc,
@@ -265,7 +272,7 @@ class BackgroundProcessLoggingContext(LoggingContext):
 
         super().__exit__(type, value, traceback)
 
-        # The background process has finished. We explictly remove and manually
+        # The background process has finished. We explicitly remove and manually
         # update the metrics here so that if nothing is scraping metrics the set
         # doesn't infinitely grow.
         with _bg_metrics_lock:
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index 16ca86b7bc..72ab5750cc 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Iterable, Optional, Tuple
 
 from twisted.internet import defer
 
@@ -22,6 +22,7 @@ from synapse.events import EventBase
 from synapse.http.client import SimpleHttpClient
 from synapse.http.site import SynapseRequest
 from synapse.logging.context import make_deferred_yieldable, run_in_background
+from synapse.storage.state import StateFilter
 from synapse.types import JsonDict, UserID, create_requester
 
 if TYPE_CHECKING:
@@ -37,50 +38,6 @@ __all__ = ["errors", "make_deferred_yieldable", "run_in_background", "ModuleApi"
 logger = logging.getLogger(__name__)
 
 
-class PublicRoomListManager:
-    """Contains methods for adding to, removing from and querying whether a room
-    is in the public room list.
-
-    Args:
-        hs: The Homeserver object
-    """
-
-    def __init__(self, hs: "HomeServer"):
-        self._store = hs.get_datastore()
-
-    async def room_is_in_public_room_list(self, room_id: str) -> bool:
-        """Checks whether a room is in the public room list.
-
-        Args:
-            room_id: The ID of the room.
-
-        Returns:
-            Whether the room is in the public room list. Returns False if the room does
-            not exist.
-        """
-        room = await self._store.get_room(room_id)
-        if not room:
-            return False
-
-        return room.get("is_public", False)
-
-    async def add_room_to_public_room_list(self, room_id: str) -> None:
-        """Publishes a room to the public room list.
-
-        Args:
-            room_id: The ID of the room.
-        """
-        await self._store.set_room_is_public(room_id, True)
-
-    async def remove_room_from_public_room_list(self, room_id: str) -> None:
-        """Removes a room from the public room list.
-
-        Args:
-            room_id: The ID of the room.
-        """
-        await self._store.set_room_is_public(room_id, False)
-
-
 class ModuleApi:
     """A proxy object that gets passed to various plugin modules so they
     can register new users etc if necessary.
@@ -92,9 +49,28 @@ class ModuleApi:
         self._store = hs.get_datastore()
         self._auth = hs.get_auth()
         self._auth_handler = auth_handler
+        self._server_name = hs.hostname
 
-        self.http_client = hs.get_simple_http_client()  # type: SimpleHttpClient
-        self.public_room_list_manager = PublicRoomListManager(hs)
+        # We expose these as properties below in order to attach a helpful docstring.
+        self._http_client = hs.get_simple_http_client()  # type: SimpleHttpClient
+        self._public_room_list_manager = PublicRoomListManager(hs)
+
+    @property
+    def http_client(self):
+        """Allows making outbound HTTP requests to remote resources.
+
+        An instance of synapse.http.client.SimpleHttpClient
+        """
+        return self._http_client
+
+    @property
+    def public_room_list_manager(self):
+        """Allows adding to, removing from and checking the status of rooms in the
+        public room list.
+
+        An instance of synapse.module_api.PublicRoomListManager
+        """
+        return self._public_room_list_manager
 
     def get_user_by_req(self, req, allow_guest=False):
         """Check the access_token provided for a request
@@ -320,6 +296,32 @@ class ModuleApi:
             registered_user_id, request, client_redirect_url,
         )
 
+    @defer.inlineCallbacks
+    def get_state_events_in_room(
+        self, room_id: str, types: Iterable[Tuple[str, Optional[str]]]
+    ) -> defer.Deferred:
+        """Gets current state events for the given room.
+
+        (This is exposed for compatibility with the old SpamCheckerApi. We should
+        probably deprecate it and replace it with an async method in a subclass.)
+
+        Args:
+            room_id: The room ID to get state events in.
+            types: The event type and state key (using None
+                to represent 'any') of the room state to acquire.
+
+        Returns:
+            twisted.internet.defer.Deferred[list(synapse.events.FrozenEvent)]:
+                The filtered state events in the room.
+        """
+        state_ids = yield defer.ensureDeferred(
+            self._store.get_filtered_current_state_ids(
+                room_id=room_id, state_filter=StateFilter.from_types(types)
+            )
+        )
+        state = yield defer.ensureDeferred(self._store.get_events(state_ids.values()))
+        return state.values()
+
     async def create_and_send_event_into_room(self, event_dict: JsonDict) -> EventBase:
         """Create and send an event into a room. Membership events are currently not supported.
 
@@ -335,14 +337,57 @@ class ModuleApi:
             SynapseError if the event was not allowed.
         """
         # Create a requester object
-        requester = create_requester(event_dict["sender"])
+        requester = create_requester(
+            event_dict["sender"], authenticated_entity=self._server_name
+        )
 
         # Create and send the event
         (
             event,
             _,
         ) = await self._hs.get_event_creation_handler().create_and_send_nonmember_event(
-            requester, event_dict, ratelimit=False
+            requester, event_dict, ratelimit=False, ignore_shadow_ban=True,
         )
 
         return event
+
+
+class PublicRoomListManager:
+    """Contains methods for adding to, removing from and querying whether a room
+    is in the public room list.
+    """
+
+    def __init__(self, hs: "HomeServer"):
+        self._store = hs.get_datastore()
+
+    async def room_is_in_public_room_list(self, room_id: str) -> bool:
+        """Checks whether a room is in the public room list.
+
+        Args:
+            room_id: The ID of the room.
+
+        Returns:
+            Whether the room is in the public room list. Returns False if the room does
+            not exist.
+        """
+        room = await self._store.get_room(room_id)
+        if not room:
+            return False
+
+        return room.get("is_public", False)
+
+    async def add_room_to_public_room_list(self, room_id: str) -> None:
+        """Publishes a room to the public room list.
+
+        Args:
+            room_id: The ID of the room.
+        """
+        await self._store.set_room_is_public(room_id, True)
+
+    async def remove_room_from_public_room_list(self, room_id: str) -> None:
+        """Removes a room from the public room list.
+
+        Args:
+            room_id: The ID of the room.
+        """
+        await self._store.set_room_is_public(room_id, False)
diff --git a/synapse/notifier.py b/synapse/notifier.py
index 59415f6f88..a17352ef46 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -28,6 +28,7 @@ from typing import (
     Union,
 )
 
+import attr
 from prometheus_client import Counter
 
 from twisted.internet import defer
@@ -40,7 +41,6 @@ from synapse.handlers.presence import format_user_presence_state
 from synapse.logging.context import PreserveLoggingContext
 from synapse.logging.utils import log_function
 from synapse.metrics import LaterGauge
-from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.streams.config import PaginationConfig
 from synapse.types import (
     Collection,
@@ -174,6 +174,17 @@ class EventStreamResult(namedtuple("EventStreamResult", ("events", "tokens"))):
         return bool(self.events)
 
 
+@attr.s(slots=True, frozen=True)
+class _PendingRoomEventEntry:
+    event_pos = attr.ib(type=PersistedEventPosition)
+    extra_users = attr.ib(type=Collection[UserID])
+
+    room_id = attr.ib(type=str)
+    type = attr.ib(type=str)
+    state_key = attr.ib(type=Optional[str])
+    membership = attr.ib(type=Optional[str])
+
+
 class Notifier:
     """ This class is responsible for notifying any listeners when there are
     new events available for it.
@@ -191,9 +202,7 @@ class Notifier:
         self.storage = hs.get_storage()
         self.event_sources = hs.get_event_sources()
         self.store = hs.get_datastore()
-        self.pending_new_room_events = (
-            []
-        )  # type: List[Tuple[PersistedEventPosition, EventBase, Collection[UserID]]]
+        self.pending_new_room_events = []  # type: List[_PendingRoomEventEntry]
 
         # Called when there are new things to stream over replication
         self.replication_callbacks = []  # type: List[Callable[[], None]]
@@ -256,7 +265,29 @@ class Notifier:
         max_room_stream_token: RoomStreamToken,
         extra_users: Collection[UserID] = [],
     ):
-        """ Used by handlers to inform the notifier something has happened
+        """Unwraps event and calls `on_new_room_event_args`.
+        """
+        self.on_new_room_event_args(
+            event_pos=event_pos,
+            room_id=event.room_id,
+            event_type=event.type,
+            state_key=event.get("state_key"),
+            membership=event.content.get("membership"),
+            max_room_stream_token=max_room_stream_token,
+            extra_users=extra_users,
+        )
+
+    def on_new_room_event_args(
+        self,
+        room_id: str,
+        event_type: str,
+        state_key: Optional[str],
+        membership: Optional[str],
+        event_pos: PersistedEventPosition,
+        max_room_stream_token: RoomStreamToken,
+        extra_users: Collection[UserID] = [],
+    ):
+        """Used by handlers to inform the notifier something has happened
         in the room, room event wise.
 
         This triggers the notifier to wake up any listeners that are
@@ -267,7 +298,16 @@ class Notifier:
         until all previous events have been persisted before notifying
         the client streams.
         """
-        self.pending_new_room_events.append((event_pos, event, extra_users))
+        self.pending_new_room_events.append(
+            _PendingRoomEventEntry(
+                event_pos=event_pos,
+                extra_users=extra_users,
+                room_id=room_id,
+                type=event_type,
+                state_key=state_key,
+                membership=membership,
+            )
+        )
         self._notify_pending_new_room_events(max_room_stream_token)
 
         self.notify_replication()
@@ -285,18 +325,19 @@ class Notifier:
         users = set()  # type: Set[UserID]
         rooms = set()  # type: Set[str]
 
-        for event_pos, event, extra_users in pending:
-            if event_pos.persisted_after(max_room_stream_token):
-                self.pending_new_room_events.append((event_pos, event, extra_users))
+        for entry in pending:
+            if entry.event_pos.persisted_after(max_room_stream_token):
+                self.pending_new_room_events.append(entry)
             else:
                 if (
-                    event.type == EventTypes.Member
-                    and event.membership == Membership.JOIN
+                    entry.type == EventTypes.Member
+                    and entry.membership == Membership.JOIN
+                    and entry.state_key
                 ):
-                    self._user_joined_room(event.state_key, event.room_id)
+                    self._user_joined_room(entry.state_key, entry.room_id)
 
-                users.update(extra_users)
-                rooms.add(event.room_id)
+                users.update(entry.extra_users)
+                rooms.add(entry.room_id)
 
         if users or rooms:
             self.on_new_event(
@@ -310,28 +351,37 @@ class Notifier:
         """
 
         # poke any interested application service.
-        run_as_background_process(
-            "_notify_app_services", self._notify_app_services, max_room_stream_token
-        )
-
-        run_as_background_process(
-            "_notify_pusher_pool", self._notify_pusher_pool, max_room_stream_token
-        )
+        self._notify_app_services(max_room_stream_token)
+        self._notify_pusher_pool(max_room_stream_token)
 
         if self.federation_sender:
-            self.federation_sender.notify_new_events(max_room_stream_token.stream)
+            self.federation_sender.notify_new_events(max_room_stream_token)
 
-    async def _notify_app_services(self, max_room_stream_token: RoomStreamToken):
+    def _notify_app_services(self, max_room_stream_token: RoomStreamToken):
         try:
-            await self.appservice_handler.notify_interested_services(
-                max_room_stream_token.stream
+            self.appservice_handler.notify_interested_services(max_room_stream_token)
+        except Exception:
+            logger.exception("Error notifying application services of event")
+
+    def _notify_app_services_ephemeral(
+        self,
+        stream_key: str,
+        new_token: Union[int, RoomStreamToken],
+        users: Collection[Union[str, UserID]] = [],
+    ):
+        try:
+            stream_token = None
+            if isinstance(new_token, int):
+                stream_token = new_token
+            self.appservice_handler.notify_interested_services_ephemeral(
+                stream_key, stream_token, users
             )
         except Exception:
             logger.exception("Error notifying application services of event")
 
-    async def _notify_pusher_pool(self, max_room_stream_token: RoomStreamToken):
+    def _notify_pusher_pool(self, max_room_stream_token: RoomStreamToken):
         try:
-            await self._pusher_pool.on_new_notifications(max_room_stream_token.stream)
+            self._pusher_pool.on_new_notifications(max_room_stream_token)
         except Exception:
             logger.exception("Error pusher pool of event")
 
@@ -339,7 +389,7 @@ class Notifier:
         self,
         stream_key: str,
         new_token: Union[int, RoomStreamToken],
-        users: Collection[UserID] = [],
+        users: Collection[Union[str, UserID]] = [],
         rooms: Collection[str] = [],
     ):
         """ Used to inform listeners that something has happened event wise.
@@ -367,8 +417,13 @@ class Notifier:
 
                 self.notify_replication()
 
+                # Notify appservices
+                self._notify_app_services_ephemeral(
+                    stream_key, new_token, users,
+                )
+
     def on_new_replication_data(self) -> None:
-        """Used to inform replication listeners that something has happend
+        """Used to inform replication listeners that something has happened
         without waking up any of the normal user event streams"""
         self.notify_replication()
 
diff --git a/synapse/push/baserules.py b/synapse/push/baserules.py
index 172af1a5a4..f5c6c977c7 100644
--- a/synapse/push/baserules.py
+++ b/synapse/push/baserules.py
@@ -37,7 +37,7 @@ def list_with_base_rules(rawrules, use_new_defaults=False):
     modified_base_rules = {r["rule_id"]: r for r in rawrules if r["priority_class"] < 0}
 
     # Remove the modified base rules from the list, They'll be added back
-    # in the default postions in the list.
+    # in the default positions in the list.
     rawrules = [r for r in rawrules if r["priority_class"] >= 0]
 
     # shove the server default rules for each kind onto the end of each
@@ -506,6 +506,30 @@ BASE_APPEND_UNDERRIDE_RULES = [
             {"set_tweak": "highlight", "value": False},
         ],
     },
+    {
+        "rule_id": "global/underride/.im.vector.jitsi",
+        "conditions": [
+            {
+                "kind": "event_match",
+                "key": "type",
+                "pattern": "im.vector.modular.widgets",
+                "_id": "_type_modular_widgets",
+            },
+            {
+                "kind": "event_match",
+                "key": "content.type",
+                "pattern": "jitsi",
+                "_id": "_content_type_jitsi",
+            },
+            {
+                "kind": "event_match",
+                "key": "state_key",
+                "pattern": "*",
+                "_id": "_is_state_event",
+            },
+        ],
+        "actions": ["notify", {"set_tweak": "highlight", "value": False}],
+    },
 ]
 
 
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index c440f2545c..82a72dc34f 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -15,8 +15,8 @@
 # limitations under the License.
 
 import logging
-from collections import namedtuple
 
+import attr
 from prometheus_client import Counter
 
 from synapse.api.constants import EventTypes, Membership, RelationTypes
@@ -26,7 +26,8 @@ from synapse.events.snapshot import EventContext
 from synapse.state import POWER_KEY
 from synapse.util.async_helpers import Linearizer
 from synapse.util.caches import register_cache
-from synapse.util.caches.descriptors import cached
+from synapse.util.caches.descriptors import lru_cache
+from synapse.util.caches.lrucache import LruCache
 
 from .push_rule_evaluator import PushRuleEvaluatorForEvent
 
@@ -120,7 +121,7 @@ class BulkPushRuleEvaluator:
             dict of user_id -> push_rules
         """
         room_id = event.room_id
-        rules_for_room = await self._get_rules_for_room(room_id)
+        rules_for_room = self._get_rules_for_room(room_id)
 
         rules_by_user = await rules_for_room.get_rules(event, context)
 
@@ -138,7 +139,7 @@ class BulkPushRuleEvaluator:
 
         return rules_by_user
 
-    @cached()
+    @lru_cache()
     def _get_rules_for_room(self, room_id):
         """Get the current RulesForRoom object for the given room id
 
@@ -275,12 +276,14 @@ class RulesForRoom:
     the entire cache for the room.
     """
 
-    def __init__(self, hs, room_id, rules_for_room_cache, room_push_rule_cache_metrics):
+    def __init__(
+        self, hs, room_id, rules_for_room_cache: LruCache, room_push_rule_cache_metrics
+    ):
         """
         Args:
             hs (HomeServer)
             room_id (str)
-            rules_for_room_cache(Cache): The cache object that caches these
+            rules_for_room_cache: The cache object that caches these
                 RoomsForUser objects.
             room_push_rule_cache_metrics (CacheMetric)
         """
@@ -390,12 +393,12 @@ class RulesForRoom:
                     continue
 
                 # If a user has left a room we remove their push rule. If they
-                # joined then we readd it later in _update_rules_with_member_event_ids
+                # joined then we re-add it later in _update_rules_with_member_event_ids
                 ret_rules_by_user.pop(user_id, None)
                 missing_member_event_ids[user_id] = event_id
 
             if missing_member_event_ids:
-                # If we have some memebr events we haven't seen, look them up
+                # If we have some member events we haven't seen, look them up
                 # and fetch push rules for them if appropriate.
                 logger.debug("Found new member events %r", missing_member_event_ids)
                 await self._update_rules_with_member_event_ids(
@@ -489,12 +492,20 @@ class RulesForRoom:
             self.state_group = state_group
 
 
-class _Invalidation(namedtuple("_Invalidation", ("cache", "room_id"))):
-    # We rely on _CacheContext implementing __eq__ and __hash__ sensibly,
-    # which namedtuple does for us (i.e. two _CacheContext are the same if
-    # their caches and keys match). This is important in particular to
-    # dedupe when we add callbacks to lru cache nodes, otherwise the number
-    # of callbacks would grow.
+@attr.attrs(slots=True, frozen=True)
+class _Invalidation:
+    # _Invalidation is passed as an `on_invalidate` callback to bulk_get_push_rules,
+    # which means that it it is stored on the bulk_get_push_rules cache entry. In order
+    # to ensure that we don't accumulate lots of redunant callbacks on the cache entry,
+    # we need to ensure that two _Invalidation objects are "equal" if they refer to the
+    # same `cache` and `room_id`.
+    #
+    # attrs provides suitable __hash__ and __eq__ methods, provided we remember to
+    # set `frozen=True`.
+
+    cache = attr.ib(type=LruCache)
+    room_id = attr.ib(type=str)
+
     def __call__(self):
         rules = self.cache.get(self.room_id, None, update_metrics=False)
         if rules:
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index 28bd8ab748..c6763971ee 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -18,6 +18,7 @@ import logging
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
 from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.types import RoomStreamToken
 
 logger = logging.getLogger(__name__)
 
@@ -91,7 +92,12 @@ class EmailPusher:
                 pass
             self.timed_call = None
 
-    def on_new_notifications(self, max_stream_ordering):
+    def on_new_notifications(self, max_token: RoomStreamToken):
+        # We just use the minimum stream ordering and ignore the vector clock
+        # component. This is safe to do as long as we *always* ignore the vector
+        # clock components.
+        max_stream_ordering = max_token.stream
+
         if self.max_stream_ordering:
             self.max_stream_ordering = max(
                 max_stream_ordering, self.max_stream_ordering
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index 26706bf3e1..eff0975b6a 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -23,6 +23,7 @@ from synapse.api.constants import EventTypes
 from synapse.logging import opentracing
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.push import PusherConfigException
+from synapse.types import RoomStreamToken
 
 from . import push_rule_evaluator, push_tools
 
@@ -74,6 +75,7 @@ class HttpPusher:
         self.failing_since = pusherdict["failing_since"]
         self.timed_call = None
         self._is_processing = False
+        self._group_unread_count_by_room = hs.config.push_group_unread_count_by_room
 
         # This is the highest stream ordering we know it's safe to process.
         # When new events arrive, we'll be given a window of new events: we
@@ -114,7 +116,12 @@ class HttpPusher:
         if should_check_for_notifs:
             self._start_processing()
 
-    def on_new_notifications(self, max_stream_ordering):
+    def on_new_notifications(self, max_token: RoomStreamToken):
+        # We just use the minimum stream ordering and ignore the vector clock
+        # component. This is safe to do as long as we *always* ignore the vector
+        # clock components.
+        max_stream_ordering = max_token.stream
+
         self.max_stream_ordering = max(
             max_stream_ordering, self.max_stream_ordering or 0
         )
@@ -130,7 +137,11 @@ class HttpPusher:
     async def _update_badge(self):
         # XXX as per https://github.com/matrix-org/matrix-doc/issues/2627, this seems
         # to be largely redundant. perhaps we can remove it.
-        badge = await push_tools.get_badge_count(self.hs.get_datastore(), self.user_id)
+        badge = await push_tools.get_badge_count(
+            self.hs.get_datastore(),
+            self.user_id,
+            group_by_room=self._group_unread_count_by_room,
+        )
         await self._send_badge(badge)
 
     def on_timer(self):
@@ -277,7 +288,11 @@ class HttpPusher:
             return True
 
         tweaks = push_rule_evaluator.tweaks_for_actions(push_action["actions"])
-        badge = await push_tools.get_badge_count(self.hs.get_datastore(), self.user_id)
+        badge = await push_tools.get_badge_count(
+            self.hs.get_datastore(),
+            self.user_id,
+            group_by_room=self._group_unread_count_by_room,
+        )
 
         event = await self.store.get_event(push_action["event_id"], allow_none=True)
         if event is None:
diff --git a/synapse/push/mailer.py b/synapse/push/mailer.py
index 455a1acb46..38195c8eea 100644
--- a/synapse/push/mailer.py
+++ b/synapse/push/mailer.py
@@ -24,7 +24,7 @@ from typing import Iterable, List, TypeVar
 import bleach
 import jinja2
 
-from synapse.api.constants import EventTypes
+from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import StoreError
 from synapse.config.emailconfig import EmailSubjectConfig
 from synapse.logging.context import make_deferred_yieldable
@@ -317,9 +317,14 @@ class Mailer:
     async def get_room_vars(
         self, room_id, user_id, notifs, notif_events, room_state_ids
     ):
-        my_member_event_id = room_state_ids[("m.room.member", user_id)]
-        my_member_event = await self.store.get_event(my_member_event_id)
-        is_invite = my_member_event.content["membership"] == "invite"
+        # Check if one of the notifs is an invite event for the user.
+        is_invite = False
+        for n in notifs:
+            ev = notif_events[n["event_id"]]
+            if ev.type == EventTypes.Member and ev.state_key == user_id:
+                if ev.content.get("membership") == Membership.INVITE:
+                    is_invite = True
+                    break
 
         room_name = await calculate_room_name(self.store, room_state_ids, user_id)
 
@@ -387,8 +392,8 @@ class Mailer:
         return ret
 
     async def get_message_vars(self, notif, event, room_state_ids):
-        if event.type != EventTypes.Message:
-            return
+        if event.type != EventTypes.Message and event.type != EventTypes.Encrypted:
+            return None
 
         sender_state_event_id = room_state_ids[("m.room.member", event.sender)]
         sender_state_event = await self.store.get_event(sender_state_event_id)
@@ -399,10 +404,8 @@ class Mailer:
         # sender_hash % the number of default images to choose from
         sender_hash = string_ordinal_total(event.sender)
 
-        msgtype = event.content.get("msgtype")
-
         ret = {
-            "msgtype": msgtype,
+            "event_type": event.type,
             "is_historical": event.event_id != notif["event_id"],
             "id": event.event_id,
             "ts": event.origin_server_ts,
@@ -411,6 +414,14 @@ class Mailer:
             "sender_hash": sender_hash,
         }
 
+        # Encrypted messages don't have any additional useful information.
+        if event.type == EventTypes.Encrypted:
+            return ret
+
+        msgtype = event.content.get("msgtype")
+
+        ret["msgtype"] = msgtype
+
         if msgtype == "m.text":
             self.add_text_message_vars(ret, event)
         elif msgtype == "m.image":
@@ -455,16 +466,26 @@ class Mailer:
                 self.store, room_state_ids[room_id], user_id, fallback_to_members=False
             )
 
-            my_member_event_id = room_state_ids[room_id][("m.room.member", user_id)]
-            my_member_event = await self.store.get_event(my_member_event_id)
-            if my_member_event.content["membership"] == "invite":
-                inviter_member_event_id = room_state_ids[room_id][
-                    ("m.room.member", my_member_event.sender)
-                ]
-                inviter_member_event = await self.store.get_event(
-                    inviter_member_event_id
+            # See if one of the notifs is an invite event for the user
+            invite_event = None
+            for n in notifs_by_room[room_id]:
+                ev = notif_events[n["event_id"]]
+                if ev.type == EventTypes.Member and ev.state_key == user_id:
+                    if ev.content.get("membership") == Membership.INVITE:
+                        invite_event = ev
+                        break
+
+            if invite_event:
+                inviter_member_event_id = room_state_ids[room_id].get(
+                    ("m.room.member", invite_event.sender)
                 )
-                inviter_name = name_from_member_event(inviter_member_event)
+                inviter_name = invite_event.sender
+                if inviter_member_event_id:
+                    inviter_member_event = await self.store.get_event(
+                        inviter_member_event_id, allow_none=True
+                    )
+                    if inviter_member_event:
+                        inviter_name = name_from_member_event(inviter_member_event)
 
                 if room_name is None:
                     return self.email_subjects.invite_from_person % {
diff --git a/synapse/push/push_rule_evaluator.py b/synapse/push/push_rule_evaluator.py
index 709ace01e5..2ce9e444ab 100644
--- a/synapse/push/push_rule_evaluator.py
+++ b/synapse/push/push_rule_evaluator.py
@@ -16,11 +16,10 @@
 
 import logging
 import re
-from typing import Any, Dict, List, Pattern, Union
+from typing import Any, Dict, List, Optional, Pattern, Tuple, Union
 
 from synapse.events import EventBase
 from synapse.types import UserID
-from synapse.util.caches import register_cache
 from synapse.util.caches.lrucache import LruCache
 
 logger = logging.getLogger(__name__)
@@ -174,20 +173,21 @@ class PushRuleEvaluatorForEvent:
         # Similar to _glob_matches, but do not treat display_name as a glob.
         r = regex_cache.get((display_name, False, True), None)
         if not r:
-            r = re.escape(display_name)
-            r = _re_word_boundary(r)
-            r = re.compile(r, flags=re.IGNORECASE)
+            r1 = re.escape(display_name)
+            r1 = _re_word_boundary(r1)
+            r = re.compile(r1, flags=re.IGNORECASE)
             regex_cache[(display_name, False, True)] = r
 
-        return r.search(body)
+        return bool(r.search(body))
 
-    def _get_value(self, dotted_key: str) -> str:
+    def _get_value(self, dotted_key: str) -> Optional[str]:
         return self._value_cache.get(dotted_key, None)
 
 
 # Caches (string, is_glob, word_boundary) -> regex for push. See _glob_matches
-regex_cache = LruCache(50000)
-register_cache("cache", "regex_push_cache", regex_cache)
+regex_cache = LruCache(
+    50000, "regex_push_cache"
+)  # type: LruCache[Tuple[str, bool, bool], Pattern]
 
 
 def _glob_matches(glob: str, value: str, word_boundary: bool = False) -> bool:
@@ -205,7 +205,7 @@ def _glob_matches(glob: str, value: str, word_boundary: bool = False) -> bool:
         if not r:
             r = _glob_to_re(glob, word_boundary)
             regex_cache[(glob, True, word_boundary)] = r
-        return r.search(value)
+        return bool(r.search(value))
     except re.error:
         logger.warning("Failed to parse glob to regex: %r", glob)
         return False
diff --git a/synapse/push/push_tools.py b/synapse/push/push_tools.py
index d0145666bf..6e7c880dc0 100644
--- a/synapse/push/push_tools.py
+++ b/synapse/push/push_tools.py
@@ -12,12 +12,12 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 from synapse.push.presentable_names import calculate_room_name, name_from_member_event
 from synapse.storage import Storage
+from synapse.storage.databases.main import DataStore
 
 
-async def get_badge_count(store, user_id):
+async def get_badge_count(store: DataStore, user_id: str, group_by_room: bool) -> int:
     invites = await store.get_invited_rooms_for_local_user(user_id)
     joins = await store.get_rooms_for_user(user_id)
 
@@ -34,9 +34,15 @@ async def get_badge_count(store, user_id):
                     room_id, user_id, last_unread_event_id
                 )
             )
-            # return one badge count per conversation, as count per
-            # message is so noisy as to be almost useless
-            badge += 1 if notifs["notify_count"] else 0
+            if notifs["notify_count"] == 0:
+                continue
+
+            if group_by_room:
+                # return one badge count per conversation
+                badge += 1
+            else:
+                # increment the badge count by the number of unread messages in the room
+                badge += notifs["notify_count"]
     return badge
 
 
diff --git a/synapse/push/pusherpool.py b/synapse/push/pusherpool.py
index c731317143..32794af6ca 100644
--- a/synapse/push/pusherpool.py
+++ b/synapse/push/pusherpool.py
@@ -19,11 +19,15 @@ from typing import TYPE_CHECKING, Dict, Union
 
 from prometheus_client import Gauge
 
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import (
+    run_as_background_process,
+    wrap_as_background_process,
+)
 from synapse.push import PusherConfigException
 from synapse.push.emailpusher import EmailPusher
 from synapse.push.httppusher import HttpPusher
 from synapse.push.pusher import PusherFactory
+from synapse.types import RoomStreamToken
 from synapse.util.async_helpers import concurrently_execute
 
 if TYPE_CHECKING:
@@ -186,15 +190,31 @@ class PusherPool:
                 )
                 await self.remove_pusher(p["app_id"], p["pushkey"], p["user_name"])
 
-    async def on_new_notifications(self, max_stream_id: int):
+    def on_new_notifications(self, max_token: RoomStreamToken):
         if not self.pushers:
             # nothing to do here.
             return
 
+        # We just use the minimum stream ordering and ignore the vector clock
+        # component. This is safe to do as long as we *always* ignore the vector
+        # clock components.
+        max_stream_id = max_token.stream
+
         if max_stream_id < self._last_room_stream_id_seen:
             # Nothing to do
             return
 
+        # We only start a new background process if necessary rather than
+        # optimistically (to cut down on overhead).
+        self._on_new_notifications(max_token)
+
+    @wrap_as_background_process("on_new_notifications")
+    async def _on_new_notifications(self, max_token: RoomStreamToken):
+        # We just use the minimum stream ordering and ignore the vector clock
+        # component. This is safe to do as long as we *always* ignore the vector
+        # clock components.
+        max_stream_id = max_token.stream
+
         prev_stream_id = self._last_room_stream_id_seen
         self._last_room_stream_id_seen = max_stream_id
 
@@ -214,7 +234,7 @@ class PusherPool:
 
                 if u in self.pushers:
                     for p in self.pushers[u].values():
-                        p.on_new_notifications(max_stream_id)
+                        p.on_new_notifications(max_token)
 
         except Exception:
             logger.exception("Exception in pusher on_new_notifications")
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 3e188cd4d6..8e5d3e3c52 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -40,6 +40,10 @@ logger = logging.getLogger(__name__)
 # Note that these both represent runtime dependencies (and the versions
 # installed are checked at runtime).
 #
+# Also note that we replicate these constraints in the Synapse Dockerfile while
+# pre-installing dependencies. If these constraints are updated here, the same
+# change should be made in the Dockerfile.
+#
 # [1] https://pip.pypa.io/en/stable/reference/pip_install/#requirement-specifiers.
 
 REQUIREMENTS = [
@@ -69,10 +73,7 @@ REQUIREMENTS = [
     "msgpack>=0.5.2",
     "phonenumbers>=8.2.0",
     # we use GaugeHistogramMetric, which was added in prom-client 0.4.0.
-    # prom-client has a history of breaking backwards compatibility between
-    # minor versions (https://github.com/prometheus/client_python/issues/317),
-    # so we also pin the minor version.
-    "prometheus_client>=0.4.0,<0.9.0",
+    "prometheus_client>=0.4.0",
     # we use attr.validators.deep_iterable, which arrived in 19.1.0 (Note:
     # Fedora 31 only has 19.1, so if we want to upgrade we should wait until 33
     # is out in November.)
@@ -95,7 +96,11 @@ CONDITIONAL_REQUIREMENTS = {
         # python 3.5.2, as per https://github.com/itamarst/eliot/issues/418
         'eliot<1.8.0;python_version<"3.5.3"',
     ],
-    "saml2": ["pysaml2>=4.5.0"],
+    "saml2": [
+        # pysaml2 6.4.0 is incompatible with Python 3.5 (see https://github.com/IdentityPython/pysaml2/issues/749)
+        "pysaml2>=4.5.0,<6.4.0;python_version<'3.6'",
+        "pysaml2>=4.5.0;python_version>='3.6'",
+    ],
     "oidc": ["authlib>=0.14.0"],
     "systemd": ["systemd-python>=231"],
     "url_preview": ["lxml>=3.5.0"],
diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index 64edadb624..2b3972cb14 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -92,7 +92,7 @@ class ReplicationEndpoint(metaclass=abc.ABCMeta):
         if self.CACHE:
             self.response_cache = ResponseCache(
                 hs, "repl." + self.NAME, timeout_ms=30 * 60 * 1000
-            )
+            )  # type: ResponseCache[str]
 
         # We reserve `instance_name` as a parameter to sending requests, so we
         # assert here that sub classes don't try and use the name.
diff --git a/synapse/replication/http/federation.py b/synapse/replication/http/federation.py
index 5393b9a9e7..7a0dbb5b1a 100644
--- a/synapse/replication/http/federation.py
+++ b/synapse/replication/http/federation.py
@@ -62,7 +62,7 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
         self.store = hs.get_datastore()
         self.storage = hs.get_storage()
         self.clock = hs.get_clock()
-        self.federation_handler = hs.get_handlers().federation_handler
+        self.federation_handler = hs.get_federation_handler()
 
     @staticmethod
     async def _serialize_payload(store, room_id, event_and_contexts, backfilled):
@@ -254,20 +254,20 @@ class ReplicationCleanRoomRestServlet(ReplicationEndpoint):
         return 200, {}
 
 
-class ReplicationStoreRoomOnInviteRestServlet(ReplicationEndpoint):
+class ReplicationStoreRoomOnOutlierMembershipRestServlet(ReplicationEndpoint):
     """Called to clean up any data in DB for a given room, ready for the
     server to join the room.
 
     Request format:
 
-        POST /_synapse/replication/store_room_on_invite/:room_id/:txn_id
+        POST /_synapse/replication/store_room_on_outlier_membership/:room_id/:txn_id
 
         {
             "room_version": "1",
         }
     """
 
-    NAME = "store_room_on_invite"
+    NAME = "store_room_on_outlier_membership"
     PATH_ARGS = ("room_id",)
 
     def __init__(self, hs):
@@ -282,7 +282,7 @@ class ReplicationStoreRoomOnInviteRestServlet(ReplicationEndpoint):
     async def _handle_request(self, request, room_id):
         content = parse_json_object_from_request(request)
         room_version = KNOWN_ROOM_VERSIONS[content["room_version"]]
-        await self.store.maybe_store_room_on_invite(room_id, room_version)
+        await self.store.maybe_store_room_on_outlier_membership(room_id, room_version)
         return 200, {}
 
 
@@ -291,4 +291,4 @@ def register_servlets(hs, http_server):
     ReplicationFederationSendEduRestServlet(hs).register(http_server)
     ReplicationGetQueryRestServlet(hs).register(http_server)
     ReplicationCleanRoomRestServlet(hs).register(http_server)
-    ReplicationStoreRoomOnInviteRestServlet(hs).register(http_server)
+    ReplicationStoreRoomOnOutlierMembershipRestServlet(hs).register(http_server)
diff --git a/synapse/replication/http/membership.py b/synapse/replication/http/membership.py
index 30680baee8..84e002f934 100644
--- a/synapse/replication/http/membership.py
+++ b/synapse/replication/http/membership.py
@@ -12,9 +12,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import logging
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING, List, Optional, Tuple
+
+from twisted.web.http import Request
 
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.replication.http._base import ReplicationEndpoint
@@ -47,21 +48,28 @@ class ReplicationRemoteJoinRestServlet(ReplicationEndpoint):
     def __init__(self, hs):
         super().__init__(hs)
 
-        self.federation_handler = hs.get_handlers().federation_handler
+        self.federation_handler = hs.get_federation_handler()
         self.store = hs.get_datastore()
         self.clock = hs.get_clock()
 
     @staticmethod
-    async def _serialize_payload(
-        requester, room_id, user_id, remote_room_hosts, content
-    ):
+    async def _serialize_payload(  # type: ignore
+        requester: Requester,
+        room_id: str,
+        user_id: str,
+        remote_room_hosts: List[str],
+        content: JsonDict,
+    ) -> JsonDict:
         """
         Args:
-            requester(Requester)
-            room_id (str)
-            user_id (str)
-            remote_room_hosts (list[str]): Servers to try and join via
-            content(dict): The event content to use for the join event
+            requester: The user making the request according to the access token
+            room_id: The ID of the room.
+            user_id: The ID of the user.
+            remote_room_hosts: Servers to try and join via
+            content: The event content to use for the join event
+
+        Returns:
+            A dict representing the payload of the request.
         """
         return {
             "requester": requester.serialize(),
@@ -69,7 +77,9 @@ class ReplicationRemoteJoinRestServlet(ReplicationEndpoint):
             "content": content,
         }
 
-    async def _handle_request(self, request, room_id, user_id):
+    async def _handle_request(  # type: ignore
+        self, request: Request, room_id: str, user_id: str
+    ) -> Tuple[int, JsonDict]:
         content = parse_json_object_from_request(request)
 
         remote_room_hosts = content["remote_room_hosts"]
@@ -77,8 +87,7 @@ class ReplicationRemoteJoinRestServlet(ReplicationEndpoint):
 
         requester = Requester.deserialize(self.store, content["requester"])
 
-        if requester.user:
-            request.authenticated_entity = requester.user.to_string()
+        request.requester = requester
 
         logger.info("remote_join: %s into room: %s", user_id, room_id)
 
@@ -119,14 +128,17 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
         txn_id: Optional[str],
         requester: Requester,
         content: JsonDict,
-    ):
+    ) -> JsonDict:
         """
         Args:
-            invite_event_id: ID of the invite to be rejected
-            txn_id: optional transaction ID supplied by the client
-            requester: user making the rejection request, according to the access token
-            content: additional content to include in the rejection event.
+            invite_event_id: The ID of the invite to be rejected.
+            txn_id: Optional transaction ID supplied by the client
+            requester: User making the rejection request, according to the access token
+            content: Additional content to include in the rejection event.
                Normally an empty dict.
+
+        Returns:
+            A dict representing the payload of the request.
         """
         return {
             "txn_id": txn_id,
@@ -134,7 +146,9 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
             "content": content,
         }
 
-    async def _handle_request(self, request, invite_event_id):
+    async def _handle_request(  # type: ignore
+        self, request: Request, invite_event_id: str
+    ) -> Tuple[int, JsonDict]:
         content = parse_json_object_from_request(request)
 
         txn_id = content["txn_id"]
@@ -142,8 +156,7 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
 
         requester = Requester.deserialize(self.store, content["requester"])
 
-        if requester.user:
-            request.authenticated_entity = requester.user.to_string()
+        request.requester = requester
 
         # hopefully we're now on the master, so this won't recurse!
         event_id, stream_id = await self.member_handler.remote_reject_invite(
@@ -176,18 +189,25 @@ class ReplicationUserJoinedLeftRoomRestServlet(ReplicationEndpoint):
         self.distributor = hs.get_distributor()
 
     @staticmethod
-    async def _serialize_payload(room_id, user_id, change):
+    async def _serialize_payload(  # type: ignore
+        room_id: str, user_id: str, change: str
+    ) -> JsonDict:
         """
         Args:
-            room_id (str)
-            user_id (str)
-            change (str): "left"
+            room_id: The ID of the room.
+            user_id: The ID of the user.
+            change: "left"
+
+        Returns:
+            A dict representing the payload of the request.
         """
         assert change == "left"
 
         return {}
 
-    def _handle_request(self, request, room_id, user_id, change):
+    def _handle_request(  # type: ignore
+        self, request: Request, room_id: str, user_id: str, change: str
+    ) -> Tuple[int, JsonDict]:
         logger.info("user membership change: %s in %s", user_id, room_id)
 
         user = UserID.from_string(user_id)
diff --git a/synapse/replication/http/send_event.py b/synapse/replication/http/send_event.py
index 9a3a694d5d..8fa104c8d3 100644
--- a/synapse/replication/http/send_event.py
+++ b/synapse/replication/http/send_event.py
@@ -46,6 +46,12 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
             "ratelimit": true,
             "extra_users": [],
         }
+
+        200 OK
+
+        { "stream_id": 12345, "event_id": "$abcdef..." }
+
+    The returned event ID may not match the sent event if it was deduplicated.
     """
 
     NAME = "send_event"
@@ -109,18 +115,23 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
             ratelimit = content["ratelimit"]
             extra_users = [UserID.from_string(u) for u in content["extra_users"]]
 
-        if requester.user:
-            request.authenticated_entity = requester.user.to_string()
+        request.requester = requester
 
         logger.info(
             "Got event to send with ID: %s into room: %s", event.event_id, event.room_id
         )
 
-        stream_id = await self.event_creation_handler.persist_and_notify_client_event(
+        event = await self.event_creation_handler.persist_and_notify_client_event(
             requester, event, context, ratelimit=ratelimit, extra_users=extra_users
         )
 
-        return 200, {"stream_id": stream_id}
+        return (
+            200,
+            {
+                "stream_id": event.internal_metadata.stream_ordering,
+                "event_id": event.event_id,
+            },
+        )
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/replication/slave/storage/client_ips.py b/synapse/replication/slave/storage/client_ips.py
index 1f8dafe7ea..0f5b7adef7 100644
--- a/synapse/replication/slave/storage/client_ips.py
+++ b/synapse/replication/slave/storage/client_ips.py
@@ -15,7 +15,7 @@
 
 from synapse.storage.database import DatabasePool
 from synapse.storage.databases.main.client_ips import LAST_SEEN_GRANULARITY
-from synapse.util.caches.descriptors import Cache
+from synapse.util.caches.lrucache import LruCache
 
 from ._base import BaseSlavedStore
 
@@ -24,9 +24,9 @@ class SlavedClientIpStore(BaseSlavedStore):
     def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
 
-        self.client_ip_last_seen = Cache(
-            name="client_ip_last_seen", keylen=4, max_entries=50000
-        )
+        self.client_ip_last_seen = LruCache(
+            cache_name="client_ip_last_seen", keylen=4, max_size=50000
+        )  # type: LruCache[tuple, int]
 
     async def insert_client_ip(self, user_id, access_token, ip, user_agent, device_id):
         now = int(self._clock.time_msec())
@@ -41,7 +41,7 @@ class SlavedClientIpStore(BaseSlavedStore):
         if last_seen is not None and (now - last_seen) < LAST_SEEN_GRANULARITY:
             return
 
-        self.client_ip_last_seen.prefill(key, now)
+        self.client_ip_last_seen.set(key, now)
 
         self.hs.get_tcp_replication().send_user_ip(
             user_id, access_token, ip, user_agent, device_id, now
diff --git a/synapse/replication/tcp/client.py b/synapse/replication/tcp/client.py
index e165429cad..2618eb1e53 100644
--- a/synapse/replication/tcp/client.py
+++ b/synapse/replication/tcp/client.py
@@ -141,21 +141,25 @@ class ReplicationDataHandler:
                 if row.type != EventsStreamEventRow.TypeId:
                     continue
                 assert isinstance(row, EventsStreamRow)
+                assert isinstance(row.data, EventsStreamEventRow)
 
-                event = await self.store.get_event(
-                    row.data.event_id, allow_rejected=True
-                )
-                if event.rejected_reason:
+                if row.data.rejected:
                     continue
 
                 extra_users = ()  # type: Tuple[UserID, ...]
-                if event.type == EventTypes.Member:
-                    extra_users = (UserID.from_string(event.state_key),)
+                if row.data.type == EventTypes.Member and row.data.state_key:
+                    extra_users = (UserID.from_string(row.data.state_key),)
 
                 max_token = self.store.get_room_max_token()
                 event_pos = PersistedEventPosition(instance_name, token)
-                self.notifier.on_new_room_event(
-                    event, event_pos, max_token, extra_users
+                self.notifier.on_new_room_event_args(
+                    event_pos=event_pos,
+                    max_room_stream_token=max_token,
+                    extra_users=extra_users,
+                    room_id=row.data.room_id,
+                    event_type=row.data.type,
+                    state_key=row.data.state_key,
+                    membership=row.data.membership,
                 )
 
         # Notify any waiting deferreds. The list is ordered by position so we
@@ -191,6 +195,10 @@ class ReplicationDataHandler:
     async def on_position(self, stream_name: str, instance_name: str, token: int):
         self.store.process_replication_rows(stream_name, instance_name, token, [])
 
+        # We poke the generic "replication" notifier to wake anything up that
+        # may be streaming.
+        self.notifier.notify_replication()
+
     def on_remote_server_up(self, server: str):
         """Called when get a new REMOTE_SERVER_UP command."""
 
diff --git a/synapse/replication/tcp/commands.py b/synapse/replication/tcp/commands.py
index 8cd47770c1..ac532ed588 100644
--- a/synapse/replication/tcp/commands.py
+++ b/synapse/replication/tcp/commands.py
@@ -141,15 +141,23 @@ class RdataCommand(Command):
 
 
 class PositionCommand(Command):
-    """Sent by the server to tell the client the stream position without
-    needing to send an RDATA.
+    """Sent by an instance to tell others the stream position without needing to
+    send an RDATA.
+
+    Two tokens are sent, the new position and the last position sent by the
+    instance (in an RDATA or other POSITION). The tokens are chosen so that *no*
+    rows were written by the instance between the `prev_token` and `new_token`.
+    (If an instance hasn't sent a position before then the new position can be
+    used for both.)
 
     Format::
 
-        POSITION <stream_name> <instance_name> <token>
+        POSITION <stream_name> <instance_name> <prev_token> <new_token>
 
-    On receipt of a POSITION command clients should check if they have missed
-    any updates, and if so then fetch them out of band.
+    On receipt of a POSITION command instances should check if they have missed
+    any updates, and if so then fetch them out of band. Instances can check this
+    by comparing their view of the current token for the sending instance with
+    the included `prev_token`.
 
     The `<instance_name>` is the process that sent the command and is the source
     of the stream.
@@ -157,18 +165,26 @@ class PositionCommand(Command):
 
     NAME = "POSITION"
 
-    def __init__(self, stream_name, instance_name, token):
+    def __init__(self, stream_name, instance_name, prev_token, new_token):
         self.stream_name = stream_name
         self.instance_name = instance_name
-        self.token = token
+        self.prev_token = prev_token
+        self.new_token = new_token
 
     @classmethod
     def from_line(cls, line):
-        stream_name, instance_name, token = line.split(" ", 2)
-        return cls(stream_name, instance_name, int(token))
+        stream_name, instance_name, prev_token, new_token = line.split(" ", 3)
+        return cls(stream_name, instance_name, int(prev_token), int(new_token))
 
     def to_line(self):
-        return " ".join((self.stream_name, self.instance_name, str(self.token)))
+        return " ".join(
+            (
+                self.stream_name,
+                self.instance_name,
+                str(self.prev_token),
+                str(self.new_token),
+            )
+        )
 
 
 class ErrorCommand(_SimpleCommand):
diff --git a/synapse/replication/tcp/handler.py b/synapse/replication/tcp/handler.py
index b323841f73..95e5502bf2 100644
--- a/synapse/replication/tcp/handler.py
+++ b/synapse/replication/tcp/handler.py
@@ -101,8 +101,9 @@ class ReplicationCommandHandler:
         self._streams_to_replicate = []  # type: List[Stream]
 
         for stream in self._streams.values():
-            if stream.NAME == CachesStream.NAME:
-                # All workers can write to the cache invalidation stream.
+            if hs.config.redis.redis_enabled and stream.NAME == CachesStream.NAME:
+                # All workers can write to the cache invalidation stream when
+                # using redis.
                 self._streams_to_replicate.append(stream)
                 continue
 
@@ -251,10 +252,9 @@ class ReplicationCommandHandler:
         using TCP.
         """
         if hs.config.redis.redis_enabled:
-            import txredisapi
-
             from synapse.replication.tcp.redis import (
                 RedisDirectTcpReplicationClientFactory,
+                lazyConnection,
             )
 
             logger.info(
@@ -271,7 +271,8 @@ class ReplicationCommandHandler:
             # connection after SUBSCRIBE is called).
 
             # First create the connection for sending commands.
-            outbound_redis_connection = txredisapi.lazyConnection(
+            outbound_redis_connection = lazyConnection(
+                reactor=hs.get_reactor(),
                 host=hs.config.redis_host,
                 port=hs.config.redis_port,
                 password=hs.config.redis.redis_password,
@@ -313,11 +314,14 @@ class ReplicationCommandHandler:
         # We respond with current position of all streams this instance
         # replicates.
         for stream in self.get_streams_to_replicate():
+            # Note that we use the current token as the prev token here (rather
+            # than stream.last_token), as we can't be sure that there have been
+            # no rows written between last token and the current token (since we
+            # might be racing with the replication sending bg process).
+            current_token = stream.current_token(self._instance_name)
             self.send_command(
                 PositionCommand(
-                    stream.NAME,
-                    self._instance_name,
-                    stream.current_token(self._instance_name),
+                    stream.NAME, self._instance_name, current_token, current_token,
                 )
             )
 
@@ -511,16 +515,16 @@ class ReplicationCommandHandler:
         # If the position token matches our current token then we're up to
         # date and there's nothing to do. Otherwise, fetch all updates
         # between then and now.
-        missing_updates = cmd.token != current_token
+        missing_updates = cmd.prev_token != current_token
         while missing_updates:
             logger.info(
                 "Fetching replication rows for '%s' between %i and %i",
                 stream_name,
                 current_token,
-                cmd.token,
+                cmd.new_token,
             )
             (updates, current_token, missing_updates) = await stream.get_updates_since(
-                cmd.instance_name, current_token, cmd.token
+                cmd.instance_name, current_token, cmd.new_token
             )
 
             # TODO: add some tests for this
@@ -536,11 +540,11 @@ class ReplicationCommandHandler:
                     [stream.parse_row(row) for row in rows],
                 )
 
-        logger.info("Caught up with stream '%s' to %i", stream_name, cmd.token)
+        logger.info("Caught up with stream '%s' to %i", stream_name, cmd.new_token)
 
         # We've now caught up to position sent to us, notify handler.
         await self._replication_data_handler.on_position(
-            cmd.stream_name, cmd.instance_name, cmd.token
+            cmd.stream_name, cmd.instance_name, cmd.new_token
         )
 
         self._streams_by_connection.setdefault(conn, set()).add(stream_name)
diff --git a/synapse/replication/tcp/protocol.py b/synapse/replication/tcp/protocol.py
index 0b0d204e64..a509e599c2 100644
--- a/synapse/replication/tcp/protocol.py
+++ b/synapse/replication/tcp/protocol.py
@@ -51,10 +51,11 @@ import fcntl
 import logging
 import struct
 from inspect import isawaitable
-from typing import TYPE_CHECKING, List
+from typing import TYPE_CHECKING, List, Optional
 
 from prometheus_client import Counter
 
+from twisted.internet import task
 from twisted.protocols.basic import LineOnlyReceiver
 from twisted.python.failure import Failure
 
@@ -152,9 +153,10 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
 
         self.last_received_command = self.clock.time_msec()
         self.last_sent_command = 0
-        self.time_we_closed = None  # When we requested the connection be closed
+        # When we requested the connection be closed
+        self.time_we_closed = None  # type: Optional[int]
 
-        self.received_ping = False  # Have we reecived a ping from the other side
+        self.received_ping = False  # Have we received a ping from the other side
 
         self.state = ConnectionStates.CONNECTING
 
@@ -165,7 +167,7 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
         self.pending_commands = []  # type: List[Command]
 
         # The LoopingCall for sending pings.
-        self._send_ping_loop = None
+        self._send_ping_loop = None  # type: Optional[task.LoopingCall]
 
         # a logcontext which we use for processing incoming commands. We declare it as a
         # background process so that the CPU stats get reported to prometheus.
diff --git a/synapse/replication/tcp/redis.py b/synapse/replication/tcp/redis.py
index f225e533de..bc6ba709a7 100644
--- a/synapse/replication/tcp/redis.py
+++ b/synapse/replication/tcp/redis.py
@@ -15,7 +15,7 @@
 
 import logging
 from inspect import isawaitable
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 
 import txredisapi
 
@@ -166,7 +166,9 @@ class RedisSubscriber(txredisapi.SubscriberProtocol, AbstractConnection):
         Args:
             cmd (Command)
         """
-        run_as_background_process("send-cmd", self._async_send_command, cmd)
+        run_as_background_process(
+            "send-cmd", self._async_send_command, cmd, bg_start_span=False
+        )
 
     async def _async_send_command(self, cmd: Command):
         """Encode a replication command and send it over our outbound connection"""
@@ -228,3 +230,41 @@ class RedisDirectTcpReplicationClientFactory(txredisapi.SubscriberFactory):
         p.password = self.password
 
         return p
+
+
+def lazyConnection(
+    reactor,
+    host: str = "localhost",
+    port: int = 6379,
+    dbid: Optional[int] = None,
+    reconnect: bool = True,
+    charset: str = "utf-8",
+    password: Optional[str] = None,
+    connectTimeout: Optional[int] = None,
+    replyTimeout: Optional[int] = None,
+    convertNumbers: bool = True,
+) -> txredisapi.RedisProtocol:
+    """Equivalent to `txredisapi.lazyConnection`, except allows specifying a
+    reactor.
+    """
+
+    isLazy = True
+    poolsize = 1
+
+    uuid = "%s:%d" % (host, port)
+    factory = txredisapi.RedisFactory(
+        uuid,
+        dbid,
+        poolsize,
+        isLazy,
+        txredisapi.ConnectionHandler,
+        charset,
+        password,
+        replyTimeout,
+        convertNumbers,
+    )
+    factory.continueTrying = reconnect
+    for x in range(poolsize):
+        reactor.connectTCP(host, port, factory, connectTimeout)
+
+    return factory.handler
diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py
index 687984e7a8..1d4ceac0f1 100644
--- a/synapse/replication/tcp/resource.py
+++ b/synapse/replication/tcp/resource.py
@@ -23,7 +23,9 @@ from prometheus_client import Counter
 from twisted.internet.protocol import Factory
 
 from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.replication.tcp.commands import PositionCommand
 from synapse.replication.tcp.protocol import ServerReplicationStreamProtocol
+from synapse.replication.tcp.streams import EventsStream
 from synapse.util.metrics import Measure
 
 stream_updates_counter = Counter(
@@ -84,6 +86,23 @@ class ReplicationStreamer:
         # Set of streams to replicate.
         self.streams = self.command_handler.get_streams_to_replicate()
 
+        # If we have streams then we must have redis enabled or on master
+        assert (
+            not self.streams
+            or hs.config.redis.redis_enabled
+            or not hs.config.worker.worker_app
+        )
+
+        # If we are replicating an event stream we want to periodically check if
+        # we should send updated POSITIONs. We do this as a looping call rather
+        # explicitly poking when the position advances (without new data to
+        # replicate) to reduce replication traffic (otherwise each writer would
+        # likely send a POSITION for each new event received over replication).
+        #
+        # Note that if the position hasn't advanced then we won't send anything.
+        if any(EventsStream.NAME == s.NAME for s in self.streams):
+            self.clock.looping_call(self.on_notifier_poke, 1000)
+
     def on_notifier_poke(self):
         """Checks if there is actually any new data and sends it to the
         connections if there are.
@@ -91,13 +110,23 @@ class ReplicationStreamer:
         This should get called each time new data is available, even if it
         is currently being executed, so that nothing gets missed
         """
-        if not self.command_handler.connected():
+        if not self.command_handler.connected() or not self.streams:
             # Don't bother if nothing is listening. We still need to advance
             # the stream tokens otherwise they'll fall behind forever
             for stream in self.streams:
                 stream.discard_updates_and_advance()
             return
 
+        # We check up front to see if anything has actually changed, as we get
+        # poked because of changes that happened on other instances.
+        if all(
+            stream.last_token == stream.current_token(self._instance_name)
+            for stream in self.streams
+        ):
+            return
+
+        # If there are updates then we need to set this even if we're already
+        # looping, as the loop needs to know that he might need to loop again.
         self.pending_updates = True
 
         if self.is_looping:
@@ -136,6 +165,8 @@ class ReplicationStreamer:
                                 self._replication_torture_level / 1000.0
                             )
 
+                        last_token = stream.last_token
+
                         logger.debug(
                             "Getting stream: %s: %s -> %s",
                             stream.NAME,
@@ -159,6 +190,30 @@ class ReplicationStreamer:
                             )
                             stream_updates_counter.labels(stream.NAME).inc(len(updates))
 
+                        else:
+                            # The token has advanced but there is no data to
+                            # send, so we send a `POSITION` to inform other
+                            # workers of the updated position.
+                            if stream.NAME == EventsStream.NAME:
+                                # XXX: We only do this for the EventStream as it
+                                # turns out that e.g. account data streams share
+                                # their "current token" with each other, meaning
+                                # that it is *not* safe to send a POSITION.
+                                logger.info(
+                                    "Sending position: %s -> %s",
+                                    stream.NAME,
+                                    current_token,
+                                )
+                                self.command_handler.send_command(
+                                    PositionCommand(
+                                        stream.NAME,
+                                        self._instance_name,
+                                        last_token,
+                                        current_token,
+                                    )
+                                )
+                            continue
+
                         # Some streams return multiple rows with the same stream IDs,
                         # we need to make sure they get sent out in batches. We do
                         # this by setting the current token to all but the last of
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index 54dccd15a6..61b282ab2d 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -240,13 +240,18 @@ class BackfillStream(Stream):
     ROW_TYPE = BackfillStreamRow
 
     def __init__(self, hs):
-        store = hs.get_datastore()
+        self.store = hs.get_datastore()
         super().__init__(
             hs.get_instance_name(),
-            current_token_without_instance(store.get_current_backfill_token),
-            store.get_all_new_backfill_event_rows,
+            self._current_token,
+            self.store.get_all_new_backfill_event_rows,
         )
 
+    def _current_token(self, instance_name: str) -> int:
+        # The backfill stream over replication operates on *positive* numbers,
+        # which means we need to negate it.
+        return -self.store._backfill_id_gen.get_current_token_for_writer(instance_name)
+
 
 class PresenceStream(Stream):
     PresenceStreamRow = namedtuple(
diff --git a/synapse/replication/tcp/streams/events.py b/synapse/replication/tcp/streams/events.py
index ccc7ca30d8..86a62b71eb 100644
--- a/synapse/replication/tcp/streams/events.py
+++ b/synapse/replication/tcp/streams/events.py
@@ -15,12 +15,15 @@
 # limitations under the License.
 import heapq
 from collections.abc import Iterable
-from typing import List, Tuple, Type
+from typing import TYPE_CHECKING, List, Optional, Tuple, Type
 
 import attr
 
 from ._base import Stream, StreamUpdateResult, Token
 
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
 """Handling of the 'events' replication stream
 
 This stream contains rows of various types. Each row therefore contains a 'type'
@@ -81,12 +84,14 @@ class BaseEventsStreamRow:
 class EventsStreamEventRow(BaseEventsStreamRow):
     TypeId = "ev"
 
-    event_id = attr.ib()  # str
-    room_id = attr.ib()  # str
-    type = attr.ib()  # str
-    state_key = attr.ib()  # str, optional
-    redacts = attr.ib()  # str, optional
-    relates_to = attr.ib()  # str, optional
+    event_id = attr.ib(type=str)
+    room_id = attr.ib(type=str)
+    type = attr.ib(type=str)
+    state_key = attr.ib(type=Optional[str])
+    redacts = attr.ib(type=Optional[str])
+    relates_to = attr.ib(type=Optional[str])
+    membership = attr.ib(type=Optional[str])
+    rejected = attr.ib(type=bool)
 
 
 @attr.s(slots=True, frozen=True)
@@ -113,7 +118,7 @@ class EventsStream(Stream):
 
     NAME = "events"
 
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         self._store = hs.get_datastore()
         super().__init__(
             hs.get_instance_name(),
@@ -155,7 +160,7 @@ class EventsStream(Stream):
         # now we fetch up to that many rows from the events table
 
         event_rows = await self._store.get_all_new_forward_event_rows(
-            from_token, current_token, target_row_count
+            instance_name, from_token, current_token, target_row_count
         )  # type: List[Tuple]
 
         # we rely on get_all_new_forward_event_rows strictly honouring the limit, so
@@ -180,7 +185,7 @@ class EventsStream(Stream):
             upper_limit,
             state_rows_limited,
         ) = await self._store.get_all_updated_current_state_deltas(
-            from_token, upper_limit, target_row_count
+            instance_name, from_token, upper_limit, target_row_count
         )
 
         limited = limited or state_rows_limited
@@ -189,7 +194,7 @@ class EventsStream(Stream):
         # not to bother with the limit.
 
         ex_outliers_rows = await self._store.get_ex_outlier_stream_rows(
-            from_token, upper_limit
+            instance_name, from_token, upper_limit
         )  # type: List[Tuple]
 
         # we now need to turn the raw database rows returned into tuples suitable
diff --git a/synapse/res/templates/notif.html b/synapse/res/templates/notif.html
index 1a6c70b562..6d76064d13 100644
--- a/synapse/res/templates/notif.html
+++ b/synapse/res/templates/notif.html
@@ -1,41 +1,47 @@
-{% for message in notif.messages %}
+{%- for message in notif.messages %}
     <tr class="{{ "historical_message" if message.is_historical else "message" }}">
         <td class="sender_avatar">
-            {% if loop.index0 == 0 or notif.messages[loop.index0 - 1].sender_name != notif.messages[loop.index0].sender_name %}
-                {% if message.sender_avatar_url %}
+            {%- if loop.index0 == 0 or notif.messages[loop.index0 - 1].sender_name != notif.messages[loop.index0].sender_name %}
+                {%- if message.sender_avatar_url %}
                     <img alt="" class="sender_avatar" src="{{ message.sender_avatar_url|mxc_to_http(32,32) }}"  />
-                {% else %}
-                    {% if message.sender_hash % 3 == 0 %}
+                {%- else %}
+                    {%- if message.sender_hash % 3 == 0 %}
                         <img class="sender_avatar" src="https://riot.im/img/external/avatar-1.png"  />
-                    {% elif message.sender_hash % 3 == 1 %}
+                    {%- elif message.sender_hash % 3 == 1 %}
                         <img class="sender_avatar" src="https://riot.im/img/external/avatar-2.png"  />
-                    {% else %}
+                    {%- else %}
                         <img class="sender_avatar" src="https://riot.im/img/external/avatar-3.png"  />
-                    {% endif %}
-                {% endif %}
-            {% endif %}
+                    {%- endif %}
+                {%- endif %}
+            {%- endif %}
         </td>
         <td class="message_contents">
-            {% if loop.index0 == 0 or notif.messages[loop.index0 - 1].sender_name != notif.messages[loop.index0].sender_name %}
-                <div class="sender_name">{% if message.msgtype == "m.emote" %}*{% endif %} {{ message.sender_name }}</div>
-            {% endif %}
+            {%- if loop.index0 == 0 or notif.messages[loop.index0 - 1].sender_name != notif.messages[loop.index0].sender_name %}
+                <div class="sender_name">{%- if message.msgtype == "m.emote" %}*{%- endif %} {{ message.sender_name }}</div>
+            {%- endif %}
             <div class="message_body">
-                {% if message.msgtype == "m.text" %}
-                    {{ message.body_text_html }}
-                {% elif message.msgtype == "m.emote" %}
-                    {{ message.body_text_html }}
-                {% elif message.msgtype == "m.notice" %}
-                    {{ message.body_text_html }}
-                {% elif message.msgtype == "m.image" %}
-                    <img src="{{ message.image_url|mxc_to_http(640, 480, scale) }}" />
-                {% elif message.msgtype == "m.file" %}
-                    <span class="filename">{{ message.body_text_plain }}</span>
-                {% endif %}
+                {%- if message.event_type == "m.room.encrypted" %}
+                    An encrypted message.
+                {%- elif message.event_type == "m.room.message" %}
+                    {%- if message.msgtype == "m.text" %}
+                        {{ message.body_text_html }}
+                    {%- elif message.msgtype == "m.emote" %}
+                        {{ message.body_text_html }}
+                    {%- elif message.msgtype == "m.notice" %}
+                        {{ message.body_text_html }}
+                    {%- elif message.msgtype == "m.image" %}
+                        <img src="{{ message.image_url|mxc_to_http(640, 480, scale) }}" />
+                    {%- elif message.msgtype == "m.file" %}
+                        <span class="filename">{{ message.body_text_plain }}</span>
+                    {%- else %}
+                        A message with unrecognised content.
+                    {%- endif %}
+                {%- endif %}
             </div>
         </td>
         <td class="message_time">{{ message.ts|format_ts("%H:%M") }}</td>
     </tr>
-{% endfor %}
+{%- endfor %}
 <tr class="notif_link">
     <td></td>
     <td>
diff --git a/synapse/res/templates/notif.txt b/synapse/res/templates/notif.txt
index a37bee9833..1ee7da3c50 100644
--- a/synapse/res/templates/notif.txt
+++ b/synapse/res/templates/notif.txt
@@ -1,16 +1,22 @@
-{% for message in notif.messages %}
-{% if message.msgtype == "m.emote" %}* {% endif %}{{ message.sender_name }} ({{ message.ts|format_ts("%H:%M") }})
-{% if message.msgtype == "m.text" %}
+{%- for message in notif.messages %}
+{%- if message.event_type == "m.room.encrypted" %}
+An encrypted message.
+{%- elif message.event_type == "m.room.message" %}
+{%- if message.msgtype == "m.emote" %}* {%- endif %}{{ message.sender_name }} ({{ message.ts|format_ts("%H:%M") }})
+{%- if message.msgtype == "m.text" %}
 {{ message.body_text_plain }}
-{% elif message.msgtype == "m.emote" %}
+{%- elif message.msgtype == "m.emote" %}
 {{ message.body_text_plain }}
-{% elif message.msgtype == "m.notice" %}
+{%- elif message.msgtype == "m.notice" %}
 {{ message.body_text_plain }}
-{% elif message.msgtype == "m.image" %}
+{%- elif message.msgtype == "m.image" %}
 {{ message.body_text_plain }}
-{% elif message.msgtype == "m.file" %}
+{%- elif message.msgtype == "m.file" %}
 {{ message.body_text_plain }}
-{% endif %}
-{% endfor %}
+{%- else %}
+A message with unrecognised content.
+{%- endif %}
+{%- endif %}
+{%- endfor %}
 
 View {{ room.title }} at {{ notif.link }}
diff --git a/synapse/res/templates/notif_mail.html b/synapse/res/templates/notif_mail.html
index a2dfeb9e9f..27d4182790 100644
--- a/synapse/res/templates/notif_mail.html
+++ b/synapse/res/templates/notif_mail.html
@@ -2,8 +2,8 @@
 <html lang="en">
     <head>
         <style type="text/css">
-            {% include 'mail.css' without context %}
-            {% include "mail-%s.css" % app_name ignore missing without context %}
+            {%- include 'mail.css' without context %}
+            {%- include "mail-%s.css" % app_name ignore missing without context %}
         </style>
     </head>
     <body>
@@ -18,21 +18,21 @@
                                 <div class="summarytext">{{ summary_text }}</div>
                             </td>
                             <td class="logo">
-                                {% if app_name == "Riot" %}
+                                {%- if app_name == "Riot" %}
                                     <img src="http://riot.im/img/external/riot-logo-email.png" width="83" height="83" alt="[Riot]"/>
-                                {% elif app_name == "Vector" %}
+                                {%- elif app_name == "Vector" %}
                                     <img src="http://matrix.org/img/vector-logo-email.png" width="64" height="83" alt="[Vector]"/>
-                                {% elif app_name == "Element" %}
+                                {%- elif app_name == "Element" %}
                                     <img src="https://static.element.io/images/email-logo.png" width="83" height="83" alt="[Element]"/>
-                                {% else %}
+                                {%- else %}
                                     <img src="http://matrix.org/img/matrix-120x51.png" width="120" height="51" alt="[matrix]"/>
-                                {% endif %}
+                                {%- endif %}
                             </td>
                         </tr>
                     </table>
-                    {% for room in rooms %}
-                        {% include 'room.html' with context %}
-                    {% endfor %}
+                    {%- for room in rooms %}
+                        {%- include 'room.html' with context %}
+                    {%- endfor %}
                     <div class="footer">
                         <a href="{{ unsubscribe_link }}">Unsubscribe</a>
                         <br/>
@@ -41,12 +41,12 @@
                             Sending email at {{ reason.now|format_ts("%c") }} due to activity in room {{ reason.room_name }} because
                             an event was received at {{ reason.received_at|format_ts("%c") }}
                             which is more than {{ "%.1f"|format(reason.delay_before_mail_ms / (60*1000)) }} ({{ reason.delay_before_mail_ms }}) mins ago,
-                            {% if reason.last_sent_ts %}
+                            {%- if reason.last_sent_ts %}
                                 and the last time we sent a mail for this room was {{ reason.last_sent_ts|format_ts("%c") }},
                                 which is more than {{ "%.1f"|format(reason.throttle_ms / (60*1000)) }} (current throttle_ms) mins ago.
-                            {% else %}
+                            {%- else %}
                                 and we don't have a last time we sent a mail for this room.
-                            {% endif %}
+                            {%- endif %}
                         </div>
                     </div>
                 </td>
diff --git a/synapse/res/templates/notif_mail.txt b/synapse/res/templates/notif_mail.txt
index 24843042a5..df3c253979 100644
--- a/synapse/res/templates/notif_mail.txt
+++ b/synapse/res/templates/notif_mail.txt
@@ -2,9 +2,9 @@ Hi {{ user_display_name }},
 
 {{ summary_text }}
 
-{% for room in rooms %}
-{% include 'room.txt' with context %}
-{% endfor %}
+{%- for room in rooms %}
+{%- include 'room.txt' with context %}
+{%- endfor %}
 
 You can disable these notifications at {{ unsubscribe_link }}
 
diff --git a/synapse/res/templates/room.html b/synapse/res/templates/room.html
index b8525fef88..4fc6f6ac9b 100644
--- a/synapse/res/templates/room.html
+++ b/synapse/res/templates/room.html
@@ -1,23 +1,23 @@
 <table class="room">
     <tr class="room_header">
         <td class="room_avatar">
-            {% if room.avatar_url %}
+            {%- if room.avatar_url %}
                 <img alt="" src="{{ room.avatar_url|mxc_to_http(48,48) }}" />
-            {% else %}
-                {% if room.hash % 3 == 0 %}
+            {%- else %}
+                {%- if room.hash % 3 == 0 %}
                     <img alt="" src="https://riot.im/img/external/avatar-1.png"  />
-                {% elif room.hash % 3 == 1 %}
+                {%- elif room.hash % 3 == 1 %}
                     <img alt="" src="https://riot.im/img/external/avatar-2.png"  />
-                {% else %}
+                {%- else %}
                     <img alt="" src="https://riot.im/img/external/avatar-3.png"  />
-                {% endif %}
-            {% endif %}
+                {%- endif %}
+            {%- endif %}
         </td>
         <td class="room_name" colspan="2">
             {{ room.title }}
         </td>
     </tr>
-    {% if room.invite %}
+    {%- if room.invite %}
         <tr>
             <td></td>
             <td>
@@ -25,9 +25,9 @@
             </td>
             <td></td>
         </tr>
-    {% else %}
-        {% for notif in room.notifs %}
-            {% include 'notif.html' with context %}
-        {% endfor %}
-    {% endif %}
+    {%- else %}
+        {%- for notif in room.notifs %}
+            {%- include 'notif.html' with context %}
+        {%- endfor %}
+    {%- endif %}
 </table>
diff --git a/synapse/res/templates/room.txt b/synapse/res/templates/room.txt
index 84648c710e..df841e9e6f 100644
--- a/synapse/res/templates/room.txt
+++ b/synapse/res/templates/room.txt
@@ -1,9 +1,9 @@
 {{ room.title }}
 
-{% if room.invite %}
+{%- if room.invite %}
     You've been invited, join at {{ room.link }}
-{% else %}
-    {% for notif in room.notifs %}
-        {% include 'notif.txt' with context %}
-    {% endfor %}
-{% endif %}
+{%- else %}
+    {%- for notif in room.notifs %}
+        {%- include 'notif.txt' with context %}
+    {%- endfor %}
+{%- endif %}
diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index 57cac22252..55ddebb4fe 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -21,17 +21,16 @@ import synapse
 from synapse.api.errors import Codes, NotFoundError, SynapseError
 from synapse.http.server import JsonResource
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
-from synapse.rest.admin._base import (
-    admin_patterns,
-    assert_requester_is_admin,
-    historical_admin_path_patterns,
-)
+from synapse.rest.admin._base import admin_patterns, assert_requester_is_admin
 from synapse.rest.admin.devices import (
     DeleteDevicesRestServlet,
     DeviceRestServlet,
     DevicesRestServlet,
 )
-from synapse.rest.admin.event_reports import EventReportsRestServlet
+from synapse.rest.admin.event_reports import (
+    EventReportDetailRestServlet,
+    EventReportsRestServlet,
+)
 from synapse.rest.admin.groups import DeleteGroupAdminRestServlet
 from synapse.rest.admin.media import ListMediaInRoom, register_servlets_for_media_repo
 from synapse.rest.admin.purge_room_servlet import PurgeRoomServlet
@@ -44,19 +43,24 @@ from synapse.rest.admin.rooms import (
     ShutdownRoomRestServlet,
 )
 from synapse.rest.admin.server_notice_servlet import SendServerNoticeServlet
+from synapse.rest.admin.statistics import UserMediaStatisticsRestServlet
 from synapse.rest.admin.users import (
     AccountValidityRenewServlet,
     DeactivateAccountRestServlet,
+    PushersRestServlet,
     ResetPasswordRestServlet,
     SearchUsersRestServlet,
     UserAdminServlet,
+    UserMediaRestServlet,
     UserMembershipRestServlet,
     UserRegisterServlet,
     UserRestServletV2,
     UsersRestServlet,
     UsersRestServletV2,
+    UserTokenRestServlet,
     WhoisRestServlet,
 )
+from synapse.types import RoomStreamToken
 from synapse.util.versionstring import get_version_string
 
 logger = logging.getLogger(__name__)
@@ -76,7 +80,7 @@ class VersionServlet(RestServlet):
 
 
 class PurgeHistoryRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns(
+    PATTERNS = admin_patterns(
         "/purge_history/(?P<room_id>[^/]*)(/(?P<event_id>[^/]+))?"
     )
 
@@ -109,7 +113,9 @@ class PurgeHistoryRestServlet(RestServlet):
             if event.room_id != room_id:
                 raise SynapseError(400, "Event is for wrong room.")
 
-            room_token = await self.store.get_topological_token_for_event(event_id)
+            room_token = RoomStreamToken(
+                event.depth, event.internal_metadata.stream_ordering
+            )
             token = await room_token.to_string(self.store)
 
             logger.info("[purge] purging up to token %s (event_id %s)", token, event_id)
@@ -159,9 +165,7 @@ class PurgeHistoryRestServlet(RestServlet):
 
 
 class PurgeHistoryStatusRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns(
-        "/purge_history_status/(?P<purge_id>[^/]+)"
-    )
+    PATTERNS = admin_patterns("/purge_history_status/(?P<purge_id>[^/]+)")
 
     def __init__(self, hs):
         """
@@ -212,13 +216,18 @@ def register_servlets(hs, http_server):
     SendServerNoticeServlet(hs).register(http_server)
     VersionServlet(hs).register(http_server)
     UserAdminServlet(hs).register(http_server)
+    UserMediaRestServlet(hs).register(http_server)
     UserMembershipRestServlet(hs).register(http_server)
+    UserTokenRestServlet(hs).register(http_server)
     UserRestServletV2(hs).register(http_server)
     UsersRestServletV2(hs).register(http_server)
     DeviceRestServlet(hs).register(http_server)
     DevicesRestServlet(hs).register(http_server)
     DeleteDevicesRestServlet(hs).register(http_server)
+    UserMediaStatisticsRestServlet(hs).register(http_server)
+    EventReportDetailRestServlet(hs).register(http_server)
     EventReportsRestServlet(hs).register(http_server)
+    PushersRestServlet(hs).register(http_server)
 
 
 def register_servlets_for_client_rest_resource(hs, http_server):
diff --git a/synapse/rest/admin/_base.py b/synapse/rest/admin/_base.py
index db9fea263a..e09234c644 100644
--- a/synapse/rest/admin/_base.py
+++ b/synapse/rest/admin/_base.py
@@ -22,28 +22,6 @@ from synapse.api.errors import AuthError
 from synapse.types import UserID
 
 
-def historical_admin_path_patterns(path_regex):
-    """Returns the list of patterns for an admin endpoint, including historical ones
-
-    This is a backwards-compatibility hack. Previously, the Admin API was exposed at
-    various paths under /_matrix/client. This function returns a list of patterns
-    matching those paths (as well as the new one), so that existing scripts which rely
-    on the endpoints being available there are not broken.
-
-    Note that this should only be used for existing endpoints: new ones should just
-    register for the /_synapse/admin path.
-    """
-    return [
-        re.compile(prefix + path_regex)
-        for prefix in (
-            "^/_synapse/admin/v1",
-            "^/_matrix/client/api/v1/admin",
-            "^/_matrix/client/unstable/admin",
-            "^/_matrix/client/r0/admin",
-        )
-    ]
-
-
 def admin_patterns(path_regex: str, version: str = "v1"):
     """Returns the list of patterns for an admin endpoint
 
diff --git a/synapse/rest/admin/devices.py b/synapse/rest/admin/devices.py
index a163863322..ffd3aa38f7 100644
--- a/synapse/rest/admin/devices.py
+++ b/synapse/rest/admin/devices.py
@@ -119,7 +119,7 @@ class DevicesRestServlet(RestServlet):
             raise NotFoundError("Unknown user")
 
         devices = await self.device_handler.get_devices_by_user(target_user.to_string())
-        return 200, {"devices": devices}
+        return 200, {"devices": devices, "total": len(devices)}
 
 
 class DeleteDevicesRestServlet(RestServlet):
diff --git a/synapse/rest/admin/event_reports.py b/synapse/rest/admin/event_reports.py
index 5b8d0594cd..fd482f0e32 100644
--- a/synapse/rest/admin/event_reports.py
+++ b/synapse/rest/admin/event_reports.py
@@ -15,7 +15,7 @@
 
 import logging
 
-from synapse.api.errors import Codes, SynapseError
+from synapse.api.errors import Codes, NotFoundError, SynapseError
 from synapse.http.servlet import RestServlet, parse_integer, parse_string
 from synapse.rest.admin._base import admin_patterns, assert_requester_is_admin
 
@@ -86,3 +86,47 @@ class EventReportsRestServlet(RestServlet):
             ret["next_token"] = start + len(event_reports)
 
         return 200, ret
+
+
+class EventReportDetailRestServlet(RestServlet):
+    """
+    Get a specific reported event that is known to the homeserver. Results are returned
+    in a dictionary containing report information.
+    The requester must have administrator access in Synapse.
+
+    GET /_synapse/admin/v1/event_reports/<report_id>
+    returns:
+        200 OK with details report if success otherwise an error.
+
+    Args:
+        The parameter `report_id` is the ID of the event report in the database.
+    Returns:
+        JSON blob of information about the event report
+    """
+
+    PATTERNS = admin_patterns("/event_reports/(?P<report_id>[^/]*)$")
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.store = hs.get_datastore()
+
+    async def on_GET(self, request, report_id):
+        await assert_requester_is_admin(self.auth, request)
+
+        message = (
+            "The report_id parameter must be a string representing a positive integer."
+        )
+        try:
+            report_id = int(report_id)
+        except ValueError:
+            raise SynapseError(400, message, errcode=Codes.INVALID_PARAM)
+
+        if report_id < 0:
+            raise SynapseError(400, message, errcode=Codes.INVALID_PARAM)
+
+        ret = await self.store.get_event_report(report_id)
+        if not ret:
+            raise NotFoundError("Event report not found")
+
+        return 200, ret
diff --git a/synapse/rest/admin/groups.py b/synapse/rest/admin/groups.py
index 0b54ca09f4..d0c86b204a 100644
--- a/synapse/rest/admin/groups.py
+++ b/synapse/rest/admin/groups.py
@@ -16,10 +16,7 @@ import logging
 
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import RestServlet
-from synapse.rest.admin._base import (
-    assert_user_is_admin,
-    historical_admin_path_patterns,
-)
+from synapse.rest.admin._base import admin_patterns, assert_user_is_admin
 
 logger = logging.getLogger(__name__)
 
@@ -28,7 +25,7 @@ class DeleteGroupAdminRestServlet(RestServlet):
     """Allows deleting of local groups
     """
 
-    PATTERNS = historical_admin_path_patterns("/delete_group/(?P<group_id>[^/]*)")
+    PATTERNS = admin_patterns("/delete_group/(?P<group_id>[^/]*)")
 
     def __init__(self, hs):
         self.group_server = hs.get_groups_server_handler()
diff --git a/synapse/rest/admin/media.py b/synapse/rest/admin/media.py
index ee75095c0e..c82b4f87d6 100644
--- a/synapse/rest/admin/media.py
+++ b/synapse/rest/admin/media.py
@@ -16,12 +16,12 @@
 
 import logging
 
-from synapse.api.errors import AuthError
-from synapse.http.servlet import RestServlet, parse_integer
+from synapse.api.errors import AuthError, Codes, NotFoundError, SynapseError
+from synapse.http.servlet import RestServlet, parse_boolean, parse_integer
 from synapse.rest.admin._base import (
+    admin_patterns,
     assert_requester_is_admin,
     assert_user_is_admin,
-    historical_admin_path_patterns,
 )
 
 logger = logging.getLogger(__name__)
@@ -33,10 +33,10 @@ class QuarantineMediaInRoom(RestServlet):
     """
 
     PATTERNS = (
-        historical_admin_path_patterns("/room/(?P<room_id>[^/]+)/media/quarantine")
+        admin_patterns("/room/(?P<room_id>[^/]+)/media/quarantine")
         +
         # This path kept around for legacy reasons
-        historical_admin_path_patterns("/quarantine_media/(?P<room_id>[^/]+)")
+        admin_patterns("/quarantine_media/(?P<room_id>[^/]+)")
     )
 
     def __init__(self, hs):
@@ -62,9 +62,7 @@ class QuarantineMediaByUser(RestServlet):
     this server.
     """
 
-    PATTERNS = historical_admin_path_patterns(
-        "/user/(?P<user_id>[^/]+)/media/quarantine"
-    )
+    PATTERNS = admin_patterns("/user/(?P<user_id>[^/]+)/media/quarantine")
 
     def __init__(self, hs):
         self.store = hs.get_datastore()
@@ -89,7 +87,7 @@ class QuarantineMediaByID(RestServlet):
     it via this server.
     """
 
-    PATTERNS = historical_admin_path_patterns(
+    PATTERNS = admin_patterns(
         "/media/quarantine/(?P<server_name>[^/]+)/(?P<media_id>[^/]+)"
     )
 
@@ -115,7 +113,7 @@ class ListMediaInRoom(RestServlet):
     """Lists all of the media in a given room.
     """
 
-    PATTERNS = historical_admin_path_patterns("/room/(?P<room_id>[^/]+)/media")
+    PATTERNS = admin_patterns("/room/(?P<room_id>[^/]+)/media")
 
     def __init__(self, hs):
         self.store = hs.get_datastore()
@@ -133,7 +131,7 @@ class ListMediaInRoom(RestServlet):
 
 
 class PurgeMediaCacheRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/purge_media_cache")
+    PATTERNS = admin_patterns("/purge_media_cache")
 
     def __init__(self, hs):
         self.media_repository = hs.get_media_repository()
@@ -150,6 +148,80 @@ class PurgeMediaCacheRestServlet(RestServlet):
         return 200, ret
 
 
+class DeleteMediaByID(RestServlet):
+    """Delete local media by a given ID. Removes it from this server.
+    """
+
+    PATTERNS = admin_patterns("/media/(?P<server_name>[^/]+)/(?P<media_id>[^/]+)")
+
+    def __init__(self, hs):
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.server_name = hs.hostname
+        self.media_repository = hs.get_media_repository()
+
+    async def on_DELETE(self, request, server_name: str, media_id: str):
+        await assert_requester_is_admin(self.auth, request)
+
+        if self.server_name != server_name:
+            raise SynapseError(400, "Can only delete local media")
+
+        if await self.store.get_local_media(media_id) is None:
+            raise NotFoundError("Unknown media")
+
+        logging.info("Deleting local media by ID: %s", media_id)
+
+        deleted_media, total = await self.media_repository.delete_local_media(media_id)
+        return 200, {"deleted_media": deleted_media, "total": total}
+
+
+class DeleteMediaByDateSize(RestServlet):
+    """Delete local media and local copies of remote media by
+    timestamp and size.
+    """
+
+    PATTERNS = admin_patterns("/media/(?P<server_name>[^/]+)/delete")
+
+    def __init__(self, hs):
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.server_name = hs.hostname
+        self.media_repository = hs.get_media_repository()
+
+    async def on_POST(self, request, server_name: str):
+        await assert_requester_is_admin(self.auth, request)
+
+        before_ts = parse_integer(request, "before_ts", required=True)
+        size_gt = parse_integer(request, "size_gt", default=0)
+        keep_profiles = parse_boolean(request, "keep_profiles", default=True)
+
+        if before_ts < 0:
+            raise SynapseError(
+                400,
+                "Query parameter before_ts must be a string representing a positive integer.",
+                errcode=Codes.INVALID_PARAM,
+            )
+        if size_gt < 0:
+            raise SynapseError(
+                400,
+                "Query parameter size_gt must be a string representing a positive integer.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        if self.server_name != server_name:
+            raise SynapseError(400, "Can only delete local media")
+
+        logging.info(
+            "Deleting local media by timestamp: %s, size larger than: %s, keep profile media: %s"
+            % (before_ts, size_gt, keep_profiles)
+        )
+
+        deleted_media, total = await self.media_repository.delete_old_local_media(
+            before_ts, size_gt, keep_profiles
+        )
+        return 200, {"deleted_media": deleted_media, "total": total}
+
+
 def register_servlets_for_media_repo(hs, http_server):
     """
     Media repo specific APIs.
@@ -159,3 +231,5 @@ def register_servlets_for_media_repo(hs, http_server):
     QuarantineMediaByID(hs).register(http_server)
     QuarantineMediaByUser(hs).register(http_server)
     ListMediaInRoom(hs).register(http_server)
+    DeleteMediaByID(hs).register(http_server)
+    DeleteMediaByDateSize(hs).register(http_server)
diff --git a/synapse/rest/admin/rooms.py b/synapse/rest/admin/rooms.py
index 09726d52d6..25f89e4685 100644
--- a/synapse/rest/admin/rooms.py
+++ b/synapse/rest/admin/rooms.py
@@ -29,7 +29,6 @@ from synapse.rest.admin._base import (
     admin_patterns,
     assert_requester_is_admin,
     assert_user_is_admin,
-    historical_admin_path_patterns,
 )
 from synapse.storage.databases.main.room import RoomSortOrder
 from synapse.types import RoomAlias, RoomID, UserID, create_requester
@@ -44,7 +43,7 @@ class ShutdownRoomRestServlet(RestServlet):
     joined to the new room.
     """
 
-    PATTERNS = historical_admin_path_patterns("/shutdown_room/(?P<room_id>[^/]+)")
+    PATTERNS = admin_patterns("/shutdown_room/(?P<room_id>[^/]+)")
 
     def __init__(self, hs):
         self.hs = hs
@@ -71,14 +70,18 @@ class ShutdownRoomRestServlet(RestServlet):
 
 
 class DeleteRoomRestServlet(RestServlet):
-    """Delete a room from server. It is a combination and improvement of
-    shut down and purge room.
+    """Delete a room from server.
+
+    It is a combination and improvement of shutdown and purge room.
+
     Shuts down a room by removing all local users from the room.
     Blocking all future invites and joins to the room is optional.
+
     If desired any local aliases will be repointed to a new room
-    created by `new_room_user_id` and kicked users will be auto
+    created by `new_room_user_id` and kicked users will be auto-
     joined to the new room.
-    It will remove all trace of a room from the database.
+
+    If 'purge' is true, it will remove all traces of a room from the database.
     """
 
     PATTERNS = admin_patterns("/rooms/(?P<room_id>[^/]+)/delete$")
@@ -111,6 +114,14 @@ class DeleteRoomRestServlet(RestServlet):
                 Codes.BAD_JSON,
             )
 
+        force_purge = content.get("force_purge", False)
+        if not isinstance(force_purge, bool):
+            raise SynapseError(
+                HTTPStatus.BAD_REQUEST,
+                "Param 'force_purge' must be a boolean, if given",
+                Codes.BAD_JSON,
+            )
+
         ret = await self.room_shutdown_handler.shutdown_room(
             room_id=room_id,
             new_room_user_id=content.get("new_room_user_id"),
@@ -122,7 +133,7 @@ class DeleteRoomRestServlet(RestServlet):
 
         # Purge room
         if purge:
-            await self.pagination_handler.purge_room(room_id)
+            await self.pagination_handler.purge_room(room_id, force=force_purge)
 
         return (200, ret)
 
@@ -138,7 +149,7 @@ class ListRoomRestServlet(RestServlet):
     def __init__(self, hs):
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
-        self.admin_handler = hs.get_handlers().admin_handler
+        self.admin_handler = hs.get_admin_handler()
 
     async def on_GET(self, request):
         requester = await self.auth.get_user_by_req(request)
@@ -273,7 +284,7 @@ class JoinRoomAliasServlet(RestServlet):
         self.hs = hs
         self.auth = hs.get_auth()
         self.room_member_handler = hs.get_room_member_handler()
-        self.admin_handler = hs.get_handlers().admin_handler
+        self.admin_handler = hs.get_admin_handler()
         self.state_handler = hs.get_state_handler()
 
     async def on_POST(self, request, room_identifier):
@@ -309,7 +320,9 @@ class JoinRoomAliasServlet(RestServlet):
                 400, "%s was not legal room ID or room alias" % (room_identifier,)
             )
 
-        fake_requester = create_requester(target_user)
+        fake_requester = create_requester(
+            target_user, authenticated_entity=requester.authenticated_entity
+        )
 
         # send invite if room has "JoinRules.INVITE"
         room_state = await self.state_handler.get_current_state(room_id)
diff --git a/synapse/rest/admin/statistics.py b/synapse/rest/admin/statistics.py
new file mode 100644
index 0000000000..f2490e382d
--- /dev/null
+++ b/synapse/rest/admin/statistics.py
@@ -0,0 +1,122 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 Dirk Klimpel
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+from typing import TYPE_CHECKING, Tuple
+
+from synapse.api.errors import Codes, SynapseError
+from synapse.http.servlet import RestServlet, parse_integer, parse_string
+from synapse.http.site import SynapseRequest
+from synapse.rest.admin._base import admin_patterns, assert_requester_is_admin
+from synapse.storage.databases.main.stats import UserSortOrder
+from synapse.types import JsonDict
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
+logger = logging.getLogger(__name__)
+
+
+class UserMediaStatisticsRestServlet(RestServlet):
+    """
+    Get statistics about uploaded media by users.
+    """
+
+    PATTERNS = admin_patterns("/statistics/users/media$")
+
+    def __init__(self, hs: "HomeServer"):
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.store = hs.get_datastore()
+
+    async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
+        await assert_requester_is_admin(self.auth, request)
+
+        order_by = parse_string(
+            request, "order_by", default=UserSortOrder.USER_ID.value
+        )
+        if order_by not in (
+            UserSortOrder.MEDIA_LENGTH.value,
+            UserSortOrder.MEDIA_COUNT.value,
+            UserSortOrder.USER_ID.value,
+            UserSortOrder.DISPLAYNAME.value,
+        ):
+            raise SynapseError(
+                400,
+                "Unknown value for order_by: %s" % (order_by,),
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        start = parse_integer(request, "from", default=0)
+        if start < 0:
+            raise SynapseError(
+                400,
+                "Query parameter from must be a string representing a positive integer.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        limit = parse_integer(request, "limit", default=100)
+        if limit < 0:
+            raise SynapseError(
+                400,
+                "Query parameter limit must be a string representing a positive integer.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        from_ts = parse_integer(request, "from_ts", default=0)
+        if from_ts < 0:
+            raise SynapseError(
+                400,
+                "Query parameter from_ts must be a string representing a positive integer.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        until_ts = parse_integer(request, "until_ts")
+        if until_ts is not None:
+            if until_ts < 0:
+                raise SynapseError(
+                    400,
+                    "Query parameter until_ts must be a string representing a positive integer.",
+                    errcode=Codes.INVALID_PARAM,
+                )
+            if until_ts <= from_ts:
+                raise SynapseError(
+                    400,
+                    "Query parameter until_ts must be greater than from_ts.",
+                    errcode=Codes.INVALID_PARAM,
+                )
+
+        search_term = parse_string(request, "search_term")
+        if search_term == "":
+            raise SynapseError(
+                400,
+                "Query parameter search_term cannot be an empty string.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        direction = parse_string(request, "dir", default="f")
+        if direction not in ("f", "b"):
+            raise SynapseError(
+                400, "Unknown direction: %s" % (direction,), errcode=Codes.INVALID_PARAM
+            )
+
+        users_media, total = await self.store.get_users_media_usage_paginate(
+            start, limit, from_ts, until_ts, order_by, direction, search_term
+        )
+        ret = {"users": users_media, "total": total}
+        if (start + limit) < total:
+            ret["next_token"] = start + len(users_media)
+
+        return 200, ret
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index 20dc1d0e05..b0ff5e1ead 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -16,6 +16,7 @@ import hashlib
 import hmac
 import logging
 from http import HTTPStatus
+from typing import TYPE_CHECKING, Tuple
 
 from synapse.api.constants import UserTypes
 from synapse.api.errors import Codes, NotFoundError, SynapseError
@@ -27,25 +28,40 @@ from synapse.http.servlet import (
     parse_json_object_from_request,
     parse_string,
 )
+from synapse.http.site import SynapseRequest
 from synapse.rest.admin._base import (
     admin_patterns,
     assert_requester_is_admin,
     assert_user_is_admin,
-    historical_admin_path_patterns,
 )
-from synapse.types import UserID
+from synapse.rest.client.v2_alpha._base import client_patterns
+from synapse.types import JsonDict, UserID
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
 
 logger = logging.getLogger(__name__)
 
+_GET_PUSHERS_ALLOWED_KEYS = {
+    "app_display_name",
+    "app_id",
+    "data",
+    "device_display_name",
+    "kind",
+    "lang",
+    "profile_tag",
+    "pushkey",
+}
+
 
 class UsersRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/users/(?P<user_id>[^/]*)$")
+    PATTERNS = admin_patterns("/users/(?P<user_id>[^/]*)$")
 
     def __init__(self, hs):
         self.hs = hs
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
-        self.admin_handler = hs.get_handlers().admin_handler
+        self.admin_handler = hs.get_admin_handler()
 
     async def on_GET(self, request, user_id):
         target_user = UserID.from_string(user_id)
@@ -82,7 +98,7 @@ class UsersRestServletV2(RestServlet):
         self.hs = hs
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
-        self.admin_handler = hs.get_handlers().admin_handler
+        self.admin_handler = hs.get_admin_handler()
 
     async def on_GET(self, request):
         await assert_requester_is_admin(self.auth, request)
@@ -135,7 +151,7 @@ class UserRestServletV2(RestServlet):
     def __init__(self, hs):
         self.hs = hs
         self.auth = hs.get_auth()
-        self.admin_handler = hs.get_handlers().admin_handler
+        self.admin_handler = hs.get_admin_handler()
         self.store = hs.get_datastore()
         self.auth_handler = hs.get_auth_handler()
         self.profile_handler = hs.get_profile_handler()
@@ -322,7 +338,7 @@ class UserRegisterServlet(RestServlet):
              nonce to the time it was generated, in int seconds.
     """
 
-    PATTERNS = historical_admin_path_patterns("/register")
+    PATTERNS = admin_patterns("/register")
     NONCE_TIMEOUT = 60
 
     def __init__(self, hs):
@@ -399,6 +415,7 @@ class UserRegisterServlet(RestServlet):
 
         admin = body.get("admin", None)
         user_type = body.get("user_type", None)
+        displayname = body.get("displayname", None)
 
         if user_type is not None and user_type not in UserTypes.ALL_USER_TYPES:
             raise SynapseError(400, "Invalid user type")
@@ -435,6 +452,7 @@ class UserRegisterServlet(RestServlet):
             password_hash=password_hash,
             admin=bool(admin),
             user_type=user_type,
+            default_display_name=displayname,
             by_admin=True,
         )
 
@@ -443,12 +461,19 @@ class UserRegisterServlet(RestServlet):
 
 
 class WhoisRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/whois/(?P<user_id>[^/]*)")
+    path_regex = "/whois/(?P<user_id>[^/]*)$"
+    PATTERNS = (
+        admin_patterns(path_regex)
+        +
+        # URL for spec reason
+        # https://matrix.org/docs/spec/client_server/r0.6.1#get-matrix-client-r0-admin-whois-userid
+        client_patterns("/admin" + path_regex, v1=True)
+    )
 
     def __init__(self, hs):
         self.hs = hs
         self.auth = hs.get_auth()
-        self.handlers = hs.get_handlers()
+        self.admin_handler = hs.get_admin_handler()
 
     async def on_GET(self, request, user_id):
         target_user = UserID.from_string(user_id)
@@ -461,13 +486,13 @@ class WhoisRestServlet(RestServlet):
         if not self.hs.is_mine(target_user):
             raise SynapseError(400, "Can only whois a local user")
 
-        ret = await self.handlers.admin_handler.get_whois(target_user)
+        ret = await self.admin_handler.get_whois(target_user)
 
         return 200, ret
 
 
 class DeactivateAccountRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/deactivate/(?P<target_user_id>[^/]*)")
+    PATTERNS = admin_patterns("/deactivate/(?P<target_user_id>[^/]*)")
 
     def __init__(self, hs):
         self._deactivate_account_handler = hs.get_deactivate_account_handler()
@@ -498,7 +523,7 @@ class DeactivateAccountRestServlet(RestServlet):
 
 
 class AccountValidityRenewServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/account_validity/validity$")
+    PATTERNS = admin_patterns("/account_validity/validity$")
 
     def __init__(self, hs):
         """
@@ -541,9 +566,7 @@ class ResetPasswordRestServlet(RestServlet):
             200 OK with empty object if success otherwise an error.
         """
 
-    PATTERNS = historical_admin_path_patterns(
-        "/reset_password/(?P<target_user_id>[^/]*)"
-    )
+    PATTERNS = admin_patterns("/reset_password/(?P<target_user_id>[^/]*)")
 
     def __init__(self, hs):
         self.store = hs.get_datastore()
@@ -585,13 +608,12 @@ class SearchUsersRestServlet(RestServlet):
             200 OK with json object {list[dict[str, Any]], count} or empty object.
     """
 
-    PATTERNS = historical_admin_path_patterns("/search_users/(?P<target_user_id>[^/]*)")
+    PATTERNS = admin_patterns("/search_users/(?P<target_user_id>[^/]*)")
 
     def __init__(self, hs):
         self.hs = hs
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
-        self.handlers = hs.get_handlers()
 
     async def on_GET(self, request, target_user_id):
         """Get request to search user table for specific users according to
@@ -612,7 +634,7 @@ class SearchUsersRestServlet(RestServlet):
         term = parse_string(request, "term", required=True)
         logger.info("term: %s ", term)
 
-        ret = await self.handlers.store.search_users(term)
+        ret = await self.store.search_users(term)
         return 200, ret
 
 
@@ -703,9 +725,163 @@ class UserMembershipRestServlet(RestServlet):
         if not self.is_mine(UserID.from_string(user_id)):
             raise SynapseError(400, "Can only lookup local users")
 
-        room_ids = await self.store.get_rooms_for_user(user_id)
-        if not room_ids:
-            raise NotFoundError("User not found")
+        user = await self.store.get_user_by_id(user_id)
+        if user is None:
+            raise NotFoundError("Unknown user")
 
+        room_ids = await self.store.get_rooms_for_user(user_id)
         ret = {"joined_rooms": list(room_ids), "total": len(room_ids)}
         return 200, ret
+
+
+class PushersRestServlet(RestServlet):
+    """
+    Gets information about all pushers for a specific `user_id`.
+
+    Example:
+        http://localhost:8008/_synapse/admin/v1/users/
+        @user:server/pushers
+
+    Returns:
+        pushers: Dictionary containing pushers information.
+        total: Number of pushers in dictonary `pushers`.
+    """
+
+    PATTERNS = admin_patterns("/users/(?P<user_id>[^/]*)/pushers$")
+
+    def __init__(self, hs):
+        self.is_mine = hs.is_mine
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+
+    async def on_GET(
+        self, request: SynapseRequest, user_id: str
+    ) -> Tuple[int, JsonDict]:
+        await assert_requester_is_admin(self.auth, request)
+
+        if not self.is_mine(UserID.from_string(user_id)):
+            raise SynapseError(400, "Can only lookup local users")
+
+        if not await self.store.get_user_by_id(user_id):
+            raise NotFoundError("User not found")
+
+        pushers = await self.store.get_pushers_by_user_id(user_id)
+
+        filtered_pushers = [
+            {k: v for k, v in p.items() if k in _GET_PUSHERS_ALLOWED_KEYS}
+            for p in pushers
+        ]
+
+        return 200, {"pushers": filtered_pushers, "total": len(filtered_pushers)}
+
+
+class UserMediaRestServlet(RestServlet):
+    """
+    Gets information about all uploaded local media for a specific `user_id`.
+
+    Example:
+        http://localhost:8008/_synapse/admin/v1/users/
+        @user:server/media
+
+    Args:
+        The parameters `from` and `limit` are required for pagination.
+        By default, a `limit` of 100 is used.
+    Returns:
+        A list of media and an integer representing the total number of
+        media that exist given for this user
+    """
+
+    PATTERNS = admin_patterns("/users/(?P<user_id>[^/]+)/media$")
+
+    def __init__(self, hs):
+        self.is_mine = hs.is_mine
+        self.auth = hs.get_auth()
+        self.store = hs.get_datastore()
+
+    async def on_GET(
+        self, request: SynapseRequest, user_id: str
+    ) -> Tuple[int, JsonDict]:
+        await assert_requester_is_admin(self.auth, request)
+
+        if not self.is_mine(UserID.from_string(user_id)):
+            raise SynapseError(400, "Can only lookup local users")
+
+        user = await self.store.get_user_by_id(user_id)
+        if user is None:
+            raise NotFoundError("Unknown user")
+
+        start = parse_integer(request, "from", default=0)
+        limit = parse_integer(request, "limit", default=100)
+
+        if start < 0:
+            raise SynapseError(
+                400,
+                "Query parameter from must be a string representing a positive integer.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        if limit < 0:
+            raise SynapseError(
+                400,
+                "Query parameter limit must be a string representing a positive integer.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        media, total = await self.store.get_local_media_by_user_paginate(
+            start, limit, user_id
+        )
+
+        ret = {"media": media, "total": total}
+        if (start + limit) < total:
+            ret["next_token"] = start + len(media)
+
+        return 200, ret
+
+
+class UserTokenRestServlet(RestServlet):
+    """An admin API for logging in as a user.
+
+    Example:
+
+        POST /_synapse/admin/v1/users/@test:example.com/login
+        {}
+
+        200 OK
+        {
+            "access_token": "<some_token>"
+        }
+    """
+
+    PATTERNS = admin_patterns("/users/(?P<user_id>[^/]*)/login$")
+
+    def __init__(self, hs: "HomeServer"):
+        self.hs = hs
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.auth_handler = hs.get_auth_handler()
+
+    async def on_POST(self, request, user_id):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+        auth_user = requester.user
+
+        if not self.hs.is_mine_id(user_id):
+            raise SynapseError(400, "Only local users can be logged in as")
+
+        body = parse_json_object_from_request(request, allow_empty_body=True)
+
+        valid_until_ms = body.get("valid_until_ms")
+        if valid_until_ms and not isinstance(valid_until_ms, int):
+            raise SynapseError(400, "'valid_until_ms' parameter must be an int")
+
+        if auth_user.to_string() == user_id:
+            raise SynapseError(400, "Cannot use admin API to login as self")
+
+        token = await self.auth_handler.get_access_token_for_user_id(
+            user_id=auth_user.to_string(),
+            device_id=None,
+            valid_until_ms=valid_until_ms,
+            puppets_user_id=user_id,
+        )
+
+        return 200, {"access_token": token}
diff --git a/synapse/rest/client/v1/directory.py b/synapse/rest/client/v1/directory.py
index faabeeb91c..e5af26b176 100644
--- a/synapse/rest/client/v1/directory.py
+++ b/synapse/rest/client/v1/directory.py
@@ -42,14 +42,13 @@ class ClientDirectoryServer(RestServlet):
     def __init__(self, hs):
         super().__init__()
         self.store = hs.get_datastore()
-        self.handlers = hs.get_handlers()
+        self.directory_handler = hs.get_directory_handler()
         self.auth = hs.get_auth()
 
     async def on_GET(self, request, room_alias):
         room_alias = RoomAlias.from_string(room_alias)
 
-        dir_handler = self.handlers.directory_handler
-        res = await dir_handler.get_association(room_alias)
+        res = await self.directory_handler.get_association(room_alias)
 
         return 200, res
 
@@ -79,19 +78,19 @@ class ClientDirectoryServer(RestServlet):
 
         requester = await self.auth.get_user_by_req(request)
 
-        await self.handlers.directory_handler.create_association(
+        await self.directory_handler.create_association(
             requester, room_alias, room_id, servers
         )
 
         return 200, {}
 
     async def on_DELETE(self, request, room_alias):
-        dir_handler = self.handlers.directory_handler
-
         try:
             service = self.auth.get_appservice_by_req(request)
             room_alias = RoomAlias.from_string(room_alias)
-            await dir_handler.delete_appservice_association(service, room_alias)
+            await self.directory_handler.delete_appservice_association(
+                service, room_alias
+            )
             logger.info(
                 "Application service at %s deleted alias %s",
                 service.url,
@@ -107,7 +106,7 @@ class ClientDirectoryServer(RestServlet):
 
         room_alias = RoomAlias.from_string(room_alias)
 
-        await dir_handler.delete_association(requester, room_alias)
+        await self.directory_handler.delete_association(requester, room_alias)
 
         logger.info(
             "User %s deleted alias %s", user.to_string(), room_alias.to_string()
@@ -122,7 +121,7 @@ class ClientDirectoryListServer(RestServlet):
     def __init__(self, hs):
         super().__init__()
         self.store = hs.get_datastore()
-        self.handlers = hs.get_handlers()
+        self.directory_handler = hs.get_directory_handler()
         self.auth = hs.get_auth()
 
     async def on_GET(self, request, room_id):
@@ -138,7 +137,7 @@ class ClientDirectoryListServer(RestServlet):
         content = parse_json_object_from_request(request)
         visibility = content.get("visibility", "public")
 
-        await self.handlers.directory_handler.edit_published_room_list(
+        await self.directory_handler.edit_published_room_list(
             requester, room_id, visibility
         )
 
@@ -147,7 +146,7 @@ class ClientDirectoryListServer(RestServlet):
     async def on_DELETE(self, request, room_id):
         requester = await self.auth.get_user_by_req(request)
 
-        await self.handlers.directory_handler.edit_published_room_list(
+        await self.directory_handler.edit_published_room_list(
             requester, room_id, "private"
         )
 
@@ -162,7 +161,7 @@ class ClientAppserviceDirectoryListServer(RestServlet):
     def __init__(self, hs):
         super().__init__()
         self.store = hs.get_datastore()
-        self.handlers = hs.get_handlers()
+        self.directory_handler = hs.get_directory_handler()
         self.auth = hs.get_auth()
 
     def on_PUT(self, request, network_id, room_id):
@@ -180,7 +179,7 @@ class ClientAppserviceDirectoryListServer(RestServlet):
                 403, "Only appservices can edit the appservice published room list"
             )
 
-        await self.handlers.directory_handler.edit_published_appservice_room_list(
+        await self.directory_handler.edit_published_appservice_room_list(
             requester.app_service.id, network_id, room_id, visibility
         )
 
diff --git a/synapse/rest/client/v1/events.py b/synapse/rest/client/v1/events.py
index 1ecb77aa26..6de4078290 100644
--- a/synapse/rest/client/v1/events.py
+++ b/synapse/rest/client/v1/events.py
@@ -67,9 +67,6 @@ class EventStreamRestServlet(RestServlet):
 
         return 200, chunk
 
-    def on_OPTIONS(self, request):
-        return 200, {}
-
 
 class EventRestServlet(RestServlet):
     PATTERNS = client_patterns("/events/(?P<event_id>[^/]*)$", v1=True)
diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 3d1693d7ac..d7ae148214 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -19,10 +19,6 @@ from typing import Awaitable, Callable, Dict, Optional
 from synapse.api.errors import Codes, LoginError, SynapseError
 from synapse.api.ratelimiting import Ratelimiter
 from synapse.appservice import ApplicationService
-from synapse.handlers.auth import (
-    convert_client_dict_legacy_fields_to_identifier,
-    login_id_phone_to_thirdparty,
-)
 from synapse.http.server import finish_request
 from synapse.http.servlet import (
     RestServlet,
@@ -33,7 +29,6 @@ from synapse.http.site import SynapseRequest
 from synapse.rest.client.v2_alpha._base import client_patterns
 from synapse.rest.well_known import WellKnownBuilder
 from synapse.types import JsonDict, UserID
-from synapse.util.threepids import canonicalise_email
 
 logger = logging.getLogger(__name__)
 
@@ -67,7 +62,6 @@ class LoginRestServlet(RestServlet):
 
         self.auth_handler = self.hs.get_auth_handler()
         self.registration_handler = hs.get_registration_handler()
-        self.handlers = hs.get_handlers()
         self._well_known_builder = WellKnownBuilder(hs)
         self._address_ratelimiter = Ratelimiter(
             clock=hs.get_clock(),
@@ -79,11 +73,6 @@ class LoginRestServlet(RestServlet):
             rate_hz=self.hs.config.rc_login_account.per_second,
             burst_count=self.hs.config.rc_login_account.burst_count,
         )
-        self._failed_attempts_ratelimiter = Ratelimiter(
-            clock=hs.get_clock(),
-            rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
-            burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
-        )
 
     def on_GET(self, request: SynapseRequest):
         flows = []
@@ -111,10 +100,9 @@ class LoginRestServlet(RestServlet):
             ({"type": t} for t in self.auth_handler.get_supported_login_types())
         )
 
-        return 200, {"flows": flows}
+        flows.append({"type": LoginRestServlet.APPSERVICE_TYPE})
 
-    def on_OPTIONS(self, request: SynapseRequest):
-        return 200, {}
+        return 200, {"flows": flows}
 
     async def on_POST(self, request: SynapseRequest):
         self._address_ratelimiter.ratelimit(request.getClientIP())
@@ -142,27 +130,31 @@ class LoginRestServlet(RestServlet):
             result["well_known"] = well_known_data
         return 200, result
 
-    def _get_qualified_user_id(self, identifier):
-        if identifier["type"] != "m.id.user":
-            raise SynapseError(400, "Unknown login identifier type")
-        if "user" not in identifier:
-            raise SynapseError(400, "User identifier is missing 'user' key")
-
-        if identifier["user"].startswith("@"):
-            return identifier["user"]
-        else:
-            return UserID(identifier["user"], self.hs.hostname).to_string()
-
     async def _do_appservice_login(
         self, login_submission: JsonDict, appservice: ApplicationService
     ):
-        logger.info(
-            "Got appservice login request with identifier: %r",
-            login_submission.get("identifier"),
-        )
+        identifier = login_submission.get("identifier")
+        logger.info("Got appservice login request with identifier: %r", identifier)
 
-        identifier = convert_client_dict_legacy_fields_to_identifier(login_submission)
-        qualified_user_id = self._get_qualified_user_id(identifier)
+        if not isinstance(identifier, dict):
+            raise SynapseError(
+                400, "Invalid identifier in login submission", Codes.INVALID_PARAM
+            )
+
+        # this login flow only supports identifiers of type "m.id.user".
+        if identifier.get("type") != "m.id.user":
+            raise SynapseError(
+                400, "Unknown login identifier type", Codes.INVALID_PARAM
+            )
+
+        user = identifier.get("user")
+        if not isinstance(user, str):
+            raise SynapseError(400, "Invalid user in identifier", Codes.INVALID_PARAM)
+
+        if user.startswith("@"):
+            qualified_user_id = user
+        else:
+            qualified_user_id = UserID(user, self.hs.hostname).to_string()
 
         if not appservice.is_interested_in_user(qualified_user_id):
             raise LoginError(403, "Invalid access_token", errcode=Codes.FORBIDDEN)
@@ -188,91 +180,9 @@ class LoginRestServlet(RestServlet):
             login_submission.get("address"),
             login_submission.get("user"),
         )
-        identifier = convert_client_dict_legacy_fields_to_identifier(login_submission)
-
-        # convert phone type identifiers to generic threepids
-        if identifier["type"] == "m.id.phone":
-            identifier = login_id_phone_to_thirdparty(identifier)
-
-        # convert threepid identifiers to user IDs
-        if identifier["type"] == "m.id.thirdparty":
-            address = identifier.get("address")
-            medium = identifier.get("medium")
-
-            if medium is None or address is None:
-                raise SynapseError(400, "Invalid thirdparty identifier")
-
-            # For emails, canonicalise the address.
-            # We store all email addresses canonicalised in the DB.
-            # (See add_threepid in synapse/handlers/auth.py)
-            if medium == "email":
-                try:
-                    address = canonicalise_email(address)
-                except ValueError as e:
-                    raise SynapseError(400, str(e))
-
-            # We also apply account rate limiting using the 3PID as a key, as
-            # otherwise using 3PID bypasses the ratelimiting based on user ID.
-            self._failed_attempts_ratelimiter.ratelimit((medium, address), update=False)
-
-            # Check for login providers that support 3pid login types
-            (
-                canonical_user_id,
-                callback_3pid,
-            ) = await self.auth_handler.check_password_provider_3pid(
-                medium, address, login_submission["password"]
-            )
-            if canonical_user_id:
-                # Authentication through password provider and 3pid succeeded
-
-                result = await self._complete_login(
-                    canonical_user_id, login_submission, callback_3pid
-                )
-                return result
-
-            # No password providers were able to handle this 3pid
-            # Check local store
-            user_id = await self.hs.get_datastore().get_user_id_by_threepid(
-                medium, address
-            )
-            if not user_id:
-                logger.warning(
-                    "unknown 3pid identifier medium %s, address %r", medium, address
-                )
-                # We mark that we've failed to log in here, as
-                # `check_password_provider_3pid` might have returned `None` due
-                # to an incorrect password, rather than the account not
-                # existing.
-                #
-                # If it returned None but the 3PID was bound then we won't hit
-                # this code path, which is fine as then the per-user ratelimit
-                # will kick in below.
-                self._failed_attempts_ratelimiter.can_do_action((medium, address))
-                raise LoginError(403, "", errcode=Codes.FORBIDDEN)
-
-            identifier = {"type": "m.id.user", "user": user_id}
-
-        # by this point, the identifier should be an m.id.user: if it's anything
-        # else, we haven't understood it.
-        qualified_user_id = self._get_qualified_user_id(identifier)
-
-        # Check if we've hit the failed ratelimit (but don't update it)
-        self._failed_attempts_ratelimiter.ratelimit(
-            qualified_user_id.lower(), update=False
+        canonical_user_id, callback = await self.auth_handler.validate_login(
+            login_submission, ratelimit=True
         )
-
-        try:
-            canonical_user_id, callback = await self.auth_handler.validate_login(
-                identifier["user"], login_submission
-            )
-        except LoginError:
-            # The user has failed to log in, so we need to update the rate
-            # limiter. Using `can_do_action` avoids us raising a ratelimit
-            # exception and masking the LoginError. The actual ratelimiting
-            # should have happened above.
-            self._failed_attempts_ratelimiter.can_do_action(qualified_user_id.lower())
-            raise
-
         result = await self._complete_login(
             canonical_user_id, login_submission, callback
         )
diff --git a/synapse/rest/client/v1/logout.py b/synapse/rest/client/v1/logout.py
index f792b50cdc..ad8cea49c6 100644
--- a/synapse/rest/client/v1/logout.py
+++ b/synapse/rest/client/v1/logout.py
@@ -30,9 +30,6 @@ class LogoutRestServlet(RestServlet):
         self._auth_handler = hs.get_auth_handler()
         self._device_handler = hs.get_device_handler()
 
-    def on_OPTIONS(self, request):
-        return 200, {}
-
     async def on_POST(self, request):
         requester = await self.auth.get_user_by_req(request, allow_expired=True)
 
@@ -58,9 +55,6 @@ class LogoutAllRestServlet(RestServlet):
         self._auth_handler = hs.get_auth_handler()
         self._device_handler = hs.get_device_handler()
 
-    def on_OPTIONS(self, request):
-        return 200, {}
-
     async def on_POST(self, request):
         requester = await self.auth.get_user_by_req(request, allow_expired=True)
         user_id = requester.user.to_string()
diff --git a/synapse/rest/client/v1/presence.py b/synapse/rest/client/v1/presence.py
index 4796cdac05..94bfe2d1b0 100644
--- a/synapse/rest/client/v1/presence.py
+++ b/synapse/rest/client/v1/presence.py
@@ -84,9 +84,6 @@ class PresenceStatusRestServlet(RestServlet):
 
         return 200, {}
 
-    def on_OPTIONS(self, request):
-        return 200, {}
-
 
 def register_servlets(hs, http_server):
     PresenceStatusRestServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v1/profile.py b/synapse/rest/client/v1/profile.py
index 204b2ec9e5..b5fa1cc464 100644
--- a/synapse/rest/client/v1/profile.py
+++ b/synapse/rest/client/v1/profile.py
@@ -61,7 +61,9 @@ class ProfileDisplaynameRestServlet(RestServlet):
         try:
             new_name = content["displayname"]
         except Exception:
-            return 400, "Unable to parse name"
+            raise SynapseError(
+                code=400, msg="Unable to parse name", errcode=Codes.BAD_JSON,
+            )
 
         await self.profile_handler.set_displayname(user, requester, new_name, is_admin)
 
diff --git a/synapse/rest/client/v1/push_rule.py b/synapse/rest/client/v1/push_rule.py
index f9eecb7cf5..241e535917 100644
--- a/synapse/rest/client/v1/push_rule.py
+++ b/synapse/rest/client/v1/push_rule.py
@@ -155,9 +155,6 @@ class PushRuleRestServlet(RestServlet):
         else:
             raise UnrecognizedRequestError()
 
-    def on_OPTIONS(self, request, path):
-        return 200, {}
-
     def notify_user(self, user_id):
         stream_id = self.store.get_max_push_rules_stream_id()
         self.notifier.on_new_event("push_rules_key", stream_id, users=[user_id])
diff --git a/synapse/rest/client/v1/pusher.py b/synapse/rest/client/v1/pusher.py
index 28dabf1c7a..8fe83f321a 100644
--- a/synapse/rest/client/v1/pusher.py
+++ b/synapse/rest/client/v1/pusher.py
@@ -60,9 +60,6 @@ class PushersRestServlet(RestServlet):
 
         return 200, {"pushers": filtered_pushers}
 
-    def on_OPTIONS(self, _):
-        return 200, {}
-
 
 class PushersSetRestServlet(RestServlet):
     PATTERNS = client_patterns("/pushers/set$", v1=True)
@@ -140,9 +137,6 @@ class PushersSetRestServlet(RestServlet):
 
         return 200, {}
 
-    def on_OPTIONS(self, _):
-        return 200, {}
-
 
 class PushersRemoveRestServlet(RestServlet):
     """
@@ -182,9 +176,6 @@ class PushersRemoveRestServlet(RestServlet):
         )
         return None
 
-    def on_OPTIONS(self, _):
-        return 200, {}
-
 
 def register_servlets(hs, http_server):
     PushersRestServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index b421fe855e..0c658f120e 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -18,7 +18,7 @@
 
 import logging
 import re
-from typing import List, Optional
+from typing import TYPE_CHECKING, List, Optional
 from urllib import parse as urlparse
 
 from synapse.api.constants import EventTypes, Membership
@@ -48,8 +48,7 @@ from synapse.types import RoomAlias, RoomID, StreamToken, ThirdPartyInstanceID,
 from synapse.util import json_decoder
 from synapse.util.stringutils import random_string
 
-MYPY = False
-if MYPY:
+if TYPE_CHECKING:
     import synapse.server
 
 logger = logging.getLogger(__name__)
@@ -72,20 +71,6 @@ class RoomCreateRestServlet(TransactionRestServlet):
     def register(self, http_server):
         PATTERNS = "/createRoom"
         register_txn_path(self, PATTERNS, http_server)
-        # define CORS for all of /rooms in RoomCreateRestServlet for simplicity
-        http_server.register_paths(
-            "OPTIONS",
-            client_patterns("/rooms(?:/.*)?$", v1=True),
-            self.on_OPTIONS,
-            self.__class__.__name__,
-        )
-        # define CORS for /createRoom[/txnid]
-        http_server.register_paths(
-            "OPTIONS",
-            client_patterns("/createRoom(?:/.*)?$", v1=True),
-            self.on_OPTIONS,
-            self.__class__.__name__,
-        )
 
     def on_PUT(self, request, txn_id):
         set_tag("txn_id", txn_id)
@@ -104,15 +89,11 @@ class RoomCreateRestServlet(TransactionRestServlet):
         user_supplied_config = parse_json_object_from_request(request)
         return user_supplied_config
 
-    def on_OPTIONS(self, request):
-        return 200, {}
-
 
 # TODO: Needs unit testing for generic events
 class RoomStateEventRestServlet(TransactionRestServlet):
     def __init__(self, hs):
         super().__init__(hs)
-        self.handlers = hs.get_handlers()
         self.event_creation_handler = hs.get_event_creation_handler()
         self.room_member_handler = hs.get_room_member_handler()
         self.message_handler = hs.get_message_handler()
@@ -799,7 +780,6 @@ class RoomMembershipRestServlet(TransactionRestServlet):
 class RoomRedactEventRestServlet(TransactionRestServlet):
     def __init__(self, hs):
         super().__init__(hs)
-        self.handlers = hs.get_handlers()
         self.event_creation_handler = hs.get_event_creation_handler()
         self.auth = hs.get_auth()
 
@@ -904,7 +884,7 @@ class RoomAliasListServlet(RestServlet):
     def __init__(self, hs: "synapse.server.HomeServer"):
         super().__init__()
         self.auth = hs.get_auth()
-        self.directory_handler = hs.get_handlers().directory_handler
+        self.directory_handler = hs.get_directory_handler()
 
     async def on_GET(self, request, room_id):
         requester = await self.auth.get_user_by_req(request)
@@ -921,7 +901,7 @@ class SearchRestServlet(RestServlet):
 
     def __init__(self, hs):
         super().__init__()
-        self.handlers = hs.get_handlers()
+        self.search_handler = hs.get_search_handler()
         self.auth = hs.get_auth()
 
     async def on_POST(self, request):
@@ -930,9 +910,7 @@ class SearchRestServlet(RestServlet):
         content = parse_json_object_from_request(request)
 
         batch = parse_string(request, "next_batch")
-        results = await self.handlers.search_handler.search(
-            requester.user, content, batch
-        )
+        results = await self.search_handler.search(requester.user, content, batch)
 
         return 200, results
 
diff --git a/synapse/rest/client/v1/voip.py b/synapse/rest/client/v1/voip.py
index b8d491ca5c..d07ca2c47c 100644
--- a/synapse/rest/client/v1/voip.py
+++ b/synapse/rest/client/v1/voip.py
@@ -69,9 +69,6 @@ class VoipRestServlet(RestServlet):
             },
         )
 
-    def on_OPTIONS(self, request):
-        return 200, {}
-
 
 def register_servlets(hs, http_server):
     VoipRestServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 1320aad8f6..8e4a01a7e8 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -39,6 +39,7 @@ from synapse.http.servlet import (
     parse_json_object_from_request,
     parse_string,
 )
+from synapse.metrics import threepid_send_requests
 from synapse.push.mailer import Mailer
 from synapse.types import UserID
 from synapse.util.msisdn import phone_number_to_msisdn
@@ -58,7 +59,7 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
         self.hs = hs
         self.datastore = hs.get_datastore()
         self.config = hs.config
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
 
         if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
             self.mailer = Mailer(
@@ -116,7 +117,7 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
                 # look like we did something.
-                await self.hs.clock.sleep(random.randint(1, 10) / 10)
+                await self.hs.get_clock().sleep(random.randint(1, 10) / 10)
                 return 200, {"sid": random_string(16)}
 
             raise SynapseError(400, "Email not found", Codes.THREEPID_NOT_FOUND)
@@ -145,6 +146,10 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
             # Wrap the session id in a JSON object
             ret = {"sid": sid}
 
+        threepid_send_requests.labels(type="email", reason="password_reset").observe(
+            send_attempt
+        )
+
         return 200, ret
 
 
@@ -354,7 +359,7 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
         super().__init__()
         self.hs = hs
         self.config = hs.config
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
         self.store = self.hs.get_datastore()
 
         if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
@@ -412,7 +417,7 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
                 # look like we did something.
-                await self.hs.clock.sleep(random.randint(1, 10) / 10)
+                await self.hs.get_clock().sleep(random.randint(1, 10) / 10)
                 return 200, {"sid": random_string(16)}
 
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
@@ -441,6 +446,10 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
             # Wrap the session id in a JSON object
             ret = {"sid": sid}
 
+        threepid_send_requests.labels(type="email", reason="add_threepid").observe(
+            send_attempt
+        )
+
         return 200, ret
 
 
@@ -451,7 +460,7 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
         self.hs = hs
         super().__init__()
         self.store = self.hs.get_datastore()
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
 
     async def on_POST(self, request):
         body = parse_json_object_from_request(request)
@@ -487,7 +496,7 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
                 # look like we did something.
-                await self.hs.clock.sleep(random.randint(1, 10) / 10)
+                await self.hs.get_clock().sleep(random.randint(1, 10) / 10)
                 return 200, {"sid": random_string(16)}
 
             raise SynapseError(400, "MSISDN is already in use", Codes.THREEPID_IN_USE)
@@ -511,6 +520,10 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
             next_link,
         )
 
+        threepid_send_requests.labels(type="msisdn", reason="add_threepid").observe(
+            send_attempt
+        )
+
         return 200, ret
 
 
@@ -601,7 +614,7 @@ class AddThreepidMsisdnSubmitTokenServlet(RestServlet):
         self.config = hs.config
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
 
     async def on_POST(self, request):
         if not self.config.account_threepid_delegate_msisdn:
@@ -631,7 +644,7 @@ class ThreepidRestServlet(RestServlet):
     def __init__(self, hs):
         super().__init__()
         self.hs = hs
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
         self.auth = hs.get_auth()
         self.auth_handler = hs.get_auth_handler()
         self.datastore = hs.get_datastore()
@@ -734,7 +747,7 @@ class ThreepidAddRestServlet(RestServlet):
     def __init__(self, hs):
         super().__init__()
         self.hs = hs
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
         self.auth = hs.get_auth()
         self.auth_handler = hs.get_auth_handler()
         self.http_client = hs.get_simple_http_client()
@@ -807,7 +820,7 @@ class ThreepidBindRestServlet(RestServlet):
     def __init__(self, hs):
         super().__init__()
         self.hs = hs
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
         self.auth = hs.get_auth()
 
     async def on_POST(self, request):
@@ -836,7 +849,7 @@ class ThreepidUnbindRestServlet(RestServlet):
     def __init__(self, hs):
         super().__init__()
         self.hs = hs
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
         self.auth = hs.get_auth()
         self.datastore = self.hs.get_datastore()
 
@@ -925,7 +938,7 @@ class ThreepidLookupRestServlet(RestServlet):
     def __init__(self, hs):
         super(ThreepidLookupRestServlet, self).__init__()
         self.auth = hs.get_auth()
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
 
     async def on_GET(self, request):
         """Proxy a /_matrix/identity/api/v1/lookup request to an identity
@@ -955,7 +968,7 @@ class ThreepidBulkLookupRestServlet(RestServlet):
     def __init__(self, hs):
         super(ThreepidBulkLookupRestServlet, self).__init__()
         self.auth = hs.get_auth()
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
 
     async def on_POST(self, request):
         """Proxy a /_matrix/identity/api/v1/bulk_lookup request to an identity
diff --git a/synapse/rest/client/v2_alpha/auth.py b/synapse/rest/client/v2_alpha/auth.py
index 5fbfae5991..fab077747f 100644
--- a/synapse/rest/client/v2_alpha/auth.py
+++ b/synapse/rest/client/v2_alpha/auth.py
@@ -176,9 +176,6 @@ class AuthRestServlet(RestServlet):
         respond_with_html(request, 200, html)
         return None
 
-    def on_OPTIONS(self, _):
-        return 200, {}
-
 
 def register_servlets(hs, http_server):
     AuthRestServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v2_alpha/devices.py b/synapse/rest/client/v2_alpha/devices.py
index 7e174de692..af117cb27c 100644
--- a/synapse/rest/client/v2_alpha/devices.py
+++ b/synapse/rest/client/v2_alpha/devices.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
+# Copyright 2020 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -21,6 +22,7 @@ from synapse.http.servlet import (
     assert_params_in_dict,
     parse_json_object_from_request,
 )
+from synapse.http.site import SynapseRequest
 
 from ._base import client_patterns, interactive_auth_handler
 
@@ -151,7 +153,139 @@ class DeviceRestServlet(RestServlet):
         return 200, {}
 
 
+class DehydratedDeviceServlet(RestServlet):
+    """Retrieve or store a dehydrated device.
+
+    GET /org.matrix.msc2697.v2/dehydrated_device
+
+    HTTP/1.1 200 OK
+    Content-Type: application/json
+
+    {
+      "device_id": "dehydrated_device_id",
+      "device_data": {
+        "algorithm": "org.matrix.msc2697.v1.dehydration.v1.olm",
+        "account": "dehydrated_device"
+      }
+    }
+
+    PUT /org.matrix.msc2697/dehydrated_device
+    Content-Type: application/json
+
+    {
+      "device_data": {
+        "algorithm": "org.matrix.msc2697.v1.dehydration.v1.olm",
+        "account": "dehydrated_device"
+      }
+    }
+
+    HTTP/1.1 200 OK
+    Content-Type: application/json
+
+    {
+      "device_id": "dehydrated_device_id"
+    }
+
+    """
+
+    PATTERNS = client_patterns("/org.matrix.msc2697.v2/dehydrated_device", releases=())
+
+    def __init__(self, hs):
+        super().__init__()
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.device_handler = hs.get_device_handler()
+
+    async def on_GET(self, request: SynapseRequest):
+        requester = await self.auth.get_user_by_req(request)
+        dehydrated_device = await self.device_handler.get_dehydrated_device(
+            requester.user.to_string()
+        )
+        if dehydrated_device is not None:
+            (device_id, device_data) = dehydrated_device
+            result = {"device_id": device_id, "device_data": device_data}
+            return (200, result)
+        else:
+            raise errors.NotFoundError("No dehydrated device available")
+
+    async def on_PUT(self, request: SynapseRequest):
+        submission = parse_json_object_from_request(request)
+        requester = await self.auth.get_user_by_req(request)
+
+        if "device_data" not in submission:
+            raise errors.SynapseError(
+                400, "device_data missing", errcode=errors.Codes.MISSING_PARAM,
+            )
+        elif not isinstance(submission["device_data"], dict):
+            raise errors.SynapseError(
+                400,
+                "device_data must be an object",
+                errcode=errors.Codes.INVALID_PARAM,
+            )
+
+        device_id = await self.device_handler.store_dehydrated_device(
+            requester.user.to_string(),
+            submission["device_data"],
+            submission.get("initial_device_display_name", None),
+        )
+        return 200, {"device_id": device_id}
+
+
+class ClaimDehydratedDeviceServlet(RestServlet):
+    """Claim a dehydrated device.
+
+    POST /org.matrix.msc2697.v2/dehydrated_device/claim
+    Content-Type: application/json
+
+    {
+      "device_id": "dehydrated_device_id"
+    }
+
+    HTTP/1.1 200 OK
+    Content-Type: application/json
+
+    {
+      "success": true,
+    }
+
+    """
+
+    PATTERNS = client_patterns(
+        "/org.matrix.msc2697.v2/dehydrated_device/claim", releases=()
+    )
+
+    def __init__(self, hs):
+        super().__init__()
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.device_handler = hs.get_device_handler()
+
+    async def on_POST(self, request: SynapseRequest):
+        requester = await self.auth.get_user_by_req(request)
+
+        submission = parse_json_object_from_request(request)
+
+        if "device_id" not in submission:
+            raise errors.SynapseError(
+                400, "device_id missing", errcode=errors.Codes.MISSING_PARAM,
+            )
+        elif not isinstance(submission["device_id"], str):
+            raise errors.SynapseError(
+                400, "device_id must be a string", errcode=errors.Codes.INVALID_PARAM,
+            )
+
+        result = await self.device_handler.rehydrate_device(
+            requester.user.to_string(),
+            self.auth.get_access_token_from_request(request),
+            submission["device_id"],
+        )
+
+        return (200, result)
+
+
 def register_servlets(hs, http_server):
     DeleteDevicesRestServlet(hs).register(http_server)
     DevicesRestServlet(hs).register(http_server)
     DeviceRestServlet(hs).register(http_server)
+    DehydratedDeviceServlet(hs).register(http_server)
+    ClaimDehydratedDeviceServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v2_alpha/keys.py b/synapse/rest/client/v2_alpha/keys.py
index 55c4606569..b91996c738 100644
--- a/synapse/rest/client/v2_alpha/keys.py
+++ b/synapse/rest/client/v2_alpha/keys.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
 # Copyright 2019 New Vector Ltd
+# Copyright 2020 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -67,6 +68,7 @@ class KeyUploadServlet(RestServlet):
         super().__init__()
         self.auth = hs.get_auth()
         self.e2e_keys_handler = hs.get_e2e_keys_handler()
+        self.device_handler = hs.get_device_handler()
 
     @trace(opname="upload_keys")
     async def on_POST(self, request, device_id):
@@ -75,23 +77,28 @@ class KeyUploadServlet(RestServlet):
         body = parse_json_object_from_request(request)
 
         if device_id is not None:
-            # passing the device_id here is deprecated; however, we allow it
-            # for now for compatibility with older clients.
+            # Providing the device_id should only be done for setting keys
+            # for dehydrated devices; however, we allow it for any device for
+            # compatibility with older clients.
             if requester.device_id is not None and device_id != requester.device_id:
-                set_tag("error", True)
-                log_kv(
-                    {
-                        "message": "Client uploading keys for a different device",
-                        "logged_in_id": requester.device_id,
-                        "key_being_uploaded": device_id,
-                    }
-                )
-                logger.warning(
-                    "Client uploading keys for a different device "
-                    "(logged in as %s, uploading for %s)",
-                    requester.device_id,
-                    device_id,
+                dehydrated_device = await self.device_handler.get_dehydrated_device(
+                    user_id
                 )
+                if dehydrated_device is not None and device_id != dehydrated_device[0]:
+                    set_tag("error", True)
+                    log_kv(
+                        {
+                            "message": "Client uploading keys for a different device",
+                            "logged_in_id": requester.device_id,
+                            "key_being_uploaded": device_id,
+                        }
+                    )
+                    logger.warning(
+                        "Client uploading keys for a different device "
+                        "(logged in as %s, uploading for %s)",
+                        requester.device_id,
+                        device_id,
+                    )
         else:
             device_id = requester.device_id
 
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 91ea76bc20..36807458de 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -47,6 +47,7 @@ from synapse.http.servlet import (
     parse_json_object_from_request,
     parse_string,
 )
+from synapse.metrics import threepid_send_requests
 from synapse.push.mailer import Mailer
 from synapse.util.msisdn import phone_number_to_msisdn
 from synapse.util.ratelimitutils import FederationRateLimiter
@@ -80,7 +81,7 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
         """
         super().__init__()
         self.hs = hs
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
         self.config = hs.config
 
         if self.hs.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
@@ -136,7 +137,7 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
                 # look like we did something.
-                await self.hs.clock.sleep(random.randint(1, 10) / 10)
+                await self.hs.get_clock().sleep(random.randint(1, 10) / 10)
                 return 200, {"sid": random_string(16)}
 
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
@@ -165,6 +166,10 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
             # Wrap the session id in a JSON object
             ret = {"sid": sid}
 
+        threepid_send_requests.labels(type="email", reason="register").observe(
+            send_attempt
+        )
+
         return 200, ret
 
 
@@ -178,7 +183,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
         """
         super().__init__()
         self.hs = hs
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
 
     async def on_POST(self, request):
         body = parse_json_object_from_request(request)
@@ -213,7 +218,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
                 # comments for request_token_inhibit_3pid_errors.
                 # Also wait for some random amount of time between 100ms and 1s to make it
                 # look like we did something.
-                await self.hs.clock.sleep(random.randint(1, 10) / 10)
+                await self.hs.get_clock().sleep(random.randint(1, 10) / 10)
                 return 200, {"sid": random_string(16)}
 
             raise SynapseError(
@@ -238,6 +243,10 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
             next_link,
         )
 
+        threepid_send_requests.labels(type="msisdn", reason="register").observe(
+            send_attempt
+        )
+
         return 200, ret
 
 
@@ -368,7 +377,7 @@ class RegisterRestServlet(RestServlet):
         self.store = hs.get_datastore()
         self.auth_handler = hs.get_auth_handler()
         self.registration_handler = hs.get_registration_handler()
-        self.identity_handler = hs.get_handlers().identity_handler
+        self.identity_handler = hs.get_identity_handler()
         self.room_member_handler = hs.get_room_member_handler()
         self.macaroon_gen = hs.get_macaroon_generator()
         self.ratelimiter = hs.get_registration_ratelimiter()
@@ -491,6 +500,7 @@ class RegisterRestServlet(RestServlet):
         # Check if the user-interactive authentication flows are complete, if
         # not this will raise a user-interactive auth error.
         try:
+            print("Trying")
             auth_result, params, session_id = await self.auth_handler.check_ui_auth(
                 self._registration_flows,
                 request,
@@ -718,9 +728,6 @@ class RegisterRestServlet(RestServlet):
 
         return 200, return_dict
 
-    def on_OPTIONS(self, _):
-        return 200, {}
-
     async def _do_appservice_registration(
         self, username, password, display_name, as_token, body
     ):
@@ -733,7 +740,6 @@ class RegisterRestServlet(RestServlet):
             # In mainline hashing of the password was moved further on in the registration
             # flow, but we need it here for the AS use-case of shadow servers
             password = await self.auth_handler.hash(password)
-
         user_id = await self.registration_handler.appservice_register(
             username, as_token, password, display_name
         )
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index 6779df952f..8e52e4cca4 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -171,6 +171,7 @@ class SyncRestServlet(RestServlet):
         )
         with context:
             sync_result = await self.sync_handler.wait_for_sync_for_user(
+                requester,
                 sync_config,
                 since_token=since_token,
                 timeout=timeout,
@@ -236,6 +237,7 @@ class SyncRestServlet(RestServlet):
                 "leave": sync_result.groups.leave,
             },
             "device_one_time_keys_count": sync_result.device_one_time_keys_count,
+            "org.matrix.msc2732.device_unused_fallback_key_types": sync_result.device_unused_fallback_key_types,
             "next_batch": await sync_result.next_batch.to_string(self.store),
         }
 
diff --git a/synapse/rest/key/v2/local_key_resource.py b/synapse/rest/key/v2/local_key_resource.py
index c16280f668..d8e8e48c1c 100644
--- a/synapse/rest/key/v2/local_key_resource.py
+++ b/synapse/rest/key/v2/local_key_resource.py
@@ -66,7 +66,7 @@ class LocalKey(Resource):
 
     def __init__(self, hs):
         self.config = hs.config
-        self.clock = hs.clock
+        self.clock = hs.get_clock()
         self.update_response_body(self.clock.time_msec())
         Resource.__init__(self)
 
diff --git a/synapse/rest/media/v1/_base.py b/synapse/rest/media/v1/_base.py
index 6568e61829..67aa993f19 100644
--- a/synapse/rest/media/v1/_base.py
+++ b/synapse/rest/media/v1/_base.py
@@ -213,6 +213,12 @@ async def respond_with_responder(
         file_size (int|None): Size in bytes of the media. If not known it should be None
         upload_name (str|None): The name of the requested file, if any.
     """
+    if request._disconnected:
+        logger.warning(
+            "Not sending response to request %s, already disconnected.", request
+        )
+        return
+
     if not responder:
         respond_404(request)
         return
diff --git a/synapse/rest/media/v1/filepath.py b/synapse/rest/media/v1/filepath.py
index 7447eeaebe..9e079f672f 100644
--- a/synapse/rest/media/v1/filepath.py
+++ b/synapse/rest/media/v1/filepath.py
@@ -69,6 +69,23 @@ class MediaFilePaths:
 
     local_media_thumbnail = _wrap_in_base_path(local_media_thumbnail_rel)
 
+    def local_media_thumbnail_dir(self, media_id: str) -> str:
+        """
+        Retrieve the local store path of thumbnails of a given media_id
+
+        Args:
+            media_id: The media ID to query.
+        Returns:
+            Path of local_thumbnails from media_id
+        """
+        return os.path.join(
+            self.base_path,
+            "local_thumbnails",
+            media_id[0:2],
+            media_id[2:4],
+            media_id[4:],
+        )
+
     def remote_media_filepath_rel(self, server_name, file_id):
         return os.path.join(
             "remote_content", server_name, file_id[0:2], file_id[2:4], file_id[4:]
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index e1192b47cd..9cac74ebd8 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -18,7 +18,7 @@ import errno
 import logging
 import os
 import shutil
-from typing import IO, Dict, Optional, Tuple
+from typing import IO, Dict, List, Optional, Tuple
 
 import twisted.internet.error
 import twisted.web.http
@@ -305,15 +305,12 @@ class MediaRepository:
         # file_id is the ID we use to track the file locally. If we've already
         # seen the file then reuse the existing ID, otherwise genereate a new
         # one.
-        if media_info:
-            file_id = media_info["filesystem_id"]
-        else:
-            file_id = random_string(24)
-
-        file_info = FileInfo(server_name, file_id)
 
         # If we have an entry in the DB, try and look for it
         if media_info:
+            file_id = media_info["filesystem_id"]
+            file_info = FileInfo(server_name, file_id)
+
             if media_info["quarantined_by"]:
                 logger.info("Media is quarantined")
                 raise NotFoundError()
@@ -324,14 +321,34 @@ class MediaRepository:
 
         # Failed to find the file anywhere, lets download it.
 
-        media_info = await self._download_remote_file(server_name, media_id, file_id)
+        try:
+            media_info = await self._download_remote_file(server_name, media_id,)
+        except SynapseError:
+            raise
+        except Exception as e:
+            # An exception may be because we downloaded media in another
+            # process, so let's check if we magically have the media.
+            media_info = await self.store.get_cached_remote_media(server_name, media_id)
+            if not media_info:
+                raise e
+
+        file_id = media_info["filesystem_id"]
+        file_info = FileInfo(server_name, file_id)
+
+        # We generate thumbnails even if another process downloaded the media
+        # as a) it's conceivable that the other download request dies before it
+        # generates thumbnails, but mainly b) we want to be sure the thumbnails
+        # have finished being generated before responding to the client,
+        # otherwise they'll request thumbnails and get a 404 if they're not
+        # ready yet.
+        await self._generate_thumbnails(
+            server_name, media_id, file_id, media_info["media_type"]
+        )
 
         responder = await self.media_storage.fetch_media(file_info)
         return responder, media_info
 
-    async def _download_remote_file(
-        self, server_name: str, media_id: str, file_id: str
-    ) -> dict:
+    async def _download_remote_file(self, server_name: str, media_id: str,) -> dict:
         """Attempt to download the remote file from the given server name,
         using the given file_id as the local id.
 
@@ -346,6 +363,8 @@ class MediaRepository:
             The media info of the file.
         """
 
+        file_id = random_string(24)
+
         file_info = FileInfo(server_name=server_name, file_id=file_id)
 
         with self.media_storage.store_into_file(file_info) as (f, fname, finish):
@@ -401,22 +420,32 @@ class MediaRepository:
 
             await finish()
 
-        media_type = headers[b"Content-Type"][0].decode("ascii")
-        upload_name = get_filename_from_headers(headers)
-        time_now_ms = self.clock.time_msec()
+            media_type = headers[b"Content-Type"][0].decode("ascii")
+            upload_name = get_filename_from_headers(headers)
+            time_now_ms = self.clock.time_msec()
+
+            # Multiple remote media download requests can race (when using
+            # multiple media repos), so this may throw a violation constraint
+            # exception. If it does we'll delete the newly downloaded file from
+            # disk (as we're in the ctx manager).
+            #
+            # However: we've already called `finish()` so we may have also
+            # written to the storage providers. This is preferable to the
+            # alternative where we call `finish()` *after* this, where we could
+            # end up having an entry in the DB but fail to write the files to
+            # the storage providers.
+            await self.store.store_cached_remote_media(
+                origin=server_name,
+                media_id=media_id,
+                media_type=media_type,
+                time_now_ms=self.clock.time_msec(),
+                upload_name=upload_name,
+                media_length=length,
+                filesystem_id=file_id,
+            )
 
         logger.info("Stored remote media in file %r", fname)
 
-        await self.store.store_cached_remote_media(
-            origin=server_name,
-            media_id=media_id,
-            media_type=media_type,
-            time_now_ms=self.clock.time_msec(),
-            upload_name=upload_name,
-            media_length=length,
-            filesystem_id=file_id,
-        )
-
         media_info = {
             "media_type": media_type,
             "media_length": length,
@@ -425,8 +454,6 @@ class MediaRepository:
             "filesystem_id": file_id,
         }
 
-        await self._generate_thumbnails(server_name, media_id, file_id, media_type)
-
         return media_info
 
     def _get_thumbnail_requirements(self, media_type):
@@ -692,42 +719,60 @@ class MediaRepository:
             if not t_byte_source:
                 continue
 
-            try:
-                file_info = FileInfo(
-                    server_name=server_name,
-                    file_id=file_id,
-                    thumbnail=True,
-                    thumbnail_width=t_width,
-                    thumbnail_height=t_height,
-                    thumbnail_method=t_method,
-                    thumbnail_type=t_type,
-                    url_cache=url_cache,
-                )
+            file_info = FileInfo(
+                server_name=server_name,
+                file_id=file_id,
+                thumbnail=True,
+                thumbnail_width=t_width,
+                thumbnail_height=t_height,
+                thumbnail_method=t_method,
+                thumbnail_type=t_type,
+                url_cache=url_cache,
+            )
 
-                output_path = await self.media_storage.store_file(
-                    t_byte_source, file_info
-                )
-            finally:
-                t_byte_source.close()
+            with self.media_storage.store_into_file(file_info) as (f, fname, finish):
+                try:
+                    await self.media_storage.write_to_file(t_byte_source, f)
+                    await finish()
+                finally:
+                    t_byte_source.close()
 
-            t_len = os.path.getsize(output_path)
+                t_len = os.path.getsize(fname)
 
-            # Write to database
-            if server_name:
-                await self.store.store_remote_media_thumbnail(
-                    server_name,
-                    media_id,
-                    file_id,
-                    t_width,
-                    t_height,
-                    t_type,
-                    t_method,
-                    t_len,
-                )
-            else:
-                await self.store.store_local_thumbnail(
-                    media_id, t_width, t_height, t_type, t_method, t_len
-                )
+                # Write to database
+                if server_name:
+                    # Multiple remote media download requests can race (when
+                    # using multiple media repos), so this may throw a violation
+                    # constraint exception. If it does we'll delete the newly
+                    # generated thumbnail from disk (as we're in the ctx
+                    # manager).
+                    #
+                    # However: we've already called `finish()` so we may have
+                    # also written to the storage providers. This is preferable
+                    # to the alternative where we call `finish()` *after* this,
+                    # where we could end up having an entry in the DB but fail
+                    # to write the files to the storage providers.
+                    try:
+                        await self.store.store_remote_media_thumbnail(
+                            server_name,
+                            media_id,
+                            file_id,
+                            t_width,
+                            t_height,
+                            t_type,
+                            t_method,
+                            t_len,
+                        )
+                    except Exception as e:
+                        thumbnail_exists = await self.store.get_remote_media_thumbnail(
+                            server_name, media_id, t_width, t_height, t_type,
+                        )
+                        if not thumbnail_exists:
+                            raise e
+                else:
+                    await self.store.store_local_thumbnail(
+                        media_id, t_width, t_height, t_type, t_method, t_len
+                    )
 
         return {"width": m_width, "height": m_height}
 
@@ -767,6 +812,76 @@ class MediaRepository:
 
         return {"deleted": deleted}
 
+    async def delete_local_media(self, media_id: str) -> Tuple[List[str], int]:
+        """
+        Delete the given local or remote media ID from this server
+
+        Args:
+            media_id: The media ID to delete.
+        Returns:
+            A tuple of (list of deleted media IDs, total deleted media IDs).
+        """
+        return await self._remove_local_media_from_disk([media_id])
+
+    async def delete_old_local_media(
+        self, before_ts: int, size_gt: int = 0, keep_profiles: bool = True,
+    ) -> Tuple[List[str], int]:
+        """
+        Delete local or remote media from this server by size and timestamp. Removes
+        media files, any thumbnails and cached URLs.
+
+        Args:
+            before_ts: Unix timestamp in ms.
+                       Files that were last used before this timestamp will be deleted
+            size_gt: Size of the media in bytes. Files that are larger will be deleted
+            keep_profiles: Switch to delete also files that are still used in image data
+                           (e.g user profile, room avatar)
+                           If false these files will be deleted
+        Returns:
+            A tuple of (list of deleted media IDs, total deleted media IDs).
+        """
+        old_media = await self.store.get_local_media_before(
+            before_ts, size_gt, keep_profiles,
+        )
+        return await self._remove_local_media_from_disk(old_media)
+
+    async def _remove_local_media_from_disk(
+        self, media_ids: List[str]
+    ) -> Tuple[List[str], int]:
+        """
+        Delete local or remote media from this server. Removes media files,
+        any thumbnails and cached URLs.
+
+        Args:
+            media_ids: List of media_id to delete
+        Returns:
+            A tuple of (list of deleted media IDs, total deleted media IDs).
+        """
+        removed_media = []
+        for media_id in media_ids:
+            logger.info("Deleting media with ID '%s'", media_id)
+            full_path = self.filepaths.local_media_filepath(media_id)
+            try:
+                os.remove(full_path)
+            except OSError as e:
+                logger.warning("Failed to remove file: %r: %s", full_path, e)
+                if e.errno == errno.ENOENT:
+                    pass
+                else:
+                    continue
+
+            thumbnail_dir = self.filepaths.local_media_thumbnail_dir(media_id)
+            shutil.rmtree(thumbnail_dir, ignore_errors=True)
+
+            await self.store.delete_remote_media(self.server_name, media_id)
+
+            await self.store.delete_url_cache((media_id,))
+            await self.store.delete_url_cache_media((media_id,))
+
+            removed_media.append(media_id)
+
+        return removed_media, len(removed_media)
+
 
 class MediaRepositoryResource(Resource):
     """File uploading and downloading.
diff --git a/synapse/rest/media/v1/media_storage.py b/synapse/rest/media/v1/media_storage.py
index a9586fb0b7..268e0c8f50 100644
--- a/synapse/rest/media/v1/media_storage.py
+++ b/synapse/rest/media/v1/media_storage.py
@@ -52,6 +52,7 @@ class MediaStorage:
         storage_providers: Sequence["StorageProviderWrapper"],
     ):
         self.hs = hs
+        self.reactor = hs.get_reactor()
         self.local_media_directory = local_media_directory
         self.filepaths = filepaths
         self.storage_providers = storage_providers
@@ -70,13 +71,16 @@ class MediaStorage:
 
         with self.store_into_file(file_info) as (f, fname, finish_cb):
             # Write to the main repository
-            await defer_to_thread(
-                self.hs.get_reactor(), _write_file_synchronously, source, f
-            )
+            await self.write_to_file(source, f)
             await finish_cb()
 
         return fname
 
+    async def write_to_file(self, source: IO, output: IO):
+        """Asynchronously write the `source` to `output`.
+        """
+        await defer_to_thread(self.reactor, _write_file_synchronously, source, output)
+
     @contextlib.contextmanager
     def store_into_file(self, file_info: FileInfo):
         """Context manager used to get a file like object to write into, as
@@ -112,14 +116,20 @@ class MediaStorage:
 
         finished_called = [False]
 
-        async def finish():
-            for provider in self.storage_providers:
-                await provider.store_file(path, file_info)
-
-            finished_called[0] = True
-
         try:
             with open(fname, "wb") as f:
+
+                async def finish():
+                    # Ensure that all writes have been flushed and close the
+                    # file.
+                    f.flush()
+                    f.close()
+
+                    for provider in self.storage_providers:
+                        await provider.store_file(path, file_info)
+
+                    finished_called[0] = True
+
                 yield f, fname, finish
         except Exception:
             try:
@@ -210,7 +220,7 @@ class MediaStorage:
             if res:
                 with res:
                     consumer = BackgroundFileConsumer(
-                        open(local_path, "wb"), self.hs.get_reactor()
+                        open(local_path, "wb"), self.reactor
                     )
                     await res.write_to_consumer(consumer)
                     await consumer.wait()
diff --git a/synapse/server.py b/synapse/server.py
index 5e3752c333..b017e3489f 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -27,7 +27,8 @@ import logging
 import os
 from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, TypeVar, cast
 
-import twisted
+import twisted.internet.base
+import twisted.internet.tcp
 from twisted.mail.smtp import sendmail
 from twisted.web.iweb import IPolicyForHTTPS
 
@@ -54,25 +55,28 @@ from synapse.federation.sender import FederationSender
 from synapse.federation.transport.client import TransportLayerClient
 from synapse.groups.attestations import GroupAttestationSigning, GroupAttestionRenewer
 from synapse.groups.groups_server import GroupsServerHandler, GroupsServerWorkerHandler
-from synapse.handlers import Handlers
 from synapse.handlers.account_validity import AccountValidityHandler
 from synapse.handlers.acme import AcmeHandler
+from synapse.handlers.admin import AdminHandler
 from synapse.handlers.appservice import ApplicationServicesHandler
 from synapse.handlers.auth import AuthHandler, MacaroonGenerator
 from synapse.handlers.cas_handler import CasHandler
 from synapse.handlers.deactivate_account import DeactivateAccountHandler
 from synapse.handlers.device import DeviceHandler, DeviceWorkerHandler
 from synapse.handlers.devicemessage import DeviceMessageHandler
+from synapse.handlers.directory import DirectoryHandler
 from synapse.handlers.e2e_keys import E2eKeysHandler
 from synapse.handlers.e2e_room_keys import E2eRoomKeysHandler
 from synapse.handlers.events import EventHandler, EventStreamHandler
+from synapse.handlers.federation import FederationHandler
 from synapse.handlers.groups_local import GroupsLocalHandler, GroupsLocalWorkerHandler
+from synapse.handlers.identity import IdentityHandler
 from synapse.handlers.initial_sync import InitialSyncHandler
 from synapse.handlers.message import EventCreationHandler, MessageHandler
 from synapse.handlers.pagination import PaginationHandler
 from synapse.handlers.password_policy import PasswordPolicyHandler
 from synapse.handlers.presence import PresenceHandler
-from synapse.handlers.profile import BaseProfileHandler, MasterProfileHandler
+from synapse.handlers.profile import ProfileHandler
 from synapse.handlers.read_marker import ReadMarkerHandler
 from synapse.handlers.receipts import ReceiptsHandler
 from synapse.handlers.register import RegistrationHandler
@@ -84,13 +88,16 @@ from synapse.handlers.room import (
 from synapse.handlers.room_list import RoomListHandler
 from synapse.handlers.room_member import RoomMemberMasterHandler
 from synapse.handlers.room_member_worker import RoomMemberWorkerHandler
+from synapse.handlers.search import SearchHandler
 from synapse.handlers.set_password import SetPasswordHandler
+from synapse.handlers.sso import SsoHandler
 from synapse.handlers.stats import StatsHandler
 from synapse.handlers.sync import SyncHandler
 from synapse.handlers.typing import FollowerTypingHandler, TypingWriterHandler
 from synapse.handlers.user_directory import UserDirectoryHandler
 from synapse.http.client import InsecureInterceptableContextFactory, SimpleHttpClient
 from synapse.http.matrixfederationclient import MatrixFederationHttpClient
+from synapse.module_api import ModuleApi
 from synapse.notifier import Notifier
 from synapse.push.action_generator import ActionGenerator
 from synapse.push.pusherpool import PusherPool
@@ -140,7 +147,8 @@ def cache_in_self(builder: T) -> T:
             "@cache_in_self can only be used on functions starting with `get_`"
         )
 
-    depname = builder.__name__[len("get_") :]
+    # get_attr -> _attr
+    depname = builder.__name__[len("get") :]
 
     building = [False]
 
@@ -185,14 +193,28 @@ class HomeServer(metaclass=abc.ABCMeta):
             we are listening on to provide HTTP services.
     """
 
-    REQUIRED_ON_MASTER_STARTUP = ["user_directory_handler", "stats_handler"]
+    REQUIRED_ON_BACKGROUND_TASK_STARTUP = [
+        "account_validity",
+        "auth",
+        "deactivate_account",
+        "message",
+        "pagination",
+        "profile",
+        "stats",
+    ]
 
     # This is overridden in derived application classes
     # (such as synapse.app.homeserver.SynapseHomeServer) and gives the class to be
     # instantiated during setup() for future return by get_datastore()
     DATASTORE_CLASS = abc.abstractproperty()
 
-    def __init__(self, hostname: str, config: HomeServerConfig, reactor=None, **kwargs):
+    def __init__(
+        self,
+        hostname: str,
+        config: HomeServerConfig,
+        reactor=None,
+        version_string="Synapse",
+    ):
         """
         Args:
             hostname : The hostname for the server.
@@ -214,21 +236,10 @@ class HomeServer(metaclass=abc.ABCMeta):
         self._instance_id = random_string(5)
         self._instance_name = config.worker_name or "master"
 
-        self.clock = Clock(reactor)
-        self.distributor = Distributor()
-
-        self.registration_ratelimiter = Ratelimiter(
-            clock=self.clock,
-            rate_hz=config.rc_registration.per_second,
-            burst_count=config.rc_registration.burst_count,
-        )
+        self.version_string = version_string
 
         self.datastores = None  # type: Optional[Databases]
 
-        # Other kwargs are explicit dependencies
-        for depname in kwargs:
-            setattr(self, depname, kwargs[depname])
-
     def get_instance_id(self) -> str:
         """A unique ID for this synapse process instance.
 
@@ -251,14 +262,20 @@ class HomeServer(metaclass=abc.ABCMeta):
         self.datastores = Databases(self.DATASTORE_CLASS, self)
         logger.info("Finished setting up.")
 
-    def setup_master(self) -> None:
+        # Register background tasks required by this server. This must be done
+        # somewhat manually due to the background tasks not being registered
+        # unless handlers are instantiated.
+        if self.config.run_background_tasks:
+            self.setup_background_tasks()
+
+    def setup_background_tasks(self) -> None:
         """
         Some handlers have side effects on instantiation (like registering
         background updates). This function causes them to be fetched, and
         therefore instantiated, to run those side effects.
         """
-        for i in self.REQUIRED_ON_MASTER_STARTUP:
-            getattr(self, "get_" + i)()
+        for i in self.REQUIRED_ON_BACKGROUND_TASK_STARTUP:
+            getattr(self, "get_" + i + "_handler")()
 
     def get_reactor(self) -> twisted.internet.base.ReactorBase:
         """
@@ -276,8 +293,9 @@ class HomeServer(metaclass=abc.ABCMeta):
     def is_mine_id(self, string: str) -> bool:
         return string.split(":", 1)[1] == self.hostname
 
+    @cache_in_self
     def get_clock(self) -> Clock:
-        return self.clock
+        return Clock(self._reactor)
 
     def get_datastore(self) -> DataStore:
         if not self.datastores:
@@ -294,11 +312,17 @@ class HomeServer(metaclass=abc.ABCMeta):
     def get_config(self) -> HomeServerConfig:
         return self.config
 
+    @cache_in_self
     def get_distributor(self) -> Distributor:
-        return self.distributor
+        return Distributor()
 
+    @cache_in_self
     def get_registration_ratelimiter(self) -> Ratelimiter:
-        return self.registration_ratelimiter
+        return Ratelimiter(
+            clock=self.get_clock(),
+            rate_hz=self.config.rc_registration.per_second,
+            burst_count=self.config.rc_registration.burst_count,
+        )
 
     @cache_in_self
     def get_federation_client(self) -> FederationClient:
@@ -308,10 +332,6 @@ class HomeServer(metaclass=abc.ABCMeta):
     def get_federation_server(self) -> FederationServer:
         return FederationServer(self)
 
-    @cache_in_self
-    def get_handlers(self) -> Handlers:
-        return Handlers(self)
-
     @cache_in_self
     def get_notifier(self) -> Notifier:
         return Notifier(self)
@@ -371,6 +391,10 @@ class HomeServer(metaclass=abc.ABCMeta):
         else:
             return FollowerTypingHandler(self)
 
+    @cache_in_self
+    def get_sso_handler(self) -> SsoHandler:
+        return SsoHandler(self)
+
     @cache_in_self
     def get_sync_handler(self) -> SyncHandler:
         return SyncHandler(self)
@@ -398,6 +422,10 @@ class HomeServer(metaclass=abc.ABCMeta):
     def get_device_message_handler(self) -> DeviceMessageHandler:
         return DeviceMessageHandler(self)
 
+    @cache_in_self
+    def get_directory_handler(self) -> DirectoryHandler:
+        return DirectoryHandler(self)
+
     @cache_in_self
     def get_e2e_keys_handler(self) -> E2eKeysHandler:
         return E2eKeysHandler(self)
@@ -410,6 +438,10 @@ class HomeServer(metaclass=abc.ABCMeta):
     def get_acme_handler(self) -> AcmeHandler:
         return AcmeHandler(self)
 
+    @cache_in_self
+    def get_admin_handler(self) -> AdminHandler:
+        return AdminHandler(self)
+
     @cache_in_self
     def get_application_service_api(self) -> ApplicationServiceApi:
         return ApplicationServiceApi(self)
@@ -430,16 +462,21 @@ class HomeServer(metaclass=abc.ABCMeta):
     def get_event_stream_handler(self) -> EventStreamHandler:
         return EventStreamHandler(self)
 
+    @cache_in_self
+    def get_federation_handler(self) -> FederationHandler:
+        return FederationHandler(self)
+
+    @cache_in_self
+    def get_identity_handler(self) -> IdentityHandler:
+        return IdentityHandler(self)
+
     @cache_in_self
     def get_initial_sync_handler(self) -> InitialSyncHandler:
         return InitialSyncHandler(self)
 
     @cache_in_self
     def get_profile_handler(self):
-        if self.config.worker_app:
-            return BaseProfileHandler(self)
-        else:
-            return MasterProfileHandler(self)
+        return ProfileHandler(self)
 
     @cache_in_self
     def get_event_creation_handler(self) -> EventCreationHandler:
@@ -449,6 +486,10 @@ class HomeServer(metaclass=abc.ABCMeta):
     def get_deactivate_account_handler(self) -> DeactivateAccountHandler:
         return DeactivateAccountHandler(self)
 
+    @cache_in_self
+    def get_search_handler(self) -> SearchHandler:
+        return SearchHandler(self)
+
     @cache_in_self
     def get_set_password_handler(self) -> SetPasswordHandler:
         return SetPasswordHandler(self)
@@ -645,7 +686,11 @@ class HomeServer(metaclass=abc.ABCMeta):
 
     @cache_in_self
     def get_federation_ratelimiter(self) -> FederationRateLimiter:
-        return FederationRateLimiter(self.clock, config=self.config.rc_federation)
+        return FederationRateLimiter(self.get_clock(), config=self.config.rc_federation)
+
+    @cache_in_self
+    def get_module_api(self) -> ModuleApi:
+        return ModuleApi(self, self.get_auth_handler())
 
     async def remove_pusher(self, app_id: str, push_key: str, user_id: str):
         return await self.get_pusherpool().remove_pusher(app_id, push_key, user_id)
diff --git a/synapse/server_notices/consent_server_notices.py b/synapse/server_notices/consent_server_notices.py
index 3673e7f47e..9137c4edb1 100644
--- a/synapse/server_notices/consent_server_notices.py
+++ b/synapse/server_notices/consent_server_notices.py
@@ -104,7 +104,7 @@ class ConsentServerNotices:
 
 
 def copy_with_str_subst(x: Any, substitutions: Any) -> Any:
-    """Deep-copy a structure, carrying out string substitions on any strings
+    """Deep-copy a structure, carrying out string substitutions on any strings
 
     Args:
         x (object): structure to be copied
diff --git a/synapse/server_notices/server_notices_manager.py b/synapse/server_notices/server_notices_manager.py
index 0422d4c7ce..100dbd5e2c 100644
--- a/synapse/server_notices/server_notices_manager.py
+++ b/synapse/server_notices/server_notices_manager.py
@@ -39,6 +39,7 @@ class ServerNoticesManager:
         self._room_member_handler = hs.get_room_member_handler()
         self._event_creation_handler = hs.get_event_creation_handler()
         self._is_mine_id = hs.is_mine_id
+        self._server_name = hs.hostname
 
         self._notifier = hs.get_notifier()
         self.server_notices_mxid = self._config.server_notices_mxid
@@ -72,7 +73,9 @@ class ServerNoticesManager:
         await self.maybe_invite_user_to_room(user_id, room_id)
 
         system_mxid = self._config.server_notices_mxid
-        requester = create_requester(system_mxid)
+        requester = create_requester(
+            system_mxid, authenticated_entity=self._server_name
+        )
 
         logger.info("Sending server notice to %s", user_id)
 
@@ -119,7 +122,7 @@ class ServerNoticesManager:
             # manages to invite the system user to a room, that doesn't make it
             # the server notices room.
             user_ids = await self._store.get_users_in_room(room.room_id)
-            if self.server_notices_mxid in user_ids:
+            if len(user_ids) <= 2 and self.server_notices_mxid in user_ids:
                 # we found a room which our user shares with the system notice
                 # user
                 logger.info(
@@ -145,7 +148,9 @@ class ServerNoticesManager:
                 "avatar_url": self._config.server_notices_mxid_avatar_url,
             }
 
-        requester = create_requester(self.server_notices_mxid)
+        requester = create_requester(
+            self.server_notices_mxid, authenticated_entity=self._server_name
+        )
         info, _ = await self._room_creation_handler.create_room(
             requester,
             config={
@@ -174,7 +179,9 @@ class ServerNoticesManager:
             user_id: The ID of the user to invite.
             room_id: The ID of the room to invite the user to.
         """
-        requester = create_requester(self.server_notices_mxid)
+        requester = create_requester(
+            self.server_notices_mxid, authenticated_entity=self._server_name
+        )
 
         # Check whether the user has already joined or been invited to this room. If
         # that's the case, there is no need to re-invite them.
diff --git a/synapse/spam_checker_api/__init__.py b/synapse/spam_checker_api/__init__.py
index 395ac5ab02..3ce25bb012 100644
--- a/synapse/spam_checker_api/__init__.py
+++ b/synapse/spam_checker_api/__init__.py
@@ -12,19 +12,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import logging
 from enum import Enum
 
-from twisted.internet import defer
-
-from synapse.storage.state import StateFilter
-
-MYPY = False
-if MYPY:
-    import synapse.server
-
-logger = logging.getLogger(__name__)
-
 
 class RegistrationBehaviour(Enum):
     """
@@ -34,35 +23,3 @@ class RegistrationBehaviour(Enum):
     ALLOW = "allow"
     SHADOW_BAN = "shadow_ban"
     DENY = "deny"
-
-
-class SpamCheckerApi:
-    """A proxy object that gets passed to spam checkers so they can get
-    access to rooms and other relevant information.
-    """
-
-    def __init__(self, hs: "synapse.server.HomeServer"):
-        self.hs = hs
-
-        self._store = hs.get_datastore()
-
-    @defer.inlineCallbacks
-    def get_state_events_in_room(self, room_id: str, types: tuple) -> defer.Deferred:
-        """Gets state events for the given room.
-
-        Args:
-            room_id: The room ID to get state events in.
-            types: The event type and state key (using None
-                to represent 'any') of the room state to acquire.
-
-        Returns:
-            twisted.internet.defer.Deferred[list(synapse.events.FrozenEvent)]:
-                The filtered state events in the room.
-        """
-        state_ids = yield defer.ensureDeferred(
-            self._store.get_filtered_current_state_ids(
-                room_id=room_id, state_filter=StateFilter.from_types(types)
-            )
-        )
-        state = yield defer.ensureDeferred(self._store.get_events(state_ids.values()))
-        return state.values()
diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index 31082bb16a..1fa3b280b4 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -547,7 +547,7 @@ class StateResolutionHandler:
             event_map:
                 a dict from event_id to event, for any events that we happen to
                 have in flight (eg, those currently being persisted). This will be
-                used as a starting point fof finding the state we need; any missing
+                used as a starting point for finding the state we need; any missing
                 events will be requested via state_res_store.
 
                 If None, all events will be fetched via state_res_store.
@@ -738,7 +738,7 @@ def _make_state_cache_entry(
 
     # failing that, look for the closest match.
     prev_group = None
-    delta_ids = None
+    delta_ids = None  # type: Optional[StateMap[str]]
 
     for old_group, old_state in state_groups_ids.items():
         n_delta_ids = {k: v for k, v in new_state.items() if old_state.get(k) != v}
diff --git a/synapse/state/v1.py b/synapse/state/v1.py
index a493279cbd..85edae053d 100644
--- a/synapse/state/v1.py
+++ b/synapse/state/v1.py
@@ -56,7 +56,7 @@ async def resolve_events_with_store(
         event_map:
             a dict from event_id to event, for any events that we happen to
             have in flight (eg, those currently being persisted). This will be
-            used as a starting point fof finding the state we need; any missing
+            used as a starting point for finding the state we need; any missing
             events will be requested via state_map_factory.
 
             If None, all events will be fetched via state_map_factory.
diff --git a/synapse/state/v2.py b/synapse/state/v2.py
index edf94e7ad6..f57df0d728 100644
--- a/synapse/state/v2.py
+++ b/synapse/state/v2.py
@@ -69,7 +69,7 @@ async def resolve_events_with_store(
         event_map:
             a dict from event_id to event, for any events that we happen to
             have in flight (eg, those currently being persisted). This will be
-            used as a starting point fof finding the state we need; any missing
+            used as a starting point for finding the state we need; any missing
             events will be requested via state_res_store.
 
             If None, all events will be fetched via state_res_store.
diff --git a/synapse/static/client/login/js/login.js b/synapse/static/client/login/js/login.js
index 3678670ec7..744800ec77 100644
--- a/synapse/static/client/login/js/login.js
+++ b/synapse/static/client/login/js/login.js
@@ -182,7 +182,7 @@ matrixLogin.passwordLogin = function() {
 };
 
 /*
- * The onLogin function gets called after a succesful login.
+ * The onLogin function gets called after a successful login.
  *
  * It is expected that implementations override this to be notified when the
  * login is complete. The response to the login call is provided as the single
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index ab49d227de..2b196ded1b 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -76,14 +76,16 @@ class SQLBaseStore(metaclass=ABCMeta):
         """
 
         try:
-            if key is None:
-                getattr(self, cache_name).invalidate_all()
-            else:
-                getattr(self, cache_name).invalidate(tuple(key))
+            cache = getattr(self, cache_name)
         except AttributeError:
             # We probably haven't pulled in the cache in this worker,
             # which is fine.
-            pass
+            return
+
+        if key is None:
+            cache.invalidate_all()
+        else:
+            cache.invalidate(tuple(key))
 
 
 def db_to_json(db_content):
diff --git a/synapse/storage/database.py b/synapse/storage/database.py
index 6116191b16..d1b5760c2c 100644
--- a/synapse/storage/database.py
+++ b/synapse/storage/database.py
@@ -32,6 +32,7 @@ from typing import (
     overload,
 )
 
+import attr
 from prometheus_client import Histogram
 from typing_extensions import Literal
 
@@ -87,16 +88,25 @@ def make_pool(
     """Get the connection pool for the database.
     """
 
+    # By default enable `cp_reconnect`. We need to fiddle with db_args in case
+    # someone has explicitly set `cp_reconnect`.
+    db_args = dict(db_config.config.get("args", {}))
+    db_args.setdefault("cp_reconnect", True)
+
     return adbapi.ConnectionPool(
         db_config.config["name"],
         cp_reactor=reactor,
-        cp_openfun=engine.on_new_connection,
-        **db_config.config.get("args", {})
+        cp_openfun=lambda conn: engine.on_new_connection(
+            LoggingDatabaseConnection(conn, engine, "on_new_connection")
+        ),
+        **db_args,
     )
 
 
 def make_conn(
-    db_config: DatabaseConnectionConfig, engine: BaseDatabaseEngine
+    db_config: DatabaseConnectionConfig,
+    engine: BaseDatabaseEngine,
+    default_txn_name: str,
 ) -> Connection:
     """Make a new connection to the database and return it.
 
@@ -109,11 +119,60 @@ def make_conn(
         for k, v in db_config.config.get("args", {}).items()
         if not k.startswith("cp_")
     }
-    db_conn = engine.module.connect(**db_params)
+    native_db_conn = engine.module.connect(**db_params)
+    db_conn = LoggingDatabaseConnection(native_db_conn, engine, default_txn_name)
+
     engine.on_new_connection(db_conn)
     return db_conn
 
 
+@attr.s(slots=True)
+class LoggingDatabaseConnection:
+    """A wrapper around a database connection that returns `LoggingTransaction`
+    as its cursor class.
+
+    This is mainly used on startup to ensure that queries get logged correctly
+    """
+
+    conn = attr.ib(type=Connection)
+    engine = attr.ib(type=BaseDatabaseEngine)
+    default_txn_name = attr.ib(type=str)
+
+    def cursor(
+        self, *, txn_name=None, after_callbacks=None, exception_callbacks=None
+    ) -> "LoggingTransaction":
+        if not txn_name:
+            txn_name = self.default_txn_name
+
+        return LoggingTransaction(
+            self.conn.cursor(),
+            name=txn_name,
+            database_engine=self.engine,
+            after_callbacks=after_callbacks,
+            exception_callbacks=exception_callbacks,
+        )
+
+    def close(self) -> None:
+        self.conn.close()
+
+    def commit(self) -> None:
+        self.conn.commit()
+
+    def rollback(self, *args, **kwargs) -> None:
+        self.conn.rollback(*args, **kwargs)
+
+    def __enter__(self) -> "Connection":
+        self.conn.__enter__()
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback) -> Optional[bool]:
+        return self.conn.__exit__(exc_type, exc_value, traceback)
+
+    # Proxy through any unknown lookups to the DB conn class.
+    def __getattr__(self, name):
+        return getattr(self.conn, name)
+
+
 # The type of entry which goes on our after_callbacks and exception_callbacks lists.
 #
 # Python 3.5.2 doesn't support Callable with an ellipsis, so we wrap it in quotes so
@@ -247,6 +306,12 @@ class LoggingTransaction:
     def close(self) -> None:
         self.txn.close()
 
+    def __enter__(self) -> "LoggingTransaction":
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.close()
+
 
 class PerformanceCounters:
     def __init__(self):
@@ -395,7 +460,7 @@ class DatabasePool:
 
     def new_transaction(
         self,
-        conn: Connection,
+        conn: LoggingDatabaseConnection,
         desc: str,
         after_callbacks: List[_CallbackListEntry],
         exception_callbacks: List[_CallbackListEntry],
@@ -436,12 +501,10 @@ class DatabasePool:
             i = 0
             N = 5
             while True:
-                cursor = LoggingTransaction(
-                    conn.cursor(),
-                    name,
-                    self.engine,
-                    after_callbacks,
-                    exception_callbacks,
+                cursor = conn.cursor(
+                    txn_name=name,
+                    after_callbacks=after_callbacks,
+                    exception_callbacks=exception_callbacks,
                 )
                 try:
                     r = func(cursor, *args, **kwargs)
@@ -574,7 +637,7 @@ class DatabasePool:
                 func,
                 *args,
                 db_autocommit=db_autocommit,
-                **kwargs
+                **kwargs,
             )
 
             for after_callback, after_args, after_kwargs in after_callbacks:
@@ -638,7 +701,10 @@ class DatabasePool:
                     if db_autocommit:
                         self.engine.attempt_to_set_autocommit(conn, True)
 
-                    return func(conn, *args, **kwargs)
+                    db_conn = LoggingDatabaseConnection(
+                        conn, self.engine, "runWithConnection"
+                    )
+                    return func(db_conn, *args, **kwargs)
                 finally:
                     if db_autocommit:
                         self.engine.attempt_to_set_autocommit(conn, False)
@@ -832,6 +898,12 @@ class DatabasePool:
         attempts = 0
         while True:
             try:
+                # We can autocommit if we are going to use native upserts
+                autocommit = (
+                    self.engine.can_native_upsert
+                    and table not in self._unsafe_to_upsert_tables
+                )
+
                 return await self.runInteraction(
                     desc,
                     self.simple_upsert_txn,
@@ -840,6 +912,7 @@ class DatabasePool:
                     values,
                     insertion_values,
                     lock=lock,
+                    db_autocommit=autocommit,
                 )
             except self.engine.module.IntegrityError as e:
                 attempts += 1
@@ -1002,6 +1075,43 @@ class DatabasePool:
         )
         txn.execute(sql, list(allvalues.values()))
 
+    async def simple_upsert_many(
+        self,
+        table: str,
+        key_names: Collection[str],
+        key_values: Collection[Iterable[Any]],
+        value_names: Collection[str],
+        value_values: Iterable[Iterable[Any]],
+        desc: str,
+    ) -> None:
+        """
+        Upsert, many times.
+
+        Args:
+            table: The table to upsert into
+            key_names: The key column names.
+            key_values: A list of each row's key column values.
+            value_names: The value column names
+            value_values: A list of each row's value column values.
+                Ignored if value_names is empty.
+        """
+
+        # We can autocommit if we are going to use native upserts
+        autocommit = (
+            self.engine.can_native_upsert and table not in self._unsafe_to_upsert_tables
+        )
+
+        return await self.runInteraction(
+            desc,
+            self.simple_upsert_many_txn,
+            table,
+            key_names,
+            key_values,
+            value_names,
+            value_values,
+            db_autocommit=autocommit,
+        )
+
     def simple_upsert_many_txn(
         self,
         txn: LoggingTransaction,
@@ -1153,7 +1263,13 @@ class DatabasePool:
             desc: description of the transaction, for logging and metrics
         """
         return await self.runInteraction(
-            desc, self.simple_select_one_txn, table, keyvalues, retcols, allow_none
+            desc,
+            self.simple_select_one_txn,
+            table,
+            keyvalues,
+            retcols,
+            allow_none,
+            db_autocommit=True,
         )
 
     @overload
@@ -1204,6 +1320,7 @@ class DatabasePool:
             keyvalues,
             retcol,
             allow_none=allow_none,
+            db_autocommit=True,
         )
 
     @overload
@@ -1285,7 +1402,12 @@ class DatabasePool:
             Results in a list
         """
         return await self.runInteraction(
-            desc, self.simple_select_onecol_txn, table, keyvalues, retcol
+            desc,
+            self.simple_select_onecol_txn,
+            table,
+            keyvalues,
+            retcol,
+            db_autocommit=True,
         )
 
     async def simple_select_list(
@@ -1310,7 +1432,12 @@ class DatabasePool:
             A list of dictionaries.
         """
         return await self.runInteraction(
-            desc, self.simple_select_list_txn, table, keyvalues, retcols
+            desc,
+            self.simple_select_list_txn,
+            table,
+            keyvalues,
+            retcols,
+            db_autocommit=True,
         )
 
     @classmethod
@@ -1389,6 +1516,7 @@ class DatabasePool:
                 chunk,
                 keyvalues,
                 retcols,
+                db_autocommit=True,
             )
 
             results.extend(rows)
@@ -1487,7 +1615,12 @@ class DatabasePool:
             desc: description of the transaction, for logging and metrics
         """
         await self.runInteraction(
-            desc, self.simple_update_one_txn, table, keyvalues, updatevalues
+            desc,
+            self.simple_update_one_txn,
+            table,
+            keyvalues,
+            updatevalues,
+            db_autocommit=True,
         )
 
     @classmethod
@@ -1546,7 +1679,9 @@ class DatabasePool:
             keyvalues: dict of column names and values to select the row with
             desc: description of the transaction, for logging and metrics
         """
-        await self.runInteraction(desc, self.simple_delete_one_txn, table, keyvalues)
+        await self.runInteraction(
+            desc, self.simple_delete_one_txn, table, keyvalues, db_autocommit=True,
+        )
 
     @staticmethod
     def simple_delete_one_txn(
@@ -1585,7 +1720,9 @@ class DatabasePool:
         Returns:
             The number of deleted rows.
         """
-        return await self.runInteraction(desc, self.simple_delete_txn, table, keyvalues)
+        return await self.runInteraction(
+            desc, self.simple_delete_txn, table, keyvalues, db_autocommit=True
+        )
 
     @staticmethod
     def simple_delete_txn(
@@ -1633,7 +1770,13 @@ class DatabasePool:
             Number rows deleted
         """
         return await self.runInteraction(
-            desc, self.simple_delete_many_txn, table, column, iterable, keyvalues
+            desc,
+            self.simple_delete_many_txn,
+            table,
+            column,
+            iterable,
+            keyvalues,
+            db_autocommit=True,
         )
 
     @staticmethod
@@ -1678,7 +1821,7 @@ class DatabasePool:
 
     def get_cache_dict(
         self,
-        db_conn: Connection,
+        db_conn: LoggingDatabaseConnection,
         table: str,
         entity_column: str,
         stream_column: str,
@@ -1699,9 +1842,7 @@ class DatabasePool:
             "limit": limit,
         }
 
-        sql = self.engine.convert_param_style(sql)
-
-        txn = db_conn.cursor()
+        txn = db_conn.cursor(txn_name="get_cache_dict")
         txn.execute(sql, (int(max_value),))
 
         cache = {row[0]: int(row[1]) for row in txn}
@@ -1801,7 +1942,13 @@ class DatabasePool:
         """
 
         return await self.runInteraction(
-            desc, self.simple_search_list_txn, table, term, col, retcols
+            desc,
+            self.simple_search_list_txn,
+            table,
+            term,
+            col,
+            retcols,
+            db_autocommit=True,
         )
 
     @classmethod
diff --git a/synapse/storage/databases/__init__.py b/synapse/storage/databases/__init__.py
index aa5d490624..0c24325011 100644
--- a/synapse/storage/databases/__init__.py
+++ b/synapse/storage/databases/__init__.py
@@ -46,7 +46,7 @@ class Databases:
             db_name = database_config.name
             engine = create_engine(database_config.config)
 
-            with make_conn(database_config, engine) as db_conn:
+            with make_conn(database_config, engine, "startup") as db_conn:
                 logger.info("[database config %r]: Checking database server", db_name)
                 engine.check_database(db_conn)
 
diff --git a/synapse/storage/databases/main/__init__.py b/synapse/storage/databases/main/__init__.py
index 0cb12f4c61..43660ec4fb 100644
--- a/synapse/storage/databases/main/__init__.py
+++ b/synapse/storage/databases/main/__init__.py
@@ -15,9 +15,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import calendar
 import logging
-import time
 from typing import Any, Dict, List, Optional, Tuple
 
 from synapse.api.constants import PresenceState
@@ -148,7 +146,6 @@ class DataStore(
             db_conn, "e2e_cross_signing_keys", "stream_id"
         )
 
-        self._access_tokens_id_gen = IdGenerator(db_conn, "access_tokens", "id")
         self._event_reports_id_gen = IdGenerator(db_conn, "event_reports", "id")
         self._push_rule_id_gen = IdGenerator(db_conn, "push_rules", "id")
         self._push_rules_enable_id_gen = IdGenerator(db_conn, "push_rules_enable", "id")
@@ -268,9 +265,6 @@ class DataStore(
         self._stream_order_on_start = self.get_room_max_stream_ordering()
         self._min_stream_order_on_start = self.get_room_min_stream_ordering()
 
-        # Used in _generate_user_daily_visits to keep track of progress
-        self._last_user_visit_update = self._get_start_of_day()
-
     def get_device_stream_token(self) -> int:
         return self._device_list_id_gen.get_current_token()
 
@@ -289,7 +283,6 @@ class DataStore(
             " last_user_sync_ts, status_msg, currently_active FROM presence_stream"
             " WHERE state != ?"
         )
-        sql = self.database_engine.convert_param_style(sql)
 
         txn = db_conn.cursor()
         txn.execute(sql, (PresenceState.OFFLINE,))
@@ -301,192 +294,6 @@ class DataStore(
 
         return [UserPresenceState(**row) for row in rows]
 
-    async def count_daily_users(self) -> int:
-        """
-        Counts the number of users who used this homeserver in the last 24 hours.
-        """
-        yesterday = int(self._clock.time_msec()) - (1000 * 60 * 60 * 24)
-        return await self.db_pool.runInteraction(
-            "count_daily_users", self._count_users, yesterday
-        )
-
-    async def count_monthly_users(self) -> int:
-        """
-        Counts the number of users who used this homeserver in the last 30 days.
-        Note this method is intended for phonehome metrics only and is different
-        from the mau figure in synapse.storage.monthly_active_users which,
-        amongst other things, includes a 3 day grace period before a user counts.
-        """
-        thirty_days_ago = int(self._clock.time_msec()) - (1000 * 60 * 60 * 24 * 30)
-        return await self.db_pool.runInteraction(
-            "count_monthly_users", self._count_users, thirty_days_ago
-        )
-
-    def _count_users(self, txn, time_from):
-        """
-        Returns number of users seen in the past time_from period
-        """
-        sql = """
-            SELECT COALESCE(count(*), 0) FROM (
-                SELECT user_id FROM user_ips
-                WHERE last_seen > ?
-                GROUP BY user_id
-            ) u
-        """
-        txn.execute(sql, (time_from,))
-        (count,) = txn.fetchone()
-        return count
-
-    async def count_r30_users(self) -> Dict[str, int]:
-        """
-        Counts the number of 30 day retained users, defined as:-
-         * Users who have created their accounts more than 30 days ago
-         * Where last seen at most 30 days ago
-         * Where account creation and last_seen are > 30 days apart
-
-        Returns:
-             A mapping of counts globally as well as broken out by platform.
-        """
-
-        def _count_r30_users(txn):
-            thirty_days_in_secs = 86400 * 30
-            now = int(self._clock.time())
-            thirty_days_ago_in_secs = now - thirty_days_in_secs
-
-            sql = """
-                SELECT platform, COALESCE(count(*), 0) FROM (
-                     SELECT
-                        users.name, platform, users.creation_ts * 1000,
-                        MAX(uip.last_seen)
-                     FROM users
-                     INNER JOIN (
-                         SELECT
-                         user_id,
-                         last_seen,
-                         CASE
-                             WHEN user_agent LIKE '%%Android%%' THEN 'android'
-                             WHEN user_agent LIKE '%%iOS%%' THEN 'ios'
-                             WHEN user_agent LIKE '%%Electron%%' THEN 'electron'
-                             WHEN user_agent LIKE '%%Mozilla%%' THEN 'web'
-                             WHEN user_agent LIKE '%%Gecko%%' THEN 'web'
-                             ELSE 'unknown'
-                         END
-                         AS platform
-                         FROM user_ips
-                     ) uip
-                     ON users.name = uip.user_id
-                     AND users.appservice_id is NULL
-                     AND users.creation_ts < ?
-                     AND uip.last_seen/1000 > ?
-                     AND (uip.last_seen/1000) - users.creation_ts > 86400 * 30
-                     GROUP BY users.name, platform, users.creation_ts
-                ) u GROUP BY platform
-            """
-
-            results = {}
-            txn.execute(sql, (thirty_days_ago_in_secs, thirty_days_ago_in_secs))
-
-            for row in txn:
-                if row[0] == "unknown":
-                    pass
-                results[row[0]] = row[1]
-
-            sql = """
-                SELECT COALESCE(count(*), 0) FROM (
-                    SELECT users.name, users.creation_ts * 1000,
-                                                        MAX(uip.last_seen)
-                    FROM users
-                    INNER JOIN (
-                        SELECT
-                        user_id,
-                        last_seen
-                        FROM user_ips
-                    ) uip
-                    ON users.name = uip.user_id
-                    AND appservice_id is NULL
-                    AND users.creation_ts < ?
-                    AND uip.last_seen/1000 > ?
-                    AND (uip.last_seen/1000) - users.creation_ts > 86400 * 30
-                    GROUP BY users.name, users.creation_ts
-                ) u
-            """
-
-            txn.execute(sql, (thirty_days_ago_in_secs, thirty_days_ago_in_secs))
-
-            (count,) = txn.fetchone()
-            results["all"] = count
-
-            return results
-
-        return await self.db_pool.runInteraction("count_r30_users", _count_r30_users)
-
-    def _get_start_of_day(self):
-        """
-        Returns millisecond unixtime for start of UTC day.
-        """
-        now = time.gmtime()
-        today_start = calendar.timegm((now.tm_year, now.tm_mon, now.tm_mday, 0, 0, 0))
-        return today_start * 1000
-
-    async def generate_user_daily_visits(self) -> None:
-        """
-        Generates daily visit data for use in cohort/ retention analysis
-        """
-
-        def _generate_user_daily_visits(txn):
-            logger.info("Calling _generate_user_daily_visits")
-            today_start = self._get_start_of_day()
-            a_day_in_milliseconds = 24 * 60 * 60 * 1000
-            now = self.clock.time_msec()
-
-            sql = """
-                INSERT INTO user_daily_visits (user_id, device_id, timestamp)
-                    SELECT u.user_id, u.device_id, ?
-                    FROM user_ips AS u
-                    LEFT JOIN (
-                      SELECT user_id, device_id, timestamp FROM user_daily_visits
-                      WHERE timestamp = ?
-                    ) udv
-                    ON u.user_id = udv.user_id AND u.device_id=udv.device_id
-                    INNER JOIN users ON users.name=u.user_id
-                    WHERE last_seen > ? AND last_seen <= ?
-                    AND udv.timestamp IS NULL AND users.is_guest=0
-                    AND users.appservice_id IS NULL
-                    GROUP BY u.user_id, u.device_id
-            """
-
-            # This means that the day has rolled over but there could still
-            # be entries from the previous day. There is an edge case
-            # where if the user logs in at 23:59 and overwrites their
-            # last_seen at 00:01 then they will not be counted in the
-            # previous day's stats - it is important that the query is run
-            # often to minimise this case.
-            if today_start > self._last_user_visit_update:
-                yesterday_start = today_start - a_day_in_milliseconds
-                txn.execute(
-                    sql,
-                    (
-                        yesterday_start,
-                        yesterday_start,
-                        self._last_user_visit_update,
-                        today_start,
-                    ),
-                )
-                self._last_user_visit_update = today_start
-
-            txn.execute(
-                sql, (today_start, today_start, self._last_user_visit_update, now)
-            )
-            # Update _last_user_visit_update to now. The reason to do this
-            # rather just clamping to the beginning of the day is to limit
-            # the size of the join - meaning that the query can be run more
-            # frequently
-            self._last_user_visit_update = now
-
-        await self.db_pool.runInteraction(
-            "generate_user_daily_visits", _generate_user_daily_visits
-        )
-
     async def get_users(self) -> List[Dict[str, Any]]:
         """Function to retrieve a list of users in users table.
 
diff --git a/synapse/storage/databases/main/account_data.py b/synapse/storage/databases/main/account_data.py
index ef81d73573..49ee23470d 100644
--- a/synapse/storage/databases/main/account_data.py
+++ b/synapse/storage/databases/main/account_data.py
@@ -18,6 +18,7 @@ import abc
 import logging
 from typing import Dict, List, Optional, Tuple
 
+from synapse.api.constants import AccountDataTypes
 from synapse.storage._base import SQLBaseStore, db_to_json
 from synapse.storage.database import DatabasePool
 from synapse.storage.util.id_generators import StreamIdGenerator
@@ -291,14 +292,18 @@ class AccountDataWorkerStore(SQLBaseStore, metaclass=abc.ABCMeta):
         self, ignored_user_id: str, ignorer_user_id: str, cache_context: _CacheContext
     ) -> bool:
         ignored_account_data = await self.get_global_account_data_by_type_for_user(
-            "m.ignored_user_list",
+            AccountDataTypes.IGNORED_USER_LIST,
             ignorer_user_id,
             on_invalidate=cache_context.invalidate,
         )
         if not ignored_account_data:
             return False
 
-        return ignored_user_id in ignored_account_data.get("ignored_users", {})
+        try:
+            return ignored_user_id in ignored_account_data.get("ignored_users", {})
+        except TypeError:
+            # The type of the ignored_users field is invalid.
+            return False
 
 
 class AccountDataStore(AccountDataWorkerStore):
diff --git a/synapse/storage/databases/main/appservice.py b/synapse/storage/databases/main/appservice.py
index 85f6b1e3fd..e550cbc866 100644
--- a/synapse/storage/databases/main/appservice.py
+++ b/synapse/storage/databases/main/appservice.py
@@ -15,18 +15,31 @@
 # limitations under the License.
 import logging
 import re
+from typing import TYPE_CHECKING, List, Optional, Pattern, Tuple
 
-from synapse.appservice import AppServiceTransaction
+from synapse.appservice import (
+    ApplicationService,
+    ApplicationServiceState,
+    AppServiceTransaction,
+)
 from synapse.config.appservice import load_appservices
+from synapse.events import EventBase
 from synapse.storage._base import SQLBaseStore, db_to_json
 from synapse.storage.database import DatabasePool
 from synapse.storage.databases.main.events_worker import EventsWorkerStore
+from synapse.storage.types import Connection
+from synapse.types import JsonDict
 from synapse.util import json_encoder
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
-def _make_exclusive_regex(services_cache):
+def _make_exclusive_regex(
+    services_cache: List[ApplicationService],
+) -> Optional[Pattern]:
     # We precompile a regex constructed from all the regexes that the AS's
     # have registered for exclusive users.
     exclusive_user_regexes = [
@@ -36,17 +49,19 @@ def _make_exclusive_regex(services_cache):
     ]
     if exclusive_user_regexes:
         exclusive_user_regex = "|".join("(" + r + ")" for r in exclusive_user_regexes)
-        exclusive_user_regex = re.compile(exclusive_user_regex)
+        exclusive_user_pattern = re.compile(
+            exclusive_user_regex
+        )  # type: Optional[Pattern]
     else:
         # We handle this case specially otherwise the constructed regex
         # will always match
-        exclusive_user_regex = None
+        exclusive_user_pattern = None
 
-    return exclusive_user_regex
+    return exclusive_user_pattern
 
 
 class ApplicationServiceWorkerStore(SQLBaseStore):
-    def __init__(self, database: DatabasePool, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn: Connection, hs: "HomeServer"):
         self.services_cache = load_appservices(
             hs.hostname, hs.config.app_service_config_files
         )
@@ -57,7 +72,7 @@ class ApplicationServiceWorkerStore(SQLBaseStore):
     def get_app_services(self):
         return self.services_cache
 
-    def get_if_app_services_interested_in_user(self, user_id):
+    def get_if_app_services_interested_in_user(self, user_id: str) -> bool:
         """Check if the user is one associated with an app service (exclusively)
         """
         if self.exclusive_user_regex:
@@ -65,7 +80,7 @@ class ApplicationServiceWorkerStore(SQLBaseStore):
         else:
             return False
 
-    def get_app_service_by_user_id(self, user_id):
+    def get_app_service_by_user_id(self, user_id: str) -> Optional[ApplicationService]:
         """Retrieve an application service from their user ID.
 
         All application services have associated with them a particular user ID.
@@ -74,35 +89,35 @@ class ApplicationServiceWorkerStore(SQLBaseStore):
         a user ID to an application service.
 
         Args:
-            user_id(str): The user ID to see if it is an application service.
+            user_id: The user ID to see if it is an application service.
         Returns:
-            synapse.appservice.ApplicationService or None.
+            The application service or None.
         """
         for service in self.services_cache:
             if service.sender == user_id:
                 return service
         return None
 
-    def get_app_service_by_token(self, token):
+    def get_app_service_by_token(self, token: str) -> Optional[ApplicationService]:
         """Get the application service with the given appservice token.
 
         Args:
-            token (str): The application service token.
+            token: The application service token.
         Returns:
-            synapse.appservice.ApplicationService or None.
+            The application service or None.
         """
         for service in self.services_cache:
             if service.token == token:
                 return service
         return None
 
-    def get_app_service_by_id(self, as_id):
+    def get_app_service_by_id(self, as_id: str) -> Optional[ApplicationService]:
         """Get the application service with the given appservice ID.
 
         Args:
-            as_id (str): The application service ID.
+            as_id: The application service ID.
         Returns:
-            synapse.appservice.ApplicationService or None.
+            The application service or None.
         """
         for service in self.services_cache:
             if service.id == as_id:
@@ -121,11 +136,13 @@ class ApplicationServiceStore(ApplicationServiceWorkerStore):
 class ApplicationServiceTransactionWorkerStore(
     ApplicationServiceWorkerStore, EventsWorkerStore
 ):
-    async def get_appservices_by_state(self, state):
+    async def get_appservices_by_state(
+        self, state: ApplicationServiceState
+    ) -> List[ApplicationService]:
         """Get a list of application services based on their state.
 
         Args:
-            state(ApplicationServiceState): The state to filter on.
+            state: The state to filter on.
         Returns:
             A list of ApplicationServices, which may be empty.
         """
@@ -142,13 +159,15 @@ class ApplicationServiceTransactionWorkerStore(
                     services.append(service)
         return services
 
-    async def get_appservice_state(self, service):
+    async def get_appservice_state(
+        self, service: ApplicationService
+    ) -> Optional[ApplicationServiceState]:
         """Get the application service state.
 
         Args:
-            service(ApplicationService): The service whose state to set.
+            service: The service whose state to set.
         Returns:
-            An ApplicationServiceState.
+            An ApplicationServiceState or none.
         """
         result = await self.db_pool.simple_select_one(
             "application_services_state",
@@ -161,26 +180,36 @@ class ApplicationServiceTransactionWorkerStore(
             return result.get("state")
         return None
 
-    async def set_appservice_state(self, service, state) -> None:
+    async def set_appservice_state(
+        self, service: ApplicationService, state: ApplicationServiceState
+    ) -> None:
         """Set the application service state.
 
         Args:
-            service(ApplicationService): The service whose state to set.
-            state(ApplicationServiceState): The connectivity state to apply.
+            service: The service whose state to set.
+            state: The connectivity state to apply.
         """
         await self.db_pool.simple_upsert(
             "application_services_state", {"as_id": service.id}, {"state": state}
         )
 
-    async def create_appservice_txn(self, service, events):
+    async def create_appservice_txn(
+        self,
+        service: ApplicationService,
+        events: List[EventBase],
+        ephemeral: List[JsonDict],
+    ) -> AppServiceTransaction:
         """Atomically creates a new transaction for this application service
-        with the given list of events.
+        with the given list of events. Ephemeral events are NOT persisted to the
+        database and are not resent if a transaction is retried.
 
         Args:
-            service(ApplicationService): The service who the transaction is for.
-            events(list<Event>): A list of events to put in the transaction.
+            service: The service who the transaction is for.
+            events: A list of persistent events to put in the transaction.
+            ephemeral: A list of ephemeral events to put in the transaction.
+
         Returns:
-            AppServiceTransaction: A new transaction.
+            A new transaction.
         """
 
         def _create_appservice_txn(txn):
@@ -207,19 +236,22 @@ class ApplicationServiceTransactionWorkerStore(
                 "VALUES(?,?,?)",
                 (service.id, new_txn_id, event_ids),
             )
-            return AppServiceTransaction(service=service, id=new_txn_id, events=events)
+            return AppServiceTransaction(
+                service=service, id=new_txn_id, events=events, ephemeral=ephemeral
+            )
 
         return await self.db_pool.runInteraction(
             "create_appservice_txn", _create_appservice_txn
         )
 
-    async def complete_appservice_txn(self, txn_id, service) -> None:
+    async def complete_appservice_txn(
+        self, txn_id: int, service: ApplicationService
+    ) -> None:
         """Completes an application service transaction.
 
         Args:
-            txn_id(str): The transaction ID being completed.
-            service(ApplicationService): The application service which was sent
-            this transaction.
+            txn_id: The transaction ID being completed.
+            service: The application service which was sent this transaction.
         """
         txn_id = int(txn_id)
 
@@ -259,12 +291,13 @@ class ApplicationServiceTransactionWorkerStore(
             "complete_appservice_txn", _complete_appservice_txn
         )
 
-    async def get_oldest_unsent_txn(self, service):
-        """Get the oldest transaction which has not been sent for this
-        service.
+    async def get_oldest_unsent_txn(
+        self, service: ApplicationService
+    ) -> Optional[AppServiceTransaction]:
+        """Get the oldest transaction which has not been sent for this service.
 
         Args:
-            service(ApplicationService): The app service to get the oldest txn.
+            service: The app service to get the oldest txn.
         Returns:
             An AppServiceTransaction or None.
         """
@@ -296,9 +329,11 @@ class ApplicationServiceTransactionWorkerStore(
 
         events = await self.get_events_as_list(event_ids)
 
-        return AppServiceTransaction(service=service, id=entry["txn_id"], events=events)
+        return AppServiceTransaction(
+            service=service, id=entry["txn_id"], events=events, ephemeral=[]
+        )
 
-    def _get_last_txn(self, txn, service_id):
+    def _get_last_txn(self, txn, service_id: Optional[str]) -> int:
         txn.execute(
             "SELECT last_txn FROM application_services_state WHERE as_id=?",
             (service_id,),
@@ -309,7 +344,7 @@ class ApplicationServiceTransactionWorkerStore(
         else:
             return int(last_txn_id[0])  # select 'last_txn' col
 
-    async def set_appservice_last_pos(self, pos) -> None:
+    async def set_appservice_last_pos(self, pos: int) -> None:
         def set_appservice_last_pos_txn(txn):
             txn.execute(
                 "UPDATE appservice_stream_position SET stream_ordering = ?", (pos,)
@@ -319,8 +354,10 @@ class ApplicationServiceTransactionWorkerStore(
             "set_appservice_last_pos", set_appservice_last_pos_txn
         )
 
-    async def get_new_events_for_appservice(self, current_id, limit):
-        """Get all new evnets"""
+    async def get_new_events_for_appservice(
+        self, current_id: int, limit: int
+    ) -> Tuple[int, List[EventBase]]:
+        """Get all new events for an appservice"""
 
         def get_new_events_for_appservice_txn(txn):
             sql = (
@@ -351,6 +388,54 @@ class ApplicationServiceTransactionWorkerStore(
 
         return upper_bound, events
 
+    async def get_type_stream_id_for_appservice(
+        self, service: ApplicationService, type: str
+    ) -> int:
+        if type not in ("read_receipt", "presence"):
+            raise ValueError(
+                "Expected type to be a valid application stream id type, got %s"
+                % (type,)
+            )
+
+        def get_type_stream_id_for_appservice_txn(txn):
+            stream_id_type = "%s_stream_id" % type
+            txn.execute(
+                # We do NOT want to escape `stream_id_type`.
+                "SELECT %s FROM application_services_state WHERE as_id=?"
+                % stream_id_type,
+                (service.id,),
+            )
+            last_stream_id = txn.fetchone()
+            if last_stream_id is None or last_stream_id[0] is None:  # no row exists
+                return 0
+            else:
+                return int(last_stream_id[0])
+
+        return await self.db_pool.runInteraction(
+            "get_type_stream_id_for_appservice", get_type_stream_id_for_appservice_txn
+        )
+
+    async def set_type_stream_id_for_appservice(
+        self, service: ApplicationService, type: str, pos: Optional[int]
+    ) -> None:
+        if type not in ("read_receipt", "presence"):
+            raise ValueError(
+                "Expected type to be a valid application stream id type, got %s"
+                % (type,)
+            )
+
+        def set_type_stream_id_for_appservice_txn(txn):
+            stream_id_type = "%s_stream_id" % type
+            txn.execute(
+                "UPDATE application_services_state SET %s = ? WHERE as_id=?"
+                % stream_id_type,
+                (pos, service.id),
+            )
+
+        await self.db_pool.runInteraction(
+            "set_type_stream_id_for_appservice", set_type_stream_id_for_appservice_txn
+        )
+
 
 class ApplicationServiceTransactionStore(ApplicationServiceTransactionWorkerStore):
     # This is currently empty due to there not being any AS storage functions
diff --git a/synapse/storage/databases/main/censor_events.py b/synapse/storage/databases/main/censor_events.py
index f211ddbaf8..3e26d5ba87 100644
--- a/synapse/storage/databases/main/censor_events.py
+++ b/synapse/storage/databases/main/censor_events.py
@@ -17,12 +17,12 @@ import logging
 from typing import TYPE_CHECKING
 
 from synapse.events.utils import prune_event_dict
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.database import DatabasePool
 from synapse.storage.databases.main.cache import CacheInvalidationWorkerStore
-from synapse.storage.databases.main.events import encode_json
 from synapse.storage.databases.main.events_worker import EventsWorkerStore
+from synapse.util import json_encoder
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -35,14 +35,13 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
     def __init__(self, database: DatabasePool, db_conn, hs: "HomeServer"):
         super().__init__(database, db_conn, hs)
 
-        def _censor_redactions():
-            return run_as_background_process(
-                "_censor_redactions", self._censor_redactions
-            )
-
-        if self.hs.config.redaction_retention_period is not None:
-            hs.get_clock().looping_call(_censor_redactions, 5 * 60 * 1000)
+        if (
+            hs.config.run_background_tasks
+            and self.hs.config.redaction_retention_period is not None
+        ):
+            hs.get_clock().looping_call(self._censor_redactions, 5 * 60 * 1000)
 
+    @wrap_as_background_process("_censor_redactions")
     async def _censor_redactions(self):
         """Censors all redactions older than the configured period that haven't
         been censored yet.
@@ -105,7 +104,7 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
                 and original_event.internal_metadata.is_redacted()
             ):
                 # Redaction was allowed
-                pruned_json = encode_json(
+                pruned_json = json_encoder.encode(
                     prune_event_dict(
                         original_event.room_version, original_event.get_dict()
                     )
@@ -171,7 +170,7 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
                 return
 
             # Prune the event's dict then convert it to JSON.
-            pruned_json = encode_json(
+            pruned_json = json_encoder.encode(
                 prune_event_dict(event.room_version, event.get_dict())
             )
 
diff --git a/synapse/storage/databases/main/client_ips.py b/synapse/storage/databases/main/client_ips.py
index 239c7a949c..339bd691a4 100644
--- a/synapse/storage/databases/main/client_ips.py
+++ b/synapse/storage/databases/main/client_ips.py
@@ -19,7 +19,7 @@ from typing import Dict, Optional, Tuple
 from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.database import DatabasePool, make_tuple_comparison_clause
-from synapse.util.caches.descriptors import Cache
+from synapse.util.caches.lrucache import LruCache
 
 logger = logging.getLogger(__name__)
 
@@ -351,17 +351,71 @@ class ClientIpBackgroundUpdateStore(SQLBaseStore):
         return updated
 
 
-class ClientIpStore(ClientIpBackgroundUpdateStore):
+class ClientIpWorkerStore(ClientIpBackgroundUpdateStore):
     def __init__(self, database: DatabasePool, db_conn, hs):
-
-        self.client_ip_last_seen = Cache(
-            name="client_ip_last_seen", keylen=4, max_entries=50000
-        )
-
         super().__init__(database, db_conn, hs)
 
         self.user_ips_max_age = hs.config.user_ips_max_age
 
+        if hs.config.run_background_tasks and self.user_ips_max_age:
+            self._clock.looping_call(self._prune_old_user_ips, 5 * 1000)
+
+    @wrap_as_background_process("prune_old_user_ips")
+    async def _prune_old_user_ips(self):
+        """Removes entries in user IPs older than the configured period.
+        """
+
+        if self.user_ips_max_age is None:
+            # Nothing to do
+            return
+
+        if not await self.db_pool.updates.has_completed_background_update(
+            "devices_last_seen"
+        ):
+            # Only start pruning if we have finished populating the devices
+            # last seen info.
+            return
+
+        # We do a slightly funky SQL delete to ensure we don't try and delete
+        # too much at once (as the table may be very large from before we
+        # started pruning).
+        #
+        # This works by finding the max last_seen that is less than the given
+        # time, but has no more than N rows before it, deleting all rows with
+        # a lesser last_seen time. (We COALESCE so that the sub-SELECT always
+        # returns exactly one row).
+        sql = """
+            DELETE FROM user_ips
+            WHERE last_seen <= (
+                SELECT COALESCE(MAX(last_seen), -1)
+                FROM (
+                    SELECT last_seen FROM user_ips
+                    WHERE last_seen <= ?
+                    ORDER BY last_seen ASC
+                    LIMIT 5000
+                ) AS u
+            )
+        """
+
+        timestamp = self.clock.time_msec() - self.user_ips_max_age
+
+        def _prune_old_user_ips_txn(txn):
+            txn.execute(sql, (timestamp,))
+
+        await self.db_pool.runInteraction(
+            "_prune_old_user_ips", _prune_old_user_ips_txn
+        )
+
+
+class ClientIpStore(ClientIpWorkerStore):
+    def __init__(self, database: DatabasePool, db_conn, hs):
+
+        self.client_ip_last_seen = LruCache(
+            cache_name="client_ip_last_seen", keylen=4, max_size=50000
+        )
+
+        super().__init__(database, db_conn, hs)
+
         # (user_id, access_token, ip,) -> (user_agent, device_id, last_seen)
         self._batch_row_update = {}
 
@@ -372,9 +426,6 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
             "before", "shutdown", self._update_client_ips_batch
         )
 
-        if self.user_ips_max_age:
-            self._clock.looping_call(self._prune_old_user_ips, 5 * 1000)
-
     async def insert_client_ip(
         self, user_id, access_token, ip, user_agent, device_id, now=None
     ):
@@ -391,7 +442,7 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
         if last_seen is not None and (now - last_seen) < LAST_SEEN_GRANULARITY:
             return
 
-        self.client_ip_last_seen.prefill(key, now)
+        self.client_ip_last_seen.set(key, now)
 
         self._batch_row_update[key] = (user_agent, device_id, now)
 
@@ -525,49 +576,3 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
             }
             for (access_token, ip), (user_agent, last_seen) in results.items()
         ]
-
-    @wrap_as_background_process("prune_old_user_ips")
-    async def _prune_old_user_ips(self):
-        """Removes entries in user IPs older than the configured period.
-        """
-
-        if self.user_ips_max_age is None:
-            # Nothing to do
-            return
-
-        if not await self.db_pool.updates.has_completed_background_update(
-            "devices_last_seen"
-        ):
-            # Only start pruning if we have finished populating the devices
-            # last seen info.
-            return
-
-        # We do a slightly funky SQL delete to ensure we don't try and delete
-        # too much at once (as the table may be very large from before we
-        # started pruning).
-        #
-        # This works by finding the max last_seen that is less than the given
-        # time, but has no more than N rows before it, deleting all rows with
-        # a lesser last_seen time. (We COALESCE so that the sub-SELECT always
-        # returns exactly one row).
-        sql = """
-            DELETE FROM user_ips
-            WHERE last_seen <= (
-                SELECT COALESCE(MAX(last_seen), -1)
-                FROM (
-                    SELECT last_seen FROM user_ips
-                    WHERE last_seen <= ?
-                    ORDER BY last_seen ASC
-                    LIMIT 5000
-                ) AS u
-            )
-        """
-
-        timestamp = self.clock.time_msec() - self.user_ips_max_age
-
-        def _prune_old_user_ips_txn(txn):
-            txn.execute(sql, (timestamp,))
-
-        await self.db_pool.runInteraction(
-            "_prune_old_user_ips", _prune_old_user_ips_txn
-        )
diff --git a/synapse/storage/databases/main/devices.py b/synapse/storage/databases/main/devices.py
index fdf394c612..dfb4f87b8f 100644
--- a/synapse/storage/databases/main/devices.py
+++ b/synapse/storage/databases/main/devices.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2016 OpenMarket Ltd
 # Copyright 2019 New Vector Ltd
-# Copyright 2019 The Matrix.org Foundation C.I.C.
+# Copyright 2019,2020 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -25,7 +25,7 @@ from synapse.logging.opentracing import (
     trace,
     whitelisted_homeserver,
 )
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
 from synapse.storage.database import (
     DatabasePool,
@@ -33,8 +33,9 @@ from synapse.storage.database import (
     make_tuple_comparison_clause,
 )
 from synapse.types import Collection, JsonDict, get_verify_key_from_cross_signing_key
-from synapse.util import json_encoder
-from synapse.util.caches.descriptors import Cache, cached, cachedList
+from synapse.util import json_decoder, json_encoder
+from synapse.util.caches.descriptors import cached, cachedList
+from synapse.util.caches.lrucache import LruCache
 from synapse.util.iterutils import batch_iter
 from synapse.util.stringutils import shortstr
 
@@ -48,6 +49,14 @@ BG_UPDATE_REMOVE_DUP_OUTBOUND_POKES = "remove_dup_outbound_pokes"
 
 
 class DeviceWorkerStore(SQLBaseStore):
+    def __init__(self, database: DatabasePool, db_conn, hs):
+        super().__init__(database, db_conn, hs)
+
+        if hs.config.run_background_tasks:
+            self._clock.looping_call(
+                self._prune_old_outbound_device_pokes, 60 * 60 * 1000
+            )
+
     async def get_device(self, user_id: str, device_id: str) -> Dict[str, Any]:
         """Retrieve a device. Only returns devices that are not marked as
         hidden.
@@ -698,6 +707,172 @@ class DeviceWorkerStore(SQLBaseStore):
             _mark_remote_user_device_list_as_unsubscribed_txn,
         )
 
+    async def get_dehydrated_device(
+        self, user_id: str
+    ) -> Optional[Tuple[str, JsonDict]]:
+        """Retrieve the information for a dehydrated device.
+
+        Args:
+            user_id: the user whose dehydrated device we are looking for
+        Returns:
+            a tuple whose first item is the device ID, and the second item is
+            the dehydrated device information
+        """
+        # FIXME: make sure device ID still exists in devices table
+        row = await self.db_pool.simple_select_one(
+            table="dehydrated_devices",
+            keyvalues={"user_id": user_id},
+            retcols=["device_id", "device_data"],
+            allow_none=True,
+        )
+        return (
+            (row["device_id"], json_decoder.decode(row["device_data"])) if row else None
+        )
+
+    def _store_dehydrated_device_txn(
+        self, txn, user_id: str, device_id: str, device_data: str
+    ) -> Optional[str]:
+        old_device_id = self.db_pool.simple_select_one_onecol_txn(
+            txn,
+            table="dehydrated_devices",
+            keyvalues={"user_id": user_id},
+            retcol="device_id",
+            allow_none=True,
+        )
+        self.db_pool.simple_upsert_txn(
+            txn,
+            table="dehydrated_devices",
+            keyvalues={"user_id": user_id},
+            values={"device_id": device_id, "device_data": device_data},
+        )
+        return old_device_id
+
+    async def store_dehydrated_device(
+        self, user_id: str, device_id: str, device_data: JsonDict
+    ) -> Optional[str]:
+        """Store a dehydrated device for a user.
+
+        Args:
+            user_id: the user that we are storing the device for
+            device_id: the ID of the dehydrated device
+            device_data: the dehydrated device information
+        Returns:
+            device id of the user's previous dehydrated device, if any
+        """
+        return await self.db_pool.runInteraction(
+            "store_dehydrated_device_txn",
+            self._store_dehydrated_device_txn,
+            user_id,
+            device_id,
+            json_encoder.encode(device_data),
+        )
+
+    async def remove_dehydrated_device(self, user_id: str, device_id: str) -> bool:
+        """Remove a dehydrated device.
+
+        Args:
+            user_id: the user that the dehydrated device belongs to
+            device_id: the ID of the dehydrated device
+        """
+        count = await self.db_pool.simple_delete(
+            "dehydrated_devices",
+            {"user_id": user_id, "device_id": device_id},
+            desc="remove_dehydrated_device",
+        )
+        return count >= 1
+
+    @wrap_as_background_process("prune_old_outbound_device_pokes")
+    async def _prune_old_outbound_device_pokes(
+        self, prune_age: int = 24 * 60 * 60 * 1000
+    ) -> None:
+        """Delete old entries out of the device_lists_outbound_pokes to ensure
+        that we don't fill up due to dead servers.
+
+        Normally, we try to send device updates as a delta since a previous known point:
+        this is done by setting the prev_id in the m.device_list_update EDU. However,
+        for that to work, we have to have a complete record of each change to
+        each device, which can add up to quite a lot of data.
+
+        An alternative mechanism is that, if the remote server sees that it has missed
+        an entry in the stream_id sequence for a given user, it will request a full
+        list of that user's devices. Hence, we can reduce the amount of data we have to
+        store (and transmit in some future transaction), by clearing almost everything
+        for a given destination out of the database, and having the remote server
+        resync.
+
+        All we need to do is make sure we keep at least one row for each
+        (user, destination) pair, to remind us to send a m.device_list_update EDU for
+        that user when the destination comes back. It doesn't matter which device
+        we keep.
+        """
+        yesterday = self._clock.time_msec() - prune_age
+
+        def _prune_txn(txn):
+            # look for (user, destination) pairs which have an update older than
+            # the cutoff.
+            #
+            # For each pair, we also need to know the most recent stream_id, and
+            # an arbitrary device_id at that stream_id.
+            select_sql = """
+            SELECT
+                dlop1.destination,
+                dlop1.user_id,
+                MAX(dlop1.stream_id) AS stream_id,
+                (SELECT MIN(dlop2.device_id) AS device_id FROM
+                    device_lists_outbound_pokes dlop2
+                    WHERE dlop2.destination = dlop1.destination AND
+                      dlop2.user_id=dlop1.user_id AND
+                      dlop2.stream_id=MAX(dlop1.stream_id)
+                )
+            FROM device_lists_outbound_pokes dlop1
+                GROUP BY destination, user_id
+                HAVING min(ts) < ? AND count(*) > 1
+            """
+
+            txn.execute(select_sql, (yesterday,))
+            rows = txn.fetchall()
+
+            if not rows:
+                return
+
+            logger.info(
+                "Pruning old outbound device list updates for %i users/destinations: %s",
+                len(rows),
+                shortstr((row[0], row[1]) for row in rows),
+            )
+
+            # we want to keep the update with the highest stream_id for each user.
+            #
+            # there might be more than one update (with different device_ids) with the
+            # same stream_id, so we also delete all but one rows with the max stream id.
+            delete_sql = """
+                DELETE FROM device_lists_outbound_pokes
+                WHERE destination = ? AND user_id = ? AND (
+                    stream_id < ? OR
+                    (stream_id = ? AND device_id != ?)
+                )
+            """
+            count = 0
+            for (destination, user_id, stream_id, device_id) in rows:
+                txn.execute(
+                    delete_sql, (destination, user_id, stream_id, stream_id, device_id)
+                )
+                count += txn.rowcount
+
+            # Since we've deleted unsent deltas, we need to remove the entry
+            # of last successful sent so that the prev_ids are correctly set.
+            sql = """
+                DELETE FROM device_lists_outbound_last_success
+                WHERE destination = ? AND user_id = ?
+            """
+            txn.executemany(sql, ((row[0], row[1]) for row in rows))
+
+            logger.info("Pruned %d device list outbound pokes", count)
+
+        await self.db_pool.runInteraction(
+            "_prune_old_outbound_device_pokes", _prune_txn,
+        )
+
 
 class DeviceBackgroundUpdateStore(SQLBaseStore):
     def __init__(self, database: DatabasePool, db_conn, hs):
@@ -830,14 +1005,12 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
 
         # Map of (user_id, device_id) -> bool. If there is an entry that implies
         # the device exists.
-        self.device_id_exists_cache = Cache(
-            name="device_id_exists", keylen=2, max_entries=10000
+        self.device_id_exists_cache = LruCache(
+            cache_name="device_id_exists", keylen=2, max_size=10000
         )
 
-        self._clock.looping_call(self._prune_old_outbound_device_pokes, 60 * 60 * 1000)
-
     async def store_device(
-        self, user_id: str, device_id: str, initial_device_display_name: str
+        self, user_id: str, device_id: str, initial_device_display_name: Optional[str]
     ) -> bool:
         """Ensure the given device is known; add it to the store if not
 
@@ -879,7 +1052,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
                 )
                 if hidden:
                     raise StoreError(400, "The device ID is in use", Codes.FORBIDDEN)
-            self.device_id_exists_cache.prefill(key, True)
+            self.device_id_exists_cache.set(key, True)
             return inserted
         except StoreError:
             raise
@@ -955,7 +1128,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         )
 
     async def update_remote_device_list_cache_entry(
-        self, user_id: str, device_id: str, content: JsonDict, stream_id: int
+        self, user_id: str, device_id: str, content: JsonDict, stream_id: str
     ) -> None:
         """Updates a single device in the cache of a remote user's devicelist.
 
@@ -983,7 +1156,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         user_id: str,
         device_id: str,
         content: JsonDict,
-        stream_id: int,
+        stream_id: str,
     ) -> None:
         if content.get("deleted"):
             self.db_pool.simple_delete_txn(
@@ -1193,95 +1366,3 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
                 for device_id in device_ids
             ],
         )
-
-    def _prune_old_outbound_device_pokes(self, prune_age: int = 24 * 60 * 60 * 1000):
-        """Delete old entries out of the device_lists_outbound_pokes to ensure
-        that we don't fill up due to dead servers.
-
-        Normally, we try to send device updates as a delta since a previous known point:
-        this is done by setting the prev_id in the m.device_list_update EDU. However,
-        for that to work, we have to have a complete record of each change to
-        each device, which can add up to quite a lot of data.
-
-        An alternative mechanism is that, if the remote server sees that it has missed
-        an entry in the stream_id sequence for a given user, it will request a full
-        list of that user's devices. Hence, we can reduce the amount of data we have to
-        store (and transmit in some future transaction), by clearing almost everything
-        for a given destination out of the database, and having the remote server
-        resync.
-
-        All we need to do is make sure we keep at least one row for each
-        (user, destination) pair, to remind us to send a m.device_list_update EDU for
-        that user when the destination comes back. It doesn't matter which device
-        we keep.
-        """
-        yesterday = self._clock.time_msec() - prune_age
-
-        def _prune_txn(txn):
-            # look for (user, destination) pairs which have an update older than
-            # the cutoff.
-            #
-            # For each pair, we also need to know the most recent stream_id, and
-            # an arbitrary device_id at that stream_id.
-            select_sql = """
-            SELECT
-                dlop1.destination,
-                dlop1.user_id,
-                MAX(dlop1.stream_id) AS stream_id,
-                (SELECT MIN(dlop2.device_id) AS device_id FROM
-                    device_lists_outbound_pokes dlop2
-                    WHERE dlop2.destination = dlop1.destination AND
-                      dlop2.user_id=dlop1.user_id AND
-                      dlop2.stream_id=MAX(dlop1.stream_id)
-                )
-            FROM device_lists_outbound_pokes dlop1
-                GROUP BY destination, user_id
-                HAVING min(ts) < ? AND count(*) > 1
-            """
-
-            txn.execute(select_sql, (yesterday,))
-            rows = txn.fetchall()
-
-            if not rows:
-                return
-
-            logger.info(
-                "Pruning old outbound device list updates for %i users/destinations: %s",
-                len(rows),
-                shortstr((row[0], row[1]) for row in rows),
-            )
-
-            # we want to keep the update with the highest stream_id for each user.
-            #
-            # there might be more than one update (with different device_ids) with the
-            # same stream_id, so we also delete all but one rows with the max stream id.
-            delete_sql = """
-                DELETE FROM device_lists_outbound_pokes
-                WHERE destination = ? AND user_id = ? AND (
-                    stream_id < ? OR
-                    (stream_id = ? AND device_id != ?)
-                )
-            """
-            count = 0
-            for (destination, user_id, stream_id, device_id) in rows:
-                txn.execute(
-                    delete_sql, (destination, user_id, stream_id, stream_id, device_id)
-                )
-                count += txn.rowcount
-
-            # Since we've deleted unsent deltas, we need to remove the entry
-            # of last successful sent so that the prev_ids are correctly set.
-            sql = """
-                DELETE FROM device_lists_outbound_last_success
-                WHERE destination = ? AND user_id = ?
-            """
-            txn.executemany(sql, ((row[0], row[1]) for row in rows))
-
-            logger.info("Pruned %d device list outbound pokes", count)
-
-        return run_as_background_process(
-            "prune_old_outbound_device_pokes",
-            self.db_pool.runInteraction,
-            "_prune_old_outbound_device_pokes",
-            _prune_txn,
-        )
diff --git a/synapse/storage/databases/main/end_to_end_keys.py b/synapse/storage/databases/main/end_to_end_keys.py
index 22e1ed15d0..4d1b92d1aa 100644
--- a/synapse/storage/databases/main/end_to_end_keys.py
+++ b/synapse/storage/databases/main/end_to_end_keys.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
 # Copyright 2019 New Vector Ltd
-# Copyright 2019 The Matrix.org Foundation C.I.C.
+# Copyright 2019,2020 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -24,7 +24,7 @@ from twisted.enterprise.adbapi import Connection
 
 from synapse.logging.opentracing import log_kv, set_tag, trace
 from synapse.storage._base import SQLBaseStore, db_to_json
-from synapse.storage.database import make_in_list_sql_clause
+from synapse.storage.database import DatabasePool, make_in_list_sql_clause
 from synapse.storage.types import Cursor
 from synapse.types import JsonDict
 from synapse.util import json_encoder
@@ -33,6 +33,7 @@ from synapse.util.iterutils import batch_iter
 
 if TYPE_CHECKING:
     from synapse.handlers.e2e_keys import SignatureListItem
+    from synapse.server import HomeServer
 
 
 @attr.s(slots=True)
@@ -47,7 +48,20 @@ class DeviceKeyLookupResult:
     keys = attr.ib(type=Optional[JsonDict])
 
 
-class EndToEndKeyWorkerStore(SQLBaseStore):
+class EndToEndKeyBackgroundStore(SQLBaseStore):
+    def __init__(self, database: DatabasePool, db_conn: Connection, hs: "HomeServer"):
+        super().__init__(database, db_conn, hs)
+
+        self.db_pool.updates.register_background_index_update(
+            "e2e_cross_signing_keys_idx",
+            index_name="e2e_cross_signing_keys_stream_idx",
+            table="e2e_cross_signing_keys",
+            columns=["stream_id"],
+            unique=True,
+        )
+
+
+class EndToEndKeyWorkerStore(EndToEndKeyBackgroundStore):
     async def get_e2e_device_keys_for_federation_query(
         self, user_id: str
     ) -> Tuple[int, List[JsonDict]]:
@@ -367,6 +381,61 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
             "count_e2e_one_time_keys", _count_e2e_one_time_keys
         )
 
+    async def set_e2e_fallback_keys(
+        self, user_id: str, device_id: str, fallback_keys: JsonDict
+    ) -> None:
+        """Set the user's e2e fallback keys.
+
+        Args:
+            user_id: the user whose keys are being set
+            device_id: the device whose keys are being set
+            fallback_keys: the keys to set.  This is a map from key ID (which is
+                of the form "algorithm:id") to key data.
+        """
+        # fallback_keys will usually only have one item in it, so using a for
+        # loop (as opposed to calling simple_upsert_many_txn) won't be too bad
+        # FIXME: make sure that only one key per algorithm is uploaded
+        for key_id, fallback_key in fallback_keys.items():
+            algorithm, key_id = key_id.split(":", 1)
+            await self.db_pool.simple_upsert(
+                "e2e_fallback_keys_json",
+                keyvalues={
+                    "user_id": user_id,
+                    "device_id": device_id,
+                    "algorithm": algorithm,
+                },
+                values={
+                    "key_id": key_id,
+                    "key_json": json_encoder.encode(fallback_key),
+                    "used": False,
+                },
+                desc="set_e2e_fallback_key",
+            )
+
+        await self.invalidate_cache_and_stream(
+            "get_e2e_unused_fallback_key_types", (user_id, device_id)
+        )
+
+    @cached(max_entries=10000)
+    async def get_e2e_unused_fallback_key_types(
+        self, user_id: str, device_id: str
+    ) -> List[str]:
+        """Returns the fallback key types that have an unused key.
+
+        Args:
+            user_id: the user whose keys are being queried
+            device_id: the device whose keys are being queried
+
+        Returns:
+            a list of key types
+        """
+        return await self.db_pool.simple_select_onecol(
+            "e2e_fallback_keys_json",
+            keyvalues={"user_id": user_id, "device_id": device_id, "used": False},
+            retcol="algorithm",
+            desc="get_e2e_unused_fallback_key_types",
+        )
+
     async def get_e2e_cross_signing_key(
         self, user_id: str, key_type: str, from_user_id: Optional[str] = None
     ) -> Optional[dict]:
@@ -701,15 +770,37 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
                 " WHERE user_id = ? AND device_id = ? AND algorithm = ?"
                 " LIMIT 1"
             )
+            fallback_sql = (
+                "SELECT key_id, key_json, used FROM e2e_fallback_keys_json"
+                " WHERE user_id = ? AND device_id = ? AND algorithm = ?"
+                " LIMIT 1"
+            )
             result = {}
             delete = []
+            used_fallbacks = []
             for user_id, device_id, algorithm in query_list:
                 user_result = result.setdefault(user_id, {})
                 device_result = user_result.setdefault(device_id, {})
                 txn.execute(sql, (user_id, device_id, algorithm))
-                for key_id, key_json in txn:
+                otk_row = txn.fetchone()
+                if otk_row is not None:
+                    key_id, key_json = otk_row
                     device_result[algorithm + ":" + key_id] = key_json
                     delete.append((user_id, device_id, algorithm, key_id))
+                else:
+                    # no one-time key available, so see if there's a fallback
+                    # key
+                    txn.execute(fallback_sql, (user_id, device_id, algorithm))
+                    fallback_row = txn.fetchone()
+                    if fallback_row is not None:
+                        key_id, key_json, used = fallback_row
+                        device_result[algorithm + ":" + key_id] = key_json
+                        if not used:
+                            used_fallbacks.append(
+                                (user_id, device_id, algorithm, key_id)
+                            )
+
+            # drop any one-time keys that were claimed
             sql = (
                 "DELETE FROM e2e_one_time_keys_json"
                 " WHERE user_id = ? AND device_id = ? AND algorithm = ?"
@@ -726,6 +817,23 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
                 self._invalidate_cache_and_stream(
                     txn, self.count_e2e_one_time_keys, (user_id, device_id)
                 )
+            # mark fallback keys as used
+            for user_id, device_id, algorithm, key_id in used_fallbacks:
+                self.db_pool.simple_update_txn(
+                    txn,
+                    "e2e_fallback_keys_json",
+                    {
+                        "user_id": user_id,
+                        "device_id": device_id,
+                        "algorithm": algorithm,
+                        "key_id": key_id,
+                    },
+                    {"used": True},
+                )
+                self._invalidate_cache_and_stream(
+                    txn, self.get_e2e_unused_fallback_key_types, (user_id, device_id)
+                )
+
             return result
 
         return await self.db_pool.runInteraction(
@@ -754,6 +862,19 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
             self._invalidate_cache_and_stream(
                 txn, self.count_e2e_one_time_keys, (user_id, device_id)
             )
+            self.db_pool.simple_delete_txn(
+                txn,
+                table="dehydrated_devices",
+                keyvalues={"user_id": user_id, "device_id": device_id},
+            )
+            self.db_pool.simple_delete_txn(
+                txn,
+                table="e2e_fallback_keys_json",
+                keyvalues={"user_id": user_id, "device_id": device_id},
+            )
+            self._invalidate_cache_and_stream(
+                txn, self.get_e2e_unused_fallback_key_types, (user_id, device_id)
+            )
 
         await self.db_pool.runInteraction(
             "delete_e2e_keys_by_device", delete_e2e_keys_by_device_txn
diff --git a/synapse/storage/databases/main/event_federation.py b/synapse/storage/databases/main/event_federation.py
index 6d3689c09e..2e07c37340 100644
--- a/synapse/storage/databases/main/event_federation.py
+++ b/synapse/storage/databases/main/event_federation.py
@@ -19,19 +19,33 @@ from typing import Dict, Iterable, List, Set, Tuple
 
 from synapse.api.errors import StoreError
 from synapse.events import EventBase
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage._base import SQLBaseStore, make_in_list_sql_clause
 from synapse.storage.database import DatabasePool, LoggingTransaction
 from synapse.storage.databases.main.events_worker import EventsWorkerStore
 from synapse.storage.databases.main.signatures import SignatureWorkerStore
 from synapse.types import Collection
 from synapse.util.caches.descriptors import cached
+from synapse.util.caches.lrucache import LruCache
 from synapse.util.iterutils import batch_iter
 
 logger = logging.getLogger(__name__)
 
 
 class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBaseStore):
+    def __init__(self, database: DatabasePool, db_conn, hs):
+        super().__init__(database, db_conn, hs)
+
+        if hs.config.run_background_tasks:
+            hs.get_clock().looping_call(
+                self._delete_old_forward_extrem_cache, 60 * 60 * 1000
+            )
+
+        # Cache of event ID to list of auth event IDs and their depths.
+        self._event_auth_cache = LruCache(
+            500000, "_event_auth_cache", size_callback=len
+        )  # type: LruCache[str, List[Tuple[str, int]]]
+
     async def get_auth_chain(
         self, event_ids: Collection[str], include_given: bool = False
     ) -> List[EventBase]:
@@ -76,17 +90,45 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         else:
             results = set()
 
-        base_sql = "SELECT DISTINCT auth_id FROM event_auth WHERE "
+        # We pull out the depth simply so that we can populate the
+        # `_event_auth_cache` cache.
+        base_sql = """
+            SELECT a.event_id, auth_id, depth
+            FROM event_auth AS a
+            INNER JOIN events AS e ON (e.event_id = a.auth_id)
+            WHERE
+        """
 
         front = set(event_ids)
         while front:
             new_front = set()
             for chunk in batch_iter(front, 100):
-                clause, args = make_in_list_sql_clause(
-                    txn.database_engine, "event_id", chunk
-                )
-                txn.execute(base_sql + clause, args)
-                new_front.update(r[0] for r in txn)
+                # Pull the auth events either from the cache or DB.
+                to_fetch = []  # Event IDs to fetch from DB  # type: List[str]
+                for event_id in chunk:
+                    res = self._event_auth_cache.get(event_id)
+                    if res is None:
+                        to_fetch.append(event_id)
+                    else:
+                        new_front.update(auth_id for auth_id, depth in res)
+
+                if to_fetch:
+                    clause, args = make_in_list_sql_clause(
+                        txn.database_engine, "a.event_id", to_fetch
+                    )
+                    txn.execute(base_sql + clause, args)
+
+                    # Note we need to batch up the results by event ID before
+                    # adding to the cache.
+                    to_cache = {}
+                    for event_id, auth_event_id, auth_event_depth in txn:
+                        to_cache.setdefault(event_id, []).append(
+                            (auth_event_id, auth_event_depth)
+                        )
+                        new_front.add(auth_event_id)
+
+                    for event_id, auth_events in to_cache.items():
+                        self._event_auth_cache.set(event_id, auth_events)
 
             new_front -= results
 
@@ -205,14 +247,38 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
                 break
 
             # Fetch the auth events and their depths of the N last events we're
-            # currently walking
+            # currently walking, either from cache or DB.
             search, chunk = search[:-100], search[-100:]
-            clause, args = make_in_list_sql_clause(
-                txn.database_engine, "a.event_id", [e_id for _, e_id in chunk]
-            )
-            txn.execute(base_sql + clause, args)
 
-            for event_id, auth_event_id, auth_event_depth in txn:
+            found = []  # Results found  # type: List[Tuple[str, str, int]]
+            to_fetch = []  # Event IDs to fetch from DB  # type: List[str]
+            for _, event_id in chunk:
+                res = self._event_auth_cache.get(event_id)
+                if res is None:
+                    to_fetch.append(event_id)
+                else:
+                    found.extend((event_id, auth_id, depth) for auth_id, depth in res)
+
+            if to_fetch:
+                clause, args = make_in_list_sql_clause(
+                    txn.database_engine, "a.event_id", to_fetch
+                )
+                txn.execute(base_sql + clause, args)
+
+                # We parse the results and add the to the `found` set and the
+                # cache (note we need to batch up the results by event ID before
+                # adding to the cache).
+                to_cache = {}
+                for event_id, auth_event_id, auth_event_depth in txn:
+                    to_cache.setdefault(event_id, []).append(
+                        (auth_event_id, auth_event_depth)
+                    )
+                    found.append((event_id, auth_event_id, auth_event_depth))
+
+                for event_id, auth_events in to_cache.items():
+                    self._event_auth_cache.set(event_id, auth_events)
+
+            for event_id, auth_event_id, auth_event_depth in found:
                 event_to_auth_events.setdefault(event_id, set()).add(auth_event_id)
 
                 sets = event_to_missing_sets.get(auth_event_id)
@@ -586,6 +652,28 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
 
         return [row["event_id"] for row in rows]
 
+    @wrap_as_background_process("delete_old_forward_extrem_cache")
+    async def _delete_old_forward_extrem_cache(self) -> None:
+        def _delete_old_forward_extrem_cache_txn(txn):
+            # Delete entries older than a month, while making sure we don't delete
+            # the only entries for a room.
+            sql = """
+                DELETE FROM stream_ordering_to_exterm
+                WHERE
+                room_id IN (
+                    SELECT room_id
+                    FROM stream_ordering_to_exterm
+                    WHERE stream_ordering > ?
+                ) AND stream_ordering < ?
+            """
+            txn.execute(
+                sql, (self.stream_ordering_month_ago, self.stream_ordering_month_ago)
+            )
+
+        await self.db_pool.runInteraction(
+            "_delete_old_forward_extrem_cache", _delete_old_forward_extrem_cache_txn,
+        )
+
 
 class EventFederationStore(EventFederationWorkerStore):
     """ Responsible for storing and serving up the various graphs associated
@@ -606,34 +694,6 @@ class EventFederationStore(EventFederationWorkerStore):
             self.EVENT_AUTH_STATE_ONLY, self._background_delete_non_state_event_auth
         )
 
-        hs.get_clock().looping_call(
-            self._delete_old_forward_extrem_cache, 60 * 60 * 1000
-        )
-
-    def _delete_old_forward_extrem_cache(self):
-        def _delete_old_forward_extrem_cache_txn(txn):
-            # Delete entries older than a month, while making sure we don't delete
-            # the only entries for a room.
-            sql = """
-                DELETE FROM stream_ordering_to_exterm
-                WHERE
-                room_id IN (
-                    SELECT room_id
-                    FROM stream_ordering_to_exterm
-                    WHERE stream_ordering > ?
-                ) AND stream_ordering < ?
-            """
-            txn.execute(
-                sql, (self.stream_ordering_month_ago, self.stream_ordering_month_ago)
-            )
-
-        return run_as_background_process(
-            "delete_old_forward_extrem_cache",
-            self.db_pool.runInteraction,
-            "_delete_old_forward_extrem_cache",
-            _delete_old_forward_extrem_cache_txn,
-        )
-
     async def clean_room_for_join(self, room_id):
         return await self.db_pool.runInteraction(
             "clean_room_for_join", self._clean_room_for_join_txn, room_id
diff --git a/synapse/storage/databases/main/event_push_actions.py b/synapse/storage/databases/main/event_push_actions.py
index 62f1738732..2e56dfaf31 100644
--- a/synapse/storage/databases/main/event_push_actions.py
+++ b/synapse/storage/databases/main/event_push_actions.py
@@ -13,15 +13,14 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import logging
 from typing import Dict, List, Optional, Tuple, Union
 
 import attr
 
-from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.storage._base import LoggingTransaction, SQLBaseStore, db_to_json
-from synapse.storage.database import DatabasePool
+from synapse.metrics.background_process_metrics import wrap_as_background_process
+from synapse.storage._base import SQLBaseStore, db_to_json
+from synapse.storage.database import DatabasePool, LoggingTransaction
 from synapse.util import json_encoder
 from synapse.util.caches.descriptors import cached
 
@@ -74,19 +73,21 @@ class EventPushActionsWorkerStore(SQLBaseStore):
         self.stream_ordering_month_ago = None
         self.stream_ordering_day_ago = None
 
-        cur = LoggingTransaction(
-            db_conn.cursor(),
-            name="_find_stream_orderings_for_times_txn",
-            database_engine=self.database_engine,
-        )
+        cur = db_conn.cursor(txn_name="_find_stream_orderings_for_times_txn")
         self._find_stream_orderings_for_times_txn(cur)
         cur.close()
 
         self.find_stream_orderings_looping_call = self._clock.looping_call(
             self._find_stream_orderings_for_times, 10 * 60 * 1000
         )
+
         self._rotate_delay = 3
         self._rotate_count = 10000
+        self._doing_notif_rotation = False
+        if hs.config.run_background_tasks:
+            self._rotate_notif_loop = self._clock.looping_call(
+                self._rotate_notifs, 30 * 60 * 1000
+            )
 
     @cached(num_args=3, tree=True, max_entries=5000)
     async def get_unread_event_push_actions_by_room_for_user(
@@ -518,15 +519,14 @@ class EventPushActionsWorkerStore(SQLBaseStore):
                 "Error removing push actions after event persistence failure"
             )
 
-    def _find_stream_orderings_for_times(self):
-        return run_as_background_process(
-            "event_push_action_stream_orderings",
-            self.db_pool.runInteraction,
+    @wrap_as_background_process("event_push_action_stream_orderings")
+    async def _find_stream_orderings_for_times(self) -> None:
+        await self.db_pool.runInteraction(
             "_find_stream_orderings_for_times",
             self._find_stream_orderings_for_times_txn,
         )
 
-    def _find_stream_orderings_for_times_txn(self, txn):
+    def _find_stream_orderings_for_times_txn(self, txn: LoggingTransaction) -> None:
         logger.info("Searching for stream ordering 1 month ago")
         self.stream_ordering_month_ago = self._find_first_stream_ordering_after_ts_txn(
             txn, self._clock.time_msec() - 30 * 24 * 60 * 60 * 1000
@@ -656,129 +656,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
         )
         return result[0] if result else None
 
-
-class EventPushActionsStore(EventPushActionsWorkerStore):
-    EPA_HIGHLIGHT_INDEX = "epa_highlight_index"
-
-    def __init__(self, database: DatabasePool, db_conn, hs):
-        super().__init__(database, db_conn, hs)
-
-        self.db_pool.updates.register_background_index_update(
-            self.EPA_HIGHLIGHT_INDEX,
-            index_name="event_push_actions_u_highlight",
-            table="event_push_actions",
-            columns=["user_id", "stream_ordering"],
-        )
-
-        self.db_pool.updates.register_background_index_update(
-            "event_push_actions_highlights_index",
-            index_name="event_push_actions_highlights_index",
-            table="event_push_actions",
-            columns=["user_id", "room_id", "topological_ordering", "stream_ordering"],
-            where_clause="highlight=1",
-        )
-
-        self._doing_notif_rotation = False
-        self._rotate_notif_loop = self._clock.looping_call(
-            self._start_rotate_notifs, 30 * 60 * 1000
-        )
-
-    async def get_push_actions_for_user(
-        self, user_id, before=None, limit=50, only_highlight=False
-    ):
-        def f(txn):
-            before_clause = ""
-            if before:
-                before_clause = "AND epa.stream_ordering < ?"
-                args = [user_id, before, limit]
-            else:
-                args = [user_id, limit]
-
-            if only_highlight:
-                if len(before_clause) > 0:
-                    before_clause += " "
-                before_clause += "AND epa.highlight = 1"
-
-            # NB. This assumes event_ids are globally unique since
-            # it makes the query easier to index
-            sql = (
-                "SELECT epa.event_id, epa.room_id,"
-                " epa.stream_ordering, epa.topological_ordering,"
-                " epa.actions, epa.highlight, epa.profile_tag, e.received_ts"
-                " FROM event_push_actions epa, events e"
-                " WHERE epa.event_id = e.event_id"
-                " AND epa.user_id = ? %s"
-                " AND epa.notif = 1"
-                " ORDER BY epa.stream_ordering DESC"
-                " LIMIT ?" % (before_clause,)
-            )
-            txn.execute(sql, args)
-            return self.db_pool.cursor_to_dict(txn)
-
-        push_actions = await self.db_pool.runInteraction("get_push_actions_for_user", f)
-        for pa in push_actions:
-            pa["actions"] = _deserialize_action(pa["actions"], pa["highlight"])
-        return push_actions
-
-    async def get_latest_push_action_stream_ordering(self):
-        def f(txn):
-            txn.execute("SELECT MAX(stream_ordering) FROM event_push_actions")
-            return txn.fetchone()
-
-        result = await self.db_pool.runInteraction(
-            "get_latest_push_action_stream_ordering", f
-        )
-        return result[0] or 0
-
-    def _remove_old_push_actions_before_txn(
-        self, txn, room_id, user_id, stream_ordering
-    ):
-        """
-        Purges old push actions for a user and room before a given
-        stream_ordering.
-
-        We however keep a months worth of highlighted notifications, so that
-        users can still get a list of recent highlights.
-
-        Args:
-            txn: The transcation
-            room_id: Room ID to delete from
-            user_id: user ID to delete for
-            stream_ordering: The lowest stream ordering which will
-                                  not be deleted.
-        """
-        txn.call_after(
-            self.get_unread_event_push_actions_by_room_for_user.invalidate_many,
-            (room_id, user_id),
-        )
-
-        # We need to join on the events table to get the received_ts for
-        # event_push_actions and sqlite won't let us use a join in a delete so
-        # we can't just delete where received_ts < x. Furthermore we can
-        # only identify event_push_actions by a tuple of room_id, event_id
-        # we we can't use a subquery.
-        # Instead, we look up the stream ordering for the last event in that
-        # room received before the threshold time and delete event_push_actions
-        # in the room with a stream_odering before that.
-        txn.execute(
-            "DELETE FROM event_push_actions "
-            " WHERE user_id = ? AND room_id = ? AND "
-            " stream_ordering <= ?"
-            " AND ((stream_ordering < ? AND highlight = 1) or highlight = 0)",
-            (user_id, room_id, stream_ordering, self.stream_ordering_month_ago),
-        )
-
-        txn.execute(
-            """
-            DELETE FROM event_push_summary
-            WHERE room_id = ? AND user_id = ? AND stream_ordering <= ?
-        """,
-            (room_id, user_id, stream_ordering),
-        )
-
-    def _start_rotate_notifs(self):
-        return run_as_background_process("rotate_notifs", self._rotate_notifs)
-
+    @wrap_as_background_process("rotate_notifs")
     async def _rotate_notifs(self):
         if self._doing_notif_rotation or self.stream_ordering_day_ago is None:
             return
@@ -958,6 +836,121 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
         )
 
 
+class EventPushActionsStore(EventPushActionsWorkerStore):
+    EPA_HIGHLIGHT_INDEX = "epa_highlight_index"
+
+    def __init__(self, database: DatabasePool, db_conn, hs):
+        super().__init__(database, db_conn, hs)
+
+        self.db_pool.updates.register_background_index_update(
+            self.EPA_HIGHLIGHT_INDEX,
+            index_name="event_push_actions_u_highlight",
+            table="event_push_actions",
+            columns=["user_id", "stream_ordering"],
+        )
+
+        self.db_pool.updates.register_background_index_update(
+            "event_push_actions_highlights_index",
+            index_name="event_push_actions_highlights_index",
+            table="event_push_actions",
+            columns=["user_id", "room_id", "topological_ordering", "stream_ordering"],
+            where_clause="highlight=1",
+        )
+
+    async def get_push_actions_for_user(
+        self, user_id, before=None, limit=50, only_highlight=False
+    ):
+        def f(txn):
+            before_clause = ""
+            if before:
+                before_clause = "AND epa.stream_ordering < ?"
+                args = [user_id, before, limit]
+            else:
+                args = [user_id, limit]
+
+            if only_highlight:
+                if len(before_clause) > 0:
+                    before_clause += " "
+                before_clause += "AND epa.highlight = 1"
+
+            # NB. This assumes event_ids are globally unique since
+            # it makes the query easier to index
+            sql = (
+                "SELECT epa.event_id, epa.room_id,"
+                " epa.stream_ordering, epa.topological_ordering,"
+                " epa.actions, epa.highlight, epa.profile_tag, e.received_ts"
+                " FROM event_push_actions epa, events e"
+                " WHERE epa.event_id = e.event_id"
+                " AND epa.user_id = ? %s"
+                " AND epa.notif = 1"
+                " ORDER BY epa.stream_ordering DESC"
+                " LIMIT ?" % (before_clause,)
+            )
+            txn.execute(sql, args)
+            return self.db_pool.cursor_to_dict(txn)
+
+        push_actions = await self.db_pool.runInteraction("get_push_actions_for_user", f)
+        for pa in push_actions:
+            pa["actions"] = _deserialize_action(pa["actions"], pa["highlight"])
+        return push_actions
+
+    async def get_latest_push_action_stream_ordering(self):
+        def f(txn):
+            txn.execute("SELECT MAX(stream_ordering) FROM event_push_actions")
+            return txn.fetchone()
+
+        result = await self.db_pool.runInteraction(
+            "get_latest_push_action_stream_ordering", f
+        )
+        return result[0] or 0
+
+    def _remove_old_push_actions_before_txn(
+        self, txn, room_id, user_id, stream_ordering
+    ):
+        """
+        Purges old push actions for a user and room before a given
+        stream_ordering.
+
+        We however keep a months worth of highlighted notifications, so that
+        users can still get a list of recent highlights.
+
+        Args:
+            txn: The transcation
+            room_id: Room ID to delete from
+            user_id: user ID to delete for
+            stream_ordering: The lowest stream ordering which will
+                                  not be deleted.
+        """
+        txn.call_after(
+            self.get_unread_event_push_actions_by_room_for_user.invalidate_many,
+            (room_id, user_id),
+        )
+
+        # We need to join on the events table to get the received_ts for
+        # event_push_actions and sqlite won't let us use a join in a delete so
+        # we can't just delete where received_ts < x. Furthermore we can
+        # only identify event_push_actions by a tuple of room_id, event_id
+        # we we can't use a subquery.
+        # Instead, we look up the stream ordering for the last event in that
+        # room received before the threshold time and delete event_push_actions
+        # in the room with a stream_odering before that.
+        txn.execute(
+            "DELETE FROM event_push_actions "
+            " WHERE user_id = ? AND room_id = ? AND "
+            " stream_ordering <= ?"
+            " AND ((stream_ordering < ? AND highlight = 1) or highlight = 0)",
+            (user_id, room_id, stream_ordering, self.stream_ordering_month_ago),
+        )
+
+        txn.execute(
+            """
+            DELETE FROM event_push_summary
+            WHERE room_id = ? AND user_id = ? AND stream_ordering <= ?
+        """,
+            (room_id, user_id, stream_ordering),
+        )
+
+
 def _action_has_highlight(actions):
     for action in actions:
         try:
diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index f766e148a0..90fb1a1f00 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -34,7 +34,7 @@ from synapse.storage.database import DatabasePool, LoggingTransaction
 from synapse.storage.databases.main.search import SearchEntry
 from synapse.storage.util.id_generators import MultiWriterIdGenerator
 from synapse.types import StateMap, get_domain_from_id
-from synapse.util.frozenutils import frozendict_json_encoder
+from synapse.util import json_encoder
 from synapse.util.iterutils import batch_iter
 
 if TYPE_CHECKING:
@@ -52,16 +52,6 @@ event_counter = Counter(
 )
 
 
-def encode_json(json_object):
-    """
-    Encode a Python object as JSON and return it in a Unicode string.
-    """
-    out = frozendict_json_encoder.encode(json_object)
-    if isinstance(out, bytes):
-        out = out.decode("utf8")
-    return out
-
-
 _EventCacheEntry = namedtuple("_EventCacheEntry", ("event", "redacted_event"))
 
 
@@ -341,6 +331,10 @@ class PersistEventsStore:
         min_stream_order = events_and_contexts[0][0].internal_metadata.stream_ordering
         max_stream_order = events_and_contexts[-1][0].internal_metadata.stream_ordering
 
+        # stream orderings should have been assigned by now
+        assert min_stream_order
+        assert max_stream_order
+
         self._update_forward_extremities_txn(
             txn,
             new_forward_extremities=new_forward_extremeties,
@@ -367,6 +361,8 @@ class PersistEventsStore:
 
         self._store_event_txn(txn, events_and_contexts=events_and_contexts)
 
+        self._persist_transaction_ids_txn(txn, events_and_contexts)
+
         # Insert into event_to_state_groups.
         self._store_event_state_mappings_txn(txn, events_and_contexts)
 
@@ -411,6 +407,35 @@ class PersistEventsStore:
         # room_memberships, where applicable.
         self._update_current_state_txn(txn, state_delta_for_room, min_stream_order)
 
+    def _persist_transaction_ids_txn(
+        self,
+        txn: LoggingTransaction,
+        events_and_contexts: List[Tuple[EventBase, EventContext]],
+    ):
+        """Persist the mapping from transaction IDs to event IDs (if defined).
+        """
+
+        to_insert = []
+        for event, _ in events_and_contexts:
+            token_id = getattr(event.internal_metadata, "token_id", None)
+            txn_id = getattr(event.internal_metadata, "txn_id", None)
+            if token_id and txn_id:
+                to_insert.append(
+                    {
+                        "event_id": event.event_id,
+                        "room_id": event.room_id,
+                        "user_id": event.sender,
+                        "token_id": token_id,
+                        "txn_id": txn_id,
+                        "inserted_ts": self._clock.time_msec(),
+                    }
+                )
+
+        if to_insert:
+            self.db_pool.simple_insert_many_txn(
+                txn, table="event_txn_id", values=to_insert,
+            )
+
     def _update_current_state_txn(
         self,
         txn: LoggingTransaction,
@@ -432,12 +457,12 @@ class PersistEventsStore:
                 # so that async background tasks get told what happened.
                 sql = """
                     INSERT INTO current_state_delta_stream
-                        (stream_id, room_id, type, state_key, event_id, prev_event_id)
-                    SELECT ?, room_id, type, state_key, null, event_id
+                        (stream_id, instance_name, room_id, type, state_key, event_id, prev_event_id)
+                    SELECT ?, ?, room_id, type, state_key, null, event_id
                         FROM current_state_events
                         WHERE room_id = ?
                 """
-                txn.execute(sql, (stream_id, room_id))
+                txn.execute(sql, (stream_id, self._instance_name, room_id))
 
                 self.db_pool.simple_delete_txn(
                     txn, table="current_state_events", keyvalues={"room_id": room_id},
@@ -458,8 +483,8 @@ class PersistEventsStore:
                 #
                 sql = """
                     INSERT INTO current_state_delta_stream
-                    (stream_id, room_id, type, state_key, event_id, prev_event_id)
-                    SELECT ?, ?, ?, ?, ?, (
+                    (stream_id, instance_name, room_id, type, state_key, event_id, prev_event_id)
+                    SELECT ?, ?, ?, ?, ?, ?, (
                         SELECT event_id FROM current_state_events
                         WHERE room_id = ? AND type = ? AND state_key = ?
                     )
@@ -469,6 +494,7 @@ class PersistEventsStore:
                     (
                         (
                             stream_id,
+                            self._instance_name,
                             room_id,
                             etype,
                             state_key,
@@ -743,7 +769,7 @@ class PersistEventsStore:
                     logger.exception("")
                     raise
 
-                metadata_json = encode_json(event.internal_metadata.get_dict())
+                metadata_json = json_encoder.encode(event.internal_metadata.get_dict())
 
                 sql = "UPDATE event_json SET internal_metadata = ? WHERE event_id = ?"
                 txn.execute(sql, (metadata_json, event.event_id))
@@ -759,6 +785,7 @@ class PersistEventsStore:
                         "event_stream_ordering": stream_order,
                         "event_id": event.event_id,
                         "state_group": state_group_id,
+                        "instance_name": self._instance_name,
                     },
                 )
 
@@ -797,10 +824,10 @@ class PersistEventsStore:
                 {
                     "event_id": event.event_id,
                     "room_id": event.room_id,
-                    "internal_metadata": encode_json(
+                    "internal_metadata": json_encoder.encode(
                         event.internal_metadata.get_dict()
                     ),
-                    "json": encode_json(event_dict(event)),
+                    "json": json_encoder.encode(event_dict(event)),
                     "format_version": event.format_version,
                 }
                 for event, _ in events_and_contexts
@@ -1022,9 +1049,7 @@ class PersistEventsStore:
 
         def prefill():
             for cache_entry in to_prefill:
-                self.store._get_event_cache.prefill(
-                    (cache_entry[0].event_id,), cache_entry
-                )
+                self.store._get_event_cache.set((cache_entry[0].event_id,), cache_entry)
 
         txn.call_after(prefill)
 
diff --git a/synapse/storage/databases/main/events_bg_updates.py b/synapse/storage/databases/main/events_bg_updates.py
index 5e4af2eb51..97b6754846 100644
--- a/synapse/storage/databases/main/events_bg_updates.py
+++ b/synapse/storage/databases/main/events_bg_updates.py
@@ -92,6 +92,13 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
             where_clause="NOT have_censored",
         )
 
+        self.db_pool.updates.register_background_index_update(
+            "users_have_local_media",
+            index_name="users_have_local_media",
+            table="local_media_repository",
+            columns=["user_id", "created_ts"],
+        )
+
     async def _background_reindex_fields_sender(self, progress, batch_size):
         target_min_stream_id = progress["target_min_stream_id_inclusive"]
         max_stream_id = progress["max_stream_id_exclusive"]
diff --git a/synapse/storage/databases/main/events_worker.py b/synapse/storage/databases/main/events_worker.py
index f95679ebc4..4732685f6e 100644
--- a/synapse/storage/databases/main/events_worker.py
+++ b/synapse/storage/databases/main/events_worker.py
@@ -12,7 +12,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import itertools
 import logging
 import threading
@@ -32,9 +31,13 @@ from synapse.api.room_versions import (
     RoomVersions,
 )
 from synapse.events import EventBase, make_event_from_dict
+from synapse.events.snapshot import EventContext
 from synapse.events.utils import prune_event
 from synapse.logging.context import PreserveLoggingContext, current_context
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import (
+    run_as_background_process,
+    wrap_as_background_process,
+)
 from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
 from synapse.replication.tcp.streams import BackfillStream
 from synapse.replication.tcp.streams.events import EventsStream
@@ -42,8 +45,9 @@ from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_cla
 from synapse.storage.database import DatabasePool
 from synapse.storage.engines import PostgresEngine
 from synapse.storage.util.id_generators import MultiWriterIdGenerator, StreamIdGenerator
-from synapse.types import Collection, get_domain_from_id
-from synapse.util.caches.descriptors import Cache, cached
+from synapse.types import Collection, JsonDict, get_domain_from_id
+from synapse.util.caches.descriptors import cached
+from synapse.util.caches.lrucache import LruCache
 from synapse.util.iterutils import batch_iter
 from synapse.util.metrics import Measure
 
@@ -74,6 +78,13 @@ class EventRedactBehaviour(Names):
 
 
 class EventsWorkerStore(SQLBaseStore):
+    # Whether to use dedicated DB threads for event fetching. This is only used
+    # if there are multiple DB threads available. When used will lock the DB
+    # thread for periods of time (so unit tests want to disable this when they
+    # run DB transactions on the main thread). See EVENT_QUEUE_* for more
+    # options controlling this.
+    USE_DEDICATED_DB_THREADS_FOR_EVENT_FETCHING = True
+
     def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
 
@@ -130,11 +141,16 @@ class EventsWorkerStore(SQLBaseStore):
                     db_conn, "events", "stream_ordering", step=-1
                 )
 
-        self._get_event_cache = Cache(
-            "*getEvent*",
+        if hs.config.run_background_tasks:
+            # We periodically clean out old transaction ID mappings
+            self._clock.looping_call(
+                self._cleanup_old_transaction_ids, 5 * 60 * 1000,
+            )
+
+        self._get_event_cache = LruCache(
+            cache_name="*getEvent*",
             keylen=3,
-            max_entries=hs.config.caches.event_cache_size,
-            apply_cache_factor_from_config=False,
+            max_size=hs.config.caches.event_cache_size,
         )
 
         self._event_fetch_lock = threading.Condition()
@@ -510,6 +526,57 @@ class EventsWorkerStore(SQLBaseStore):
 
         return event_map
 
+    async def get_stripped_room_state_from_event_context(
+        self,
+        context: EventContext,
+        state_types_to_include: List[EventTypes],
+        membership_user_id: Optional[str] = None,
+    ) -> List[JsonDict]:
+        """
+        Retrieve the stripped state from a room, given an event context to retrieve state
+        from as well as the state types to include. Optionally, include the membership
+        events from a specific user.
+
+        "Stripped" state means that only the `type`, `state_key`, `content` and `sender` keys
+        are included from each state event.
+
+        Args:
+            context: The event context to retrieve state of the room from.
+            state_types_to_include: The type of state events to include.
+            membership_user_id: An optional user ID to include the stripped membership state
+                events of. This is useful when generating the stripped state of a room for
+                invites. We want to send membership events of the inviter, so that the
+                invitee can display the inviter's profile information if the room lacks any.
+
+        Returns:
+            A list of dictionaries, each representing a stripped state event from the room.
+        """
+        current_state_ids = await context.get_current_state_ids()
+
+        # We know this event is not an outlier, so this must be
+        # non-None.
+        assert current_state_ids is not None
+
+        # The state to include
+        state_to_include_ids = [
+            e_id
+            for k, e_id in current_state_ids.items()
+            if k[0] in state_types_to_include
+            or (membership_user_id and k == (EventTypes.Member, membership_user_id))
+        ]
+
+        state_to_include = await self.get_events(state_to_include_ids)
+
+        return [
+            {
+                "type": e.type,
+                "state_key": e.state_key,
+                "content": e.content,
+                "sender": e.sender,
+            }
+            for e in state_to_include.values()
+        ]
+
     def _do_fetch(self, conn):
         """Takes a database connection and waits for requests for events from
         the _event_fetch_list queue.
@@ -522,7 +589,11 @@ class EventsWorkerStore(SQLBaseStore):
 
                 if not event_list:
                     single_threaded = self.database_engine.single_threaded
-                    if single_threaded or i > EVENT_QUEUE_ITERATIONS:
+                    if (
+                        not self.USE_DEDICATED_DB_THREADS_FOR_EVENT_FETCHING
+                        or single_threaded
+                        or i > EVENT_QUEUE_ITERATIONS
+                    ):
                         self._event_fetch_ongoing -= 1
                         return
                     else:
@@ -712,6 +783,7 @@ class EventsWorkerStore(SQLBaseStore):
                 internal_metadata_dict=internal_metadata,
                 rejected_reason=rejected_reason,
             )
+            original_ev.internal_metadata.stream_ordering = row["stream_ordering"]
 
             event_map[event_id] = original_ev
 
@@ -728,7 +800,7 @@ class EventsWorkerStore(SQLBaseStore):
                 event=original_ev, redacted_event=redacted_event
             )
 
-            self._get_event_cache.prefill((event_id,), cache_entry)
+            self._get_event_cache.set((event_id,), cache_entry)
             result_map[event_id] = cache_entry
 
         return result_map
@@ -779,6 +851,8 @@ class EventsWorkerStore(SQLBaseStore):
 
          * event_id (str)
 
+         * stream_ordering (int): stream ordering for this event
+
          * json (str): json-encoded event structure
 
          * internal_metadata (str): json-encoded internal metadata dict
@@ -811,13 +885,15 @@ class EventsWorkerStore(SQLBaseStore):
             sql = """\
                 SELECT
                   e.event_id,
-                  e.internal_metadata,
-                  e.json,
-                  e.format_version,
+                  e.stream_ordering,
+                  ej.internal_metadata,
+                  ej.json,
+                  ej.format_version,
                   r.room_version,
                   rej.reason
-                FROM event_json as e
-                  LEFT JOIN rooms r USING (room_id)
+                FROM events AS e
+                  JOIN event_json AS ej USING (event_id)
+                  LEFT JOIN rooms r ON r.room_id = e.room_id
                   LEFT JOIN rejections as rej USING (event_id)
                 WHERE """
 
@@ -831,11 +907,12 @@ class EventsWorkerStore(SQLBaseStore):
                 event_id = row[0]
                 event_dict[event_id] = {
                     "event_id": event_id,
-                    "internal_metadata": row[1],
-                    "json": row[2],
-                    "format_version": row[3],
-                    "room_version_id": row[4],
-                    "rejected_reason": row[5],
+                    "stream_ordering": row[1],
+                    "internal_metadata": row[2],
+                    "json": row[3],
+                    "format_version": row[4],
+                    "room_version_id": row[5],
+                    "rejected_reason": row[6],
                     "redactions": [],
                 }
 
@@ -1017,16 +1094,12 @@ class EventsWorkerStore(SQLBaseStore):
 
         return {"v1": complexity_v1}
 
-    def get_current_backfill_token(self):
-        """The current minimum token that backfilled events have reached"""
-        return -self._backfill_id_gen.get_current_token()
-
     def get_current_events_token(self):
         """The current maximum token that events have reached"""
         return self._stream_id_gen.get_current_token()
 
     async def get_all_new_forward_event_rows(
-        self, last_id: int, current_id: int, limit: int
+        self, instance_name: str, last_id: int, current_id: int, limit: int
     ) -> List[Tuple]:
         """Returns new events, for the Events replication stream
 
@@ -1044,16 +1117,19 @@ class EventsWorkerStore(SQLBaseStore):
         def get_all_new_forward_event_rows(txn):
             sql = (
                 "SELECT e.stream_ordering, e.event_id, e.room_id, e.type,"
-                " state_key, redacts, relates_to_id"
+                " state_key, redacts, relates_to_id, membership, rejections.reason IS NOT NULL"
                 " FROM events AS e"
                 " LEFT JOIN redactions USING (event_id)"
                 " LEFT JOIN state_events USING (event_id)"
                 " LEFT JOIN event_relations USING (event_id)"
+                " LEFT JOIN room_memberships USING (event_id)"
+                " LEFT JOIN rejections USING (event_id)"
                 " WHERE ? < stream_ordering AND stream_ordering <= ?"
+                " AND instance_name = ?"
                 " ORDER BY stream_ordering ASC"
                 " LIMIT ?"
             )
-            txn.execute(sql, (last_id, current_id, limit))
+            txn.execute(sql, (last_id, current_id, instance_name, limit))
             return txn.fetchall()
 
         return await self.db_pool.runInteraction(
@@ -1061,7 +1137,7 @@ class EventsWorkerStore(SQLBaseStore):
         )
 
     async def get_ex_outlier_stream_rows(
-        self, last_id: int, current_id: int
+        self, instance_name: str, last_id: int, current_id: int
     ) -> List[Tuple]:
         """Returns de-outliered events, for the Events replication stream
 
@@ -1078,18 +1154,21 @@ class EventsWorkerStore(SQLBaseStore):
         def get_ex_outlier_stream_rows_txn(txn):
             sql = (
                 "SELECT event_stream_ordering, e.event_id, e.room_id, e.type,"
-                " state_key, redacts, relates_to_id"
+                " state_key, redacts, relates_to_id, membership, rejections.reason IS NOT NULL"
                 " FROM events AS e"
-                " INNER JOIN ex_outlier_stream USING (event_id)"
+                " INNER JOIN ex_outlier_stream AS out USING (event_id)"
                 " LEFT JOIN redactions USING (event_id)"
                 " LEFT JOIN state_events USING (event_id)"
                 " LEFT JOIN event_relations USING (event_id)"
+                " LEFT JOIN room_memberships USING (event_id)"
+                " LEFT JOIN rejections USING (event_id)"
                 " WHERE ? < event_stream_ordering"
                 " AND event_stream_ordering <= ?"
+                " AND out.instance_name = ?"
                 " ORDER BY event_stream_ordering ASC"
             )
 
-            txn.execute(sql, (last_id, current_id))
+            txn.execute(sql, (last_id, current_id, instance_name))
             return txn.fetchall()
 
         return await self.db_pool.runInteraction(
@@ -1102,6 +1181,9 @@ class EventsWorkerStore(SQLBaseStore):
         """Get updates for backfill replication stream, including all new
         backfilled events and events that have gone from being outliers to not.
 
+        NOTE: The IDs given here are from replication, and so should be
+        *positive*.
+
         Args:
             instance_name: The writer we want to fetch updates from. Unused
                 here since there is only ever one writer.
@@ -1132,10 +1214,11 @@ class EventsWorkerStore(SQLBaseStore):
                 " LEFT JOIN state_events USING (event_id)"
                 " LEFT JOIN event_relations USING (event_id)"
                 " WHERE ? > stream_ordering AND stream_ordering >= ?"
+                "  AND instance_name = ?"
                 " ORDER BY stream_ordering ASC"
                 " LIMIT ?"
             )
-            txn.execute(sql, (-last_id, -current_id, limit))
+            txn.execute(sql, (-last_id, -current_id, instance_name, limit))
             new_event_updates = [(row[0], row[1:]) for row in txn]
 
             limited = False
@@ -1149,15 +1232,16 @@ class EventsWorkerStore(SQLBaseStore):
                 "SELECT -event_stream_ordering, e.event_id, e.room_id, e.type,"
                 " state_key, redacts, relates_to_id"
                 " FROM events AS e"
-                " INNER JOIN ex_outlier_stream USING (event_id)"
+                " INNER JOIN ex_outlier_stream AS out USING (event_id)"
                 " LEFT JOIN redactions USING (event_id)"
                 " LEFT JOIN state_events USING (event_id)"
                 " LEFT JOIN event_relations USING (event_id)"
                 " WHERE ? > event_stream_ordering"
                 " AND event_stream_ordering >= ?"
+                " AND out.instance_name = ?"
                 " ORDER BY event_stream_ordering DESC"
             )
-            txn.execute(sql, (-last_id, -upper_bound))
+            txn.execute(sql, (-last_id, -upper_bound, instance_name))
             new_event_updates.extend((row[0], row[1:]) for row in txn)
 
             if len(new_event_updates) >= limit:
@@ -1171,7 +1255,7 @@ class EventsWorkerStore(SQLBaseStore):
         )
 
     async def get_all_updated_current_state_deltas(
-        self, from_token: int, to_token: int, target_row_count: int
+        self, instance_name: str, from_token: int, to_token: int, target_row_count: int
     ) -> Tuple[List[Tuple], int, bool]:
         """Fetch updates from current_state_delta_stream
 
@@ -1197,9 +1281,10 @@ class EventsWorkerStore(SQLBaseStore):
                 SELECT stream_id, room_id, type, state_key, event_id
                 FROM current_state_delta_stream
                 WHERE ? < stream_id AND stream_id <= ?
+                    AND instance_name = ?
                 ORDER BY stream_id ASC LIMIT ?
             """
-            txn.execute(sql, (from_token, to_token, target_row_count))
+            txn.execute(sql, (from_token, to_token, instance_name, target_row_count))
             return txn.fetchall()
 
         def get_deltas_for_stream_id_txn(txn, stream_id):
@@ -1287,3 +1372,77 @@ class EventsWorkerStore(SQLBaseStore):
         return await self.db_pool.runInteraction(
             desc="get_next_event_to_expire", func=get_next_event_to_expire_txn
         )
+
+    async def get_event_id_from_transaction_id(
+        self, room_id: str, user_id: str, token_id: int, txn_id: str
+    ) -> Optional[str]:
+        """Look up if we have already persisted an event for the transaction ID,
+        returning the event ID if so.
+        """
+        return await self.db_pool.simple_select_one_onecol(
+            table="event_txn_id",
+            keyvalues={
+                "room_id": room_id,
+                "user_id": user_id,
+                "token_id": token_id,
+                "txn_id": txn_id,
+            },
+            retcol="event_id",
+            allow_none=True,
+            desc="get_event_id_from_transaction_id",
+        )
+
+    async def get_already_persisted_events(
+        self, events: Iterable[EventBase]
+    ) -> Dict[str, str]:
+        """Look up if we have already persisted an event for the transaction ID,
+        returning a mapping from event ID in the given list to the event ID of
+        an existing event.
+
+        Also checks if there are duplicates in the given events, if there are
+        will map duplicates to the *first* event.
+        """
+
+        mapping = {}
+        txn_id_to_event = {}  # type: Dict[Tuple[str, int, str], str]
+
+        for event in events:
+            token_id = getattr(event.internal_metadata, "token_id", None)
+            txn_id = getattr(event.internal_metadata, "txn_id", None)
+
+            if token_id and txn_id:
+                # Check if this is a duplicate of an event in the given events.
+                existing = txn_id_to_event.get((event.room_id, token_id, txn_id))
+                if existing:
+                    mapping[event.event_id] = existing
+                    continue
+
+                # Check if this is a duplicate of an event we've already
+                # persisted.
+                existing = await self.get_event_id_from_transaction_id(
+                    event.room_id, event.sender, token_id, txn_id
+                )
+                if existing:
+                    mapping[event.event_id] = existing
+                    txn_id_to_event[(event.room_id, token_id, txn_id)] = existing
+                else:
+                    txn_id_to_event[(event.room_id, token_id, txn_id)] = event.event_id
+
+        return mapping
+
+    @wrap_as_background_process("_cleanup_old_transaction_ids")
+    async def _cleanup_old_transaction_ids(self):
+        """Cleans out transaction id mappings older than 24hrs.
+        """
+
+        def _cleanup_old_transaction_ids_txn(txn):
+            sql = """
+                DELETE FROM event_txn_id
+                WHERE inserted_ts < ?
+            """
+            one_day_ago = self._clock.time_msec() - 24 * 60 * 60 * 1000
+            txn.execute(sql, (one_day_ago,))
+
+        return await self.db_pool.runInteraction(
+            "_cleanup_old_transaction_ids", _cleanup_old_transaction_ids_txn,
+        )
diff --git a/synapse/storage/databases/main/keys.py b/synapse/storage/databases/main/keys.py
index ad43bb05ab..f8f4bb9b3f 100644
--- a/synapse/storage/databases/main/keys.py
+++ b/synapse/storage/databases/main/keys.py
@@ -122,9 +122,7 @@ class KeyStore(SQLBaseStore):
             # param, which is itself the 2-tuple (server_name, key_id).
             invalidations.append((server_name, key_id))
 
-        await self.db_pool.runInteraction(
-            "store_server_verify_keys",
-            self.db_pool.simple_upsert_many_txn,
+        await self.db_pool.simple_upsert_many(
             table="server_signature_keys",
             key_names=("server_name", "key_id"),
             key_values=key_values,
@@ -135,6 +133,7 @@ class KeyStore(SQLBaseStore):
                 "verify_key",
             ),
             value_values=value_values,
+            desc="store_server_verify_keys",
         )
 
         invalidate = self._get_server_verify_key.invalidate
diff --git a/synapse/storage/databases/main/media_repository.py b/synapse/storage/databases/main/media_repository.py
index cc538c5c10..4b2f224718 100644
--- a/synapse/storage/databases/main/media_repository.py
+++ b/synapse/storage/databases/main/media_repository.py
@@ -93,6 +93,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
 
     def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
+        self.server_name = hs.hostname
 
     async def get_local_media(self, media_id: str) -> Optional[Dict[str, Any]]:
         """Get the metadata for a local piece of media
@@ -115,6 +116,109 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
             desc="get_local_media",
         )
 
+    async def get_local_media_by_user_paginate(
+        self, start: int, limit: int, user_id: str
+    ) -> Tuple[List[Dict[str, Any]], int]:
+        """Get a paginated list of metadata for a local piece of media
+        which an user_id has uploaded
+
+        Args:
+            start: offset in the list
+            limit: maximum amount of media_ids to retrieve
+            user_id: fully-qualified user id
+        Returns:
+            A paginated list of all metadata of user's media,
+            plus the total count of all the user's media
+        """
+
+        def get_local_media_by_user_paginate_txn(txn):
+
+            args = [user_id]
+            sql = """
+                SELECT COUNT(*) as total_media
+                FROM local_media_repository
+                WHERE user_id = ?
+            """
+            txn.execute(sql, args)
+            count = txn.fetchone()[0]
+
+            sql = """
+                SELECT
+                    "media_id",
+                    "media_type",
+                    "media_length",
+                    "upload_name",
+                    "created_ts",
+                    "last_access_ts",
+                    "quarantined_by",
+                    "safe_from_quarantine"
+                FROM local_media_repository
+                WHERE user_id = ?
+                ORDER BY created_ts DESC, media_id DESC
+                LIMIT ? OFFSET ?
+            """
+
+            args += [limit, start]
+            txn.execute(sql, args)
+            media = self.db_pool.cursor_to_dict(txn)
+            return media, count
+
+        return await self.db_pool.runInteraction(
+            "get_local_media_by_user_paginate_txn", get_local_media_by_user_paginate_txn
+        )
+
+    async def get_local_media_before(
+        self, before_ts: int, size_gt: int, keep_profiles: bool,
+    ) -> Optional[List[str]]:
+
+        # to find files that have never been accessed (last_access_ts IS NULL)
+        # compare with `created_ts`
+        sql = """
+            SELECT media_id
+            FROM local_media_repository AS lmr
+            WHERE
+                ( last_access_ts < ?
+                OR ( created_ts < ? AND last_access_ts IS NULL ) )
+                AND media_length > ?
+        """
+
+        if keep_profiles:
+            sql_keep = """
+                AND (
+                    NOT EXISTS
+                        (SELECT 1
+                         FROM profiles
+                         WHERE profiles.avatar_url = '{media_prefix}' || lmr.media_id)
+                    AND NOT EXISTS
+                        (SELECT 1
+                         FROM groups
+                         WHERE groups.avatar_url = '{media_prefix}' || lmr.media_id)
+                    AND NOT EXISTS
+                        (SELECT 1
+                         FROM room_memberships
+                         WHERE room_memberships.avatar_url = '{media_prefix}' || lmr.media_id)
+                    AND NOT EXISTS
+                        (SELECT 1
+                         FROM user_directory
+                         WHERE user_directory.avatar_url = '{media_prefix}' || lmr.media_id)
+                    AND NOT EXISTS
+                        (SELECT 1
+                         FROM room_stats_state
+                         WHERE room_stats_state.avatar = '{media_prefix}' || lmr.media_id)
+                )
+            """.format(
+                media_prefix="mxc://%s/" % (self.server_name,),
+            )
+            sql += sql_keep
+
+        def _get_local_media_before_txn(txn):
+            txn.execute(sql, (before_ts, before_ts, size_gt))
+            return [row[0] for row in txn]
+
+        return await self.db_pool.runInteraction(
+            "get_local_media_before", _get_local_media_before_txn
+        )
+
     async def store_local_media(
         self,
         media_id,
@@ -348,6 +452,33 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
             desc="get_remote_media_thumbnails",
         )
 
+    async def get_remote_media_thumbnail(
+        self, origin: str, media_id: str, t_width: int, t_height: int, t_type: str,
+    ) -> Optional[Dict[str, Any]]:
+        """Fetch the thumbnail info of given width, height and type.
+        """
+
+        return await self.db_pool.simple_select_one(
+            table="remote_media_cache_thumbnails",
+            keyvalues={
+                "media_origin": origin,
+                "media_id": media_id,
+                "thumbnail_width": t_width,
+                "thumbnail_height": t_height,
+                "thumbnail_type": t_type,
+            },
+            retcols=(
+                "thumbnail_width",
+                "thumbnail_height",
+                "thumbnail_method",
+                "thumbnail_type",
+                "thumbnail_length",
+                "filesystem_id",
+            ),
+            allow_none=True,
+            desc="get_remote_media_thumbnail",
+        )
+
     async def store_remote_media_thumbnail(
         self,
         origin,
diff --git a/synapse/storage/databases/main/metrics.py b/synapse/storage/databases/main/metrics.py
index 92099f95ce..ab18cc4d79 100644
--- a/synapse/storage/databases/main/metrics.py
+++ b/synapse/storage/databases/main/metrics.py
@@ -12,15 +12,21 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import calendar
+import logging
+import time
+from typing import Dict
 
 from synapse.metrics import GaugeBucketCollector
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.database import DatabasePool
 from synapse.storage.databases.main.event_push_actions import (
     EventPushActionsWorkerStore,
 )
 
+logger = logging.getLogger(__name__)
+
 # Collect metrics on the number of forward extremities that exist.
 _extremities_collecter = GaugeBucketCollector(
     "synapse_forward_extremities",
@@ -51,15 +57,13 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
         super().__init__(database, db_conn, hs)
 
         # Read the extrems every 60 minutes
-        def read_forward_extremities():
-            # run as a background process to make sure that the database transactions
-            # have a logcontext to report to
-            return run_as_background_process(
-                "read_forward_extremities", self._read_forward_extremities
-            )
+        if hs.config.run_background_tasks:
+            self._clock.looping_call(self._read_forward_extremities, 60 * 60 * 1000)
 
-        hs.get_clock().looping_call(read_forward_extremities, 60 * 60 * 1000)
+        # Used in _generate_user_daily_visits to keep track of progress
+        self._last_user_visit_update = self._get_start_of_day()
 
+    @wrap_as_background_process("read_forward_extremities")
     async def _read_forward_extremities(self):
         def fetch(txn):
             txn.execute(
@@ -137,3 +141,196 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             return count
 
         return await self.db_pool.runInteraction("count_daily_active_rooms", _count)
+
+    async def count_daily_users(self) -> int:
+        """
+        Counts the number of users who used this homeserver in the last 24 hours.
+        """
+        yesterday = int(self._clock.time_msec()) - (1000 * 60 * 60 * 24)
+        return await self.db_pool.runInteraction(
+            "count_daily_users", self._count_users, yesterday
+        )
+
+    async def count_monthly_users(self) -> int:
+        """
+        Counts the number of users who used this homeserver in the last 30 days.
+        Note this method is intended for phonehome metrics only and is different
+        from the mau figure in synapse.storage.monthly_active_users which,
+        amongst other things, includes a 3 day grace period before a user counts.
+        """
+        thirty_days_ago = int(self._clock.time_msec()) - (1000 * 60 * 60 * 24 * 30)
+        return await self.db_pool.runInteraction(
+            "count_monthly_users", self._count_users, thirty_days_ago
+        )
+
+    def _count_users(self, txn, time_from):
+        """
+        Returns number of users seen in the past time_from period
+        """
+        sql = """
+            SELECT COALESCE(count(*), 0) FROM (
+                SELECT user_id FROM user_ips
+                WHERE last_seen > ?
+                GROUP BY user_id
+            ) u
+        """
+        txn.execute(sql, (time_from,))
+        (count,) = txn.fetchone()
+        return count
+
+    async def count_r30_users(self) -> Dict[str, int]:
+        """
+        Counts the number of 30 day retained users, defined as:-
+         * Users who have created their accounts more than 30 days ago
+         * Where last seen at most 30 days ago
+         * Where account creation and last_seen are > 30 days apart
+
+        Returns:
+             A mapping of counts globally as well as broken out by platform.
+        """
+
+        def _count_r30_users(txn):
+            thirty_days_in_secs = 86400 * 30
+            now = int(self._clock.time())
+            thirty_days_ago_in_secs = now - thirty_days_in_secs
+
+            sql = """
+                SELECT platform, COALESCE(count(*), 0) FROM (
+                     SELECT
+                        users.name, platform, users.creation_ts * 1000,
+                        MAX(uip.last_seen)
+                     FROM users
+                     INNER JOIN (
+                         SELECT
+                         user_id,
+                         last_seen,
+                         CASE
+                             WHEN user_agent LIKE '%%Android%%' THEN 'android'
+                             WHEN user_agent LIKE '%%iOS%%' THEN 'ios'
+                             WHEN user_agent LIKE '%%Electron%%' THEN 'electron'
+                             WHEN user_agent LIKE '%%Mozilla%%' THEN 'web'
+                             WHEN user_agent LIKE '%%Gecko%%' THEN 'web'
+                             ELSE 'unknown'
+                         END
+                         AS platform
+                         FROM user_ips
+                     ) uip
+                     ON users.name = uip.user_id
+                     AND users.appservice_id is NULL
+                     AND users.creation_ts < ?
+                     AND uip.last_seen/1000 > ?
+                     AND (uip.last_seen/1000) - users.creation_ts > 86400 * 30
+                     GROUP BY users.name, platform, users.creation_ts
+                ) u GROUP BY platform
+            """
+
+            results = {}
+            txn.execute(sql, (thirty_days_ago_in_secs, thirty_days_ago_in_secs))
+
+            for row in txn:
+                if row[0] == "unknown":
+                    pass
+                results[row[0]] = row[1]
+
+            sql = """
+                SELECT COALESCE(count(*), 0) FROM (
+                    SELECT users.name, users.creation_ts * 1000,
+                                                        MAX(uip.last_seen)
+                    FROM users
+                    INNER JOIN (
+                        SELECT
+                        user_id,
+                        last_seen
+                        FROM user_ips
+                    ) uip
+                    ON users.name = uip.user_id
+                    AND appservice_id is NULL
+                    AND users.creation_ts < ?
+                    AND uip.last_seen/1000 > ?
+                    AND (uip.last_seen/1000) - users.creation_ts > 86400 * 30
+                    GROUP BY users.name, users.creation_ts
+                ) u
+            """
+
+            txn.execute(sql, (thirty_days_ago_in_secs, thirty_days_ago_in_secs))
+
+            (count,) = txn.fetchone()
+            results["all"] = count
+
+            return results
+
+        return await self.db_pool.runInteraction("count_r30_users", _count_r30_users)
+
+    def _get_start_of_day(self):
+        """
+        Returns millisecond unixtime for start of UTC day.
+        """
+        now = time.gmtime()
+        today_start = calendar.timegm((now.tm_year, now.tm_mon, now.tm_mday, 0, 0, 0))
+        return today_start * 1000
+
+    @wrap_as_background_process("generate_user_daily_visits")
+    async def generate_user_daily_visits(self) -> None:
+        """
+        Generates daily visit data for use in cohort/ retention analysis
+        """
+
+        def _generate_user_daily_visits(txn):
+            logger.info("Calling _generate_user_daily_visits")
+            today_start = self._get_start_of_day()
+            a_day_in_milliseconds = 24 * 60 * 60 * 1000
+            now = self._clock.time_msec()
+
+            # A note on user_agent. Technically a given device can have multiple
+            # user agents, so we need to decide which one to pick. We could have
+            # handled this in number of ways, but given that we don't care
+            # _that_ much we have gone for MAX(). For more details of the other
+            # options considered see
+            # https://github.com/matrix-org/synapse/pull/8503#discussion_r502306111
+            sql = """
+                INSERT INTO user_daily_visits (user_id, device_id, timestamp, user_agent)
+                    SELECT u.user_id, u.device_id, ?, MAX(u.user_agent)
+                    FROM user_ips AS u
+                    LEFT JOIN (
+                      SELECT user_id, device_id, timestamp FROM user_daily_visits
+                      WHERE timestamp = ?
+                    ) udv
+                    ON u.user_id = udv.user_id AND u.device_id=udv.device_id
+                    INNER JOIN users ON users.name=u.user_id
+                    WHERE last_seen > ? AND last_seen <= ?
+                    AND udv.timestamp IS NULL AND users.is_guest=0
+                    AND users.appservice_id IS NULL
+                    GROUP BY u.user_id, u.device_id
+            """
+
+            # This means that the day has rolled over but there could still
+            # be entries from the previous day. There is an edge case
+            # where if the user logs in at 23:59 and overwrites their
+            # last_seen at 00:01 then they will not be counted in the
+            # previous day's stats - it is important that the query is run
+            # often to minimise this case.
+            if today_start > self._last_user_visit_update:
+                yesterday_start = today_start - a_day_in_milliseconds
+                txn.execute(
+                    sql,
+                    (
+                        yesterday_start,
+                        yesterday_start,
+                        self._last_user_visit_update,
+                        today_start,
+                    ),
+                )
+                self._last_user_visit_update = today_start
+
+            txn.execute(
+                sql, (today_start, today_start, self._last_user_visit_update, now)
+            )
+            # Update _last_user_visit_update to now. The reason to do this
+            # rather just clamping to the beginning of the day is to limit
+            # the size of the join - meaning that the query can be run more
+            # frequently
+            self._last_user_visit_update = now
+
+        await self.db_pool.runInteraction(
+            "generate_user_daily_visits", _generate_user_daily_visits
+        )
diff --git a/synapse/storage/databases/main/monthly_active_users.py b/synapse/storage/databases/main/monthly_active_users.py
index e93aad33cd..d788dc0fc6 100644
--- a/synapse/storage/databases/main/monthly_active_users.py
+++ b/synapse/storage/databases/main/monthly_active_users.py
@@ -15,6 +15,7 @@
 import logging
 from typing import Dict, List
 
+from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.database import DatabasePool, make_in_list_sql_clause
 from synapse.util.caches.descriptors import cached
@@ -32,6 +33,9 @@ class MonthlyActiveUsersWorkerStore(SQLBaseStore):
         self._clock = hs.get_clock()
         self.hs = hs
 
+        self._limit_usage_by_mau = hs.config.limit_usage_by_mau
+        self._max_mau_value = hs.config.max_mau_value
+
     @cached(num_args=0)
     async def get_monthly_active_count(self) -> int:
         """Generates current count of monthly active users
@@ -124,60 +128,7 @@ class MonthlyActiveUsersWorkerStore(SQLBaseStore):
             desc="user_last_seen_monthly_active",
         )
 
-
-class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
-    def __init__(self, database: DatabasePool, db_conn, hs):
-        super().__init__(database, db_conn, hs)
-
-        self._limit_usage_by_mau = hs.config.limit_usage_by_mau
-        self._mau_stats_only = hs.config.mau_stats_only
-        self._max_mau_value = hs.config.max_mau_value
-
-        # Do not add more reserved users than the total allowable number
-        # cur = LoggingTransaction(
-        self.db_pool.new_transaction(
-            db_conn,
-            "initialise_mau_threepids",
-            [],
-            [],
-            self._initialise_reserved_users,
-            hs.config.mau_limits_reserved_threepids[: self._max_mau_value],
-        )
-
-    def _initialise_reserved_users(self, txn, threepids):
-        """Ensures that reserved threepids are accounted for in the MAU table, should
-        be called on start up.
-
-        Args:
-            txn (cursor):
-            threepids (list[dict]): List of threepid dicts to reserve
-        """
-
-        # XXX what is this function trying to achieve?  It upserts into
-        # monthly_active_users for each *registered* reserved mau user, but why?
-        #
-        #  - shouldn't there already be an entry for each reserved user (at least
-        #    if they have been active recently)?
-        #
-        #  - if it's important that the timestamp is kept up to date, why do we only
-        #    run this at startup?
-
-        for tp in threepids:
-            user_id = self.get_user_id_by_threepid_txn(txn, tp["medium"], tp["address"])
-
-            if user_id:
-                is_support = self.is_support_user_txn(txn, user_id)
-                if not is_support:
-                    # We do this manually here to avoid hitting #6791
-                    self.db_pool.simple_upsert_txn(
-                        txn,
-                        table="monthly_active_users",
-                        keyvalues={"user_id": user_id},
-                        values={"timestamp": int(self._clock.time_msec())},
-                    )
-            else:
-                logger.warning("mau limit reserved threepid %s not found in db" % tp)
-
+    @wrap_as_background_process("reap_monthly_active_users")
     async def reap_monthly_active_users(self):
         """Cleans out monthly active user table to ensure that no stale
         entries exist.
@@ -257,6 +208,57 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
             "reap_monthly_active_users", _reap_users, reserved_users
         )
 
+
+class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
+    def __init__(self, database: DatabasePool, db_conn, hs):
+        super().__init__(database, db_conn, hs)
+
+        self._mau_stats_only = hs.config.mau_stats_only
+
+        # Do not add more reserved users than the total allowable number
+        self.db_pool.new_transaction(
+            db_conn,
+            "initialise_mau_threepids",
+            [],
+            [],
+            self._initialise_reserved_users,
+            hs.config.mau_limits_reserved_threepids[: self._max_mau_value],
+        )
+
+    def _initialise_reserved_users(self, txn, threepids):
+        """Ensures that reserved threepids are accounted for in the MAU table, should
+        be called on start up.
+
+        Args:
+            txn (cursor):
+            threepids (list[dict]): List of threepid dicts to reserve
+        """
+
+        # XXX what is this function trying to achieve?  It upserts into
+        # monthly_active_users for each *registered* reserved mau user, but why?
+        #
+        #  - shouldn't there already be an entry for each reserved user (at least
+        #    if they have been active recently)?
+        #
+        #  - if it's important that the timestamp is kept up to date, why do we only
+        #    run this at startup?
+
+        for tp in threepids:
+            user_id = self.get_user_id_by_threepid_txn(txn, tp["medium"], tp["address"])
+
+            if user_id:
+                is_support = self.is_support_user_txn(txn, user_id)
+                if not is_support:
+                    # We do this manually here to avoid hitting #6791
+                    self.db_pool.simple_upsert_txn(
+                        txn,
+                        table="monthly_active_users",
+                        keyvalues={"user_id": user_id},
+                        values={"timestamp": int(self._clock.time_msec())},
+                    )
+            else:
+                logger.warning("mau limit reserved threepid %s not found in db" % tp)
+
     async def upsert_monthly_active_user(self, user_id: str) -> None:
         """Updates or inserts the user into the monthly active user table, which
         is used to track the current MAU usage of the server
diff --git a/synapse/storage/databases/main/profile.py b/synapse/storage/databases/main/profile.py
index de37866d25..2570003457 100644
--- a/synapse/storage/databases/main/profile.py
+++ b/synapse/storage/databases/main/profile.py
@@ -45,7 +45,7 @@ class ProfileWorkerStore(SQLBaseStore):
         )
 
     @cached(max_entries=5000)
-    async def get_profile_displayname(self, user_localpart: str) -> str:
+    async def get_profile_displayname(self, user_localpart: str) -> Optional[str]:
         return await self.db_pool.simple_select_one_onecol(
             table="profiles",
             keyvalues={"user_id": user_localpart},
@@ -54,7 +54,7 @@ class ProfileWorkerStore(SQLBaseStore):
         )
 
     @cached(max_entries=5000)
-    async def get_profile_avatar_url(self, user_localpart: str) -> str:
+    async def get_profile_avatar_url(self, user_localpart: str) -> Optional[str]:
         return await self.db_pool.simple_select_one_onecol(
             table="profiles",
             keyvalues={"user_id": user_localpart},
@@ -131,7 +131,7 @@ class ProfileWorkerStore(SQLBaseStore):
         )
 
     async def set_profile_displayname(
-        self, user_localpart: str, new_displayname: str, batchnum: int
+        self, user_localpart: str, new_displayname: Optional[str], batchnum: int
     ) -> None:
         # Invalidate the read cache for this user
         self.get_profile_displayname.invalidate((user_localpart,))
@@ -194,19 +194,6 @@ class ProfileWorkerStore(SQLBaseStore):
             value_values=values,
         )
 
-
-class ProfileStore(ProfileWorkerStore):
-    def __init__(self, database, db_conn, hs):
-        super().__init__(database, db_conn, hs)
-
-        self.db_pool.updates.register_background_index_update(
-            "profile_replication_status_host_index",
-            index_name="profile_replication_status_idx",
-            table="profile_replication_status",
-            columns=["host"],
-            unique=True,
-        )
-
     async def add_remote_profile_cache(
         self, user_id: str, displayname: str, avatar_url: str
     ) -> None:
@@ -252,28 +239,6 @@ class ProfileStore(ProfileWorkerStore):
                 desc="delete_remote_profile_cache",
             )
 
-    async def get_remote_profile_cache_entries_that_expire(
-        self, last_checked: int
-    ) -> Dict[str, str]:
-        """Get all users who haven't been checked since `last_checked`
-        """
-
-        def _get_remote_profile_cache_entries_that_expire_txn(txn):
-            sql = """
-                SELECT user_id, displayname, avatar_url
-                FROM remote_profile_cache
-                WHERE last_check < ?
-            """
-
-            txn.execute(sql, (last_checked,))
-
-            return self.db_pool.cursor_to_dict(txn)
-
-        return await self.db_pool.runInteraction(
-            "get_remote_profile_cache_entries_that_expire",
-            _get_remote_profile_cache_entries_that_expire_txn,
-        )
-
     async def is_subscribed_remote_profile_for_user(self, user_id):
         """Check whether we are interested in a remote user's profile.
         """
@@ -298,3 +263,57 @@ class ProfileStore(ProfileWorkerStore):
 
         if res:
             return True
+
+    async def get_remote_profile_cache_entries_that_expire(
+        self, last_checked: int
+    ) -> List[Dict[str, str]]:
+        """Get all users who haven't been checked since `last_checked`
+        """
+
+        def _get_remote_profile_cache_entries_that_expire_txn(txn):
+            sql = """
+                SELECT user_id, displayname, avatar_url
+                FROM remote_profile_cache
+                WHERE last_check < ?
+            """
+
+            txn.execute(sql, (last_checked,))
+
+            return self.db_pool.cursor_to_dict(txn)
+
+        return await self.db_pool.runInteraction(
+            "get_remote_profile_cache_entries_that_expire",
+            _get_remote_profile_cache_entries_that_expire_txn,
+        )
+
+
+class ProfileStore(ProfileWorkerStore):
+    def __init__(self, database, db_conn, hs):
+        super().__init__(database, db_conn, hs)
+
+        self.db_pool.updates.register_background_index_update(
+            "profile_replication_status_host_index",
+            index_name="profile_replication_status_idx",
+            table="profile_replication_status",
+            columns=["host"],
+            unique=True,
+        )
+
+    async def add_remote_profile_cache(
+        self, user_id: str, displayname: str, avatar_url: str
+    ) -> None:
+        """Ensure we are caching the remote user's profiles.
+
+        This should only be called when `is_subscribed_remote_profile_for_user`
+        would return true for the user.
+        """
+        await self.db_pool.simple_upsert(
+            table="remote_profile_cache",
+            keyvalues={"user_id": user_id},
+            values={
+                "displayname": displayname,
+                "avatar_url": avatar_url,
+                "last_check": self._clock.time_msec(),
+            },
+            desc="add_remote_profile_cache",
+        )
diff --git a/synapse/storage/databases/main/purge_events.py b/synapse/storage/databases/main/purge_events.py
index ecfc6717b3..5d668aadb2 100644
--- a/synapse/storage/databases/main/purge_events.py
+++ b/synapse/storage/databases/main/purge_events.py
@@ -314,6 +314,7 @@ class PurgeEventsStore(StateGroupWorkerStore, SQLBaseStore):
         for table in (
             "event_auth",
             "event_edges",
+            "event_json",
             "event_push_actions_staging",
             "event_reference_hashes",
             "event_relations",
@@ -340,7 +341,6 @@ class PurgeEventsStore(StateGroupWorkerStore, SQLBaseStore):
             "destination_rooms",
             "event_backward_extremities",
             "event_forward_extremities",
-            "event_json",
             "event_push_actions",
             "event_search",
             "events",
diff --git a/synapse/storage/databases/main/pusher.py b/synapse/storage/databases/main/pusher.py
index df8609b97b..7997242d90 100644
--- a/synapse/storage/databases/main/pusher.py
+++ b/synapse/storage/databases/main/pusher.py
@@ -303,7 +303,7 @@ class PusherStore(PusherWorkerStore):
                 lock=False,
             )
 
-            user_has_pusher = self.get_if_user_has_pusher.cache.get(
+            user_has_pusher = self.get_if_user_has_pusher.cache.get_immediate(
                 (user_id,), None, update_metrics=False
             )
 
diff --git a/synapse/storage/databases/main/receipts.py b/synapse/storage/databases/main/receipts.py
index c79ddff680..1e7949a323 100644
--- a/synapse/storage/databases/main/receipts.py
+++ b/synapse/storage/databases/main/receipts.py
@@ -23,8 +23,8 @@ from twisted.internet import defer
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
 from synapse.storage.database import DatabasePool
 from synapse.storage.util.id_generators import StreamIdGenerator
+from synapse.types import JsonDict
 from synapse.util import json_encoder
-from synapse.util.async_helpers import ObservableDeferred
 from synapse.util.caches.descriptors import cached, cachedList
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
@@ -274,6 +274,65 @@ class ReceiptsWorkerStore(SQLBaseStore, metaclass=abc.ABCMeta):
         }
         return results
 
+    @cached(num_args=2,)
+    async def get_linearized_receipts_for_all_rooms(
+        self, to_key: int, from_key: Optional[int] = None
+    ) -> Dict[str, JsonDict]:
+        """Get receipts for all rooms between two stream_ids, up
+        to a limit of the latest 100 read receipts.
+
+        Args:
+            to_key: Max stream id to fetch receipts upto.
+            from_key: Min stream id to fetch receipts from. None fetches
+                from the start.
+
+        Returns:
+            A dictionary of roomids to a list of receipts.
+        """
+
+        def f(txn):
+            if from_key:
+                sql = """
+                    SELECT * FROM receipts_linearized WHERE
+                    stream_id > ? AND stream_id <= ?
+                    ORDER BY stream_id DESC
+                    LIMIT 100
+                """
+                txn.execute(sql, [from_key, to_key])
+            else:
+                sql = """
+                    SELECT * FROM receipts_linearized WHERE
+                    stream_id <= ?
+                    ORDER BY stream_id DESC
+                    LIMIT 100
+                """
+
+                txn.execute(sql, [to_key])
+
+            return self.db_pool.cursor_to_dict(txn)
+
+        txn_results = await self.db_pool.runInteraction(
+            "get_linearized_receipts_for_all_rooms", f
+        )
+
+        results = {}
+        for row in txn_results:
+            # We want a single event per room, since we want to batch the
+            # receipts by room, event and type.
+            room_event = results.setdefault(
+                row["room_id"],
+                {"type": "m.receipt", "room_id": row["room_id"], "content": {}},
+            )
+
+            # The content is of the form:
+            # {"$foo:bar": { "read": { "@user:host": <receipt> }, .. }, .. }
+            event_entry = room_event["content"].setdefault(row["event_id"], {})
+            receipt_type = event_entry.setdefault(row["receipt_type"], {})
+
+            receipt_type[row["user_id"]] = db_to_json(row["data"])
+
+        return results
+
     async def get_users_sent_receipts_between(
         self, last_id: int, current_id: int
     ) -> List[str]:
@@ -358,18 +417,10 @@ class ReceiptsWorkerStore(SQLBaseStore, metaclass=abc.ABCMeta):
         if receipt_type != "m.read":
             return
 
-        # Returns either an ObservableDeferred or the raw result
-        res = self.get_users_with_read_receipts_in_room.cache.get(
+        res = self.get_users_with_read_receipts_in_room.cache.get_immediate(
             room_id, None, update_metrics=False
         )
 
-        # first handle the ObservableDeferred case
-        if isinstance(res, ObservableDeferred):
-            if res.has_called():
-                res = res.get_result()
-            else:
-                res = None
-
         if res and user_id in res:
             # We'd only be adding to the set, so no point invalidating if the
             # user is already there
diff --git a/synapse/storage/databases/main/registration.py b/synapse/storage/databases/main/registration.py
index 7731e612f4..1624738409 100644
--- a/synapse/storage/databases/main/registration.py
+++ b/synapse/storage/databases/main/registration.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 # Copyright 2017-2018 New Vector Ltd
-# Copyright 2019 The Matrix.org Foundation C.I.C.
+# Copyright 2019,2020 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -14,32 +14,66 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import logging
 import re
-from typing import Any, Dict, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
+
+import attr
 
 from synapse.api.constants import UserTypes
 from synapse.api.errors import Codes, StoreError, SynapseError, ThreepidValidationError
-from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.storage._base import SQLBaseStore
+from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage.database import DatabasePool
-from synapse.storage.types import Cursor
+from synapse.storage.databases.main.cache import CacheInvalidationWorkerStore
+from synapse.storage.databases.main.stats import StatsStore
+from synapse.storage.types import Connection, Cursor
+from synapse.storage.util.id_generators import IdGenerator
 from synapse.storage.util.sequence import build_sequence_generator
 from synapse.types import UserID
 from synapse.util.caches.descriptors import cached
 
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
 THIRTY_MINUTES_IN_MS = 30 * 60 * 1000
 
 logger = logging.getLogger(__name__)
 
 
-class RegistrationWorkerStore(SQLBaseStore):
-    def __init__(self, database: DatabasePool, db_conn, hs):
+@attr.s(frozen=True, slots=True)
+class TokenLookupResult:
+    """Result of looking up an access token.
+
+    Attributes:
+        user_id: The user that this token authenticates as
+        is_guest
+        shadow_banned
+        token_id: The ID of the access token looked up
+        device_id: The device associated with the token, if any.
+        valid_until_ms: The timestamp the token expires, if any.
+        token_owner: The "owner" of the token. This is either the same as the
+            user, or a server admin who is logged in as the user.
+    """
+
+    user_id = attr.ib(type=str)
+    is_guest = attr.ib(type=bool, default=False)
+    shadow_banned = attr.ib(type=bool, default=False)
+    token_id = attr.ib(type=Optional[int], default=None)
+    device_id = attr.ib(type=Optional[str], default=None)
+    valid_until_ms = attr.ib(type=Optional[int], default=None)
+    token_owner = attr.ib(type=str)
+
+    # Make the token owner default to the user ID, which is the common case.
+    @token_owner.default
+    def _default_token_owner(self):
+        return self.user_id
+
+
+class RegistrationWorkerStore(CacheInvalidationWorkerStore):
+    def __init__(self, database: DatabasePool, db_conn: Connection, hs: "HomeServer"):
         super().__init__(database, db_conn, hs)
 
         self.config = hs.config
-        self.clock = hs.get_clock()
 
         # Note: we don't check this sequence for consistency as we'd have to
         # call `find_max_generated_user_id_localpart` each time, which is
@@ -48,6 +82,24 @@ class RegistrationWorkerStore(SQLBaseStore):
             database.engine, find_max_generated_user_id_localpart, "user_id_seq",
         )
 
+        self._account_validity_enabled = hs.config.account_validity_enabled
+        if self._account_validity_enabled:
+            self._account_validity_period = hs.config.account_validity_period
+            self._account_validity_startup_job_max_delta = (
+                hs.config.account_validity_startup_job_max_delta
+            )
+
+            if hs.config.run_background_tasks:
+                self._clock.call_later(
+                    0.0, self._set_expiration_date_when_missing,
+                )
+
+        # Create a background job for culling expired 3PID validity tokens
+        if hs.config.run_background_tasks:
+            self._clock.looping_call(
+                self.cull_expired_threepid_validation_tokens, THIRTY_MINUTES_IN_MS
+            )
+
     @cached()
     async def get_user_by_id(self, user_id: str) -> Optional[Dict[str, Any]]:
         return await self.db_pool.simple_select_one(
@@ -81,21 +133,19 @@ class RegistrationWorkerStore(SQLBaseStore):
         if not info:
             return False
 
-        now = self.clock.time_msec()
+        now = self._clock.time_msec()
         trial_duration_ms = self.config.mau_trial_days * 24 * 60 * 60 * 1000
         is_trial = (now - info["creation_ts"] * 1000) < trial_duration_ms
         return is_trial
 
     @cached()
-    async def get_user_by_access_token(self, token: str) -> Optional[dict]:
+    async def get_user_by_access_token(self, token: str) -> Optional[TokenLookupResult]:
         """Get a user from the given access token.
 
         Args:
             token: The access token of a user.
         Returns:
-            None, if the token did not match, otherwise dict
-            including the keys `name`, `is_guest`, `device_id`, `token_id`,
-            `valid_until_ms`.
+            None, if the token did not match, otherwise a `TokenLookupResult`
         """
         return await self.db_pool.runInteraction(
             "get_user_by_access_token", self._query_for_auth, token
@@ -203,7 +253,7 @@ class RegistrationWorkerStore(SQLBaseStore):
             return [UserID.from_string(row[0]) for row in rows]
 
         res = await self.db_pool.runInteraction(
-            "get_expired_users", get_expired_users_txn, self.clock.time_msec()
+            "get_expired_users", get_expired_users_txn, self._clock.time_msec()
         )
 
         return res
@@ -274,13 +324,13 @@ class RegistrationWorkerStore(SQLBaseStore):
             desc="get_renewal_token_for_user",
         )
 
-    async def get_users_expiring_soon(self) -> List[Dict[str, int]]:
+    async def get_users_expiring_soon(self) -> List[Dict[str, Any]]:
         """Selects users whose account will expire in the [now, now + renew_at] time
         window (see configuration for account_validity for information on what renew_at
         refers to).
 
         Returns:
-            A list of dictionaries mapping user ID to expiration time (in milliseconds).
+            A list of dictionaries, each with a user ID and expiration time (in milliseconds).
         """
 
         def select_users_txn(txn, now_ms, renew_at):
@@ -295,7 +345,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         return await self.db_pool.runInteraction(
             "get_users_expiring_soon",
             select_users_txn,
-            self.clock.time_msec(),
+            self._clock.time_msec(),
             self.config.account_validity_renew_at,
         )
 
@@ -369,7 +419,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         return {
             user_id: {
                 "expired": (
-                    expiration is not None and self.clock.time_msec() >= expiration
+                    expiration is not None and self._clock.time_msec() >= expiration
                 ),
                 "deactivated": deactivated == 1,
             }
@@ -413,19 +463,24 @@ class RegistrationWorkerStore(SQLBaseStore):
 
         await self.db_pool.runInteraction("set_server_admin", set_server_admin_txn)
 
-    def _query_for_auth(self, txn, token):
-        sql = (
-            "SELECT users.name, users.is_guest, users.shadow_banned, access_tokens.id as token_id,"
-            " access_tokens.device_id, access_tokens.valid_until_ms"
-            " FROM users"
-            " INNER JOIN access_tokens on users.name = access_tokens.user_id"
-            " WHERE token = ?"
-        )
+    def _query_for_auth(self, txn, token: str) -> Optional[TokenLookupResult]:
+        sql = """
+            SELECT users.name as user_id,
+                users.is_guest,
+                users.shadow_banned,
+                access_tokens.id as token_id,
+                access_tokens.device_id,
+                access_tokens.valid_until_ms,
+                access_tokens.user_id as token_owner
+            FROM users
+            INNER JOIN access_tokens on users.name = COALESCE(puppets_user_id, access_tokens.user_id)
+            WHERE token = ?
+        """
 
         txn.execute(sql, (token,))
         rows = self.db_pool.cursor_to_dict(txn)
         if rows:
-            return rows[0]
+            return TokenLookupResult(**rows[0])
 
         return None
 
@@ -875,12 +930,111 @@ class RegistrationWorkerStore(SQLBaseStore):
             "delete_threepid_session", delete_threepid_session_txn
         )
 
+    @wrap_as_background_process("cull_expired_threepid_validation_tokens")
+    async def cull_expired_threepid_validation_tokens(self) -> None:
+        """Remove threepid validation tokens with expiry dates that have passed"""
+
+        def cull_expired_threepid_validation_tokens_txn(txn, ts):
+            sql = """
+            DELETE FROM threepid_validation_token WHERE
+            expires < ?
+            """
+            txn.execute(sql, (ts,))
+
+        await self.db_pool.runInteraction(
+            "cull_expired_threepid_validation_tokens",
+            cull_expired_threepid_validation_tokens_txn,
+            self._clock.time_msec(),
+        )
+
+    @wrap_as_background_process("account_validity_set_expiration_dates")
+    async def _set_expiration_date_when_missing(self):
+        """
+        Retrieves the list of registered users that don't have an expiration date, and
+        adds an expiration date for each of them.
+        """
+
+        def select_users_with_no_expiration_date_txn(txn):
+            """Retrieves the list of registered users with no expiration date from the
+            database, filtering out deactivated users.
+            """
+            sql = (
+                "SELECT users.name FROM users"
+                " LEFT JOIN account_validity ON (users.name = account_validity.user_id)"
+                " WHERE account_validity.user_id is NULL AND users.deactivated = 0;"
+            )
+            txn.execute(sql, [])
+
+            res = self.db_pool.cursor_to_dict(txn)
+            if res:
+                for user in res:
+                    self.set_expiration_date_for_user_txn(
+                        txn, user["name"], use_delta=True
+                    )
+
+        await self.db_pool.runInteraction(
+            "get_users_with_no_expiration_date",
+            select_users_with_no_expiration_date_txn,
+        )
+
+    def set_expiration_date_for_user_txn(self, txn, user_id, use_delta=False):
+        """Sets an expiration date to the account with the given user ID.
+
+        Args:
+             user_id (str): User ID to set an expiration date for.
+             use_delta (bool): If set to False, the expiration date for the user will be
+                now + validity period. If set to True, this expiration date will be a
+                random value in the [now + period - d ; now + period] range, d being a
+                delta equal to 10% of the validity period.
+        """
+        now_ms = self._clock.time_msec()
+        expiration_ts = now_ms + self._account_validity_period
+
+        if use_delta:
+            expiration_ts = self.rand.randrange(
+                expiration_ts - self._account_validity_startup_job_max_delta,
+                expiration_ts,
+            )
+
+        self.db_pool.simple_upsert_txn(
+            txn,
+            "account_validity",
+            keyvalues={"user_id": user_id},
+            values={"expiration_ts_ms": expiration_ts, "email_sent": False},
+        )
+
+    async def get_user_pending_deactivation(self) -> Optional[str]:
+        """
+        Gets one user from the table of users waiting to be parted from all the rooms
+        they're in.
+        """
+        return await self.db_pool.simple_select_one_onecol(
+            "users_pending_deactivation",
+            keyvalues={},
+            retcol="user_id",
+            allow_none=True,
+            desc="get_users_pending_deactivation",
+        )
+
+    async def del_user_pending_deactivation(self, user_id: str) -> None:
+        """
+        Removes the given user to the table of users who need to be parted from all the
+        rooms they're in, effectively marking that user as fully deactivated.
+        """
+        # XXX: This should be simple_delete_one but we failed to put a unique index on
+        # the table, so somehow duplicate entries have ended up in it.
+        await self.db_pool.simple_delete(
+            "users_pending_deactivation",
+            keyvalues={"user_id": user_id},
+            desc="del_user_pending_deactivation",
+        )
+
 
 class RegistrationBackgroundUpdateStore(RegistrationWorkerStore):
-    def __init__(self, database: DatabasePool, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn: Connection, hs: "HomeServer"):
         super().__init__(database, db_conn, hs)
 
-        self.clock = hs.get_clock()
+        self._clock = hs.get_clock()
         self.config = hs.config
 
         self.db_pool.updates.register_background_index_update(
@@ -1003,38 +1157,55 @@ class RegistrationBackgroundUpdateStore(RegistrationWorkerStore):
 
         return 1
 
+    async def set_user_deactivated_status(
+        self, user_id: str, deactivated: bool
+    ) -> None:
+        """Set the `deactivated` property for the provided user to the provided value.
 
-class RegistrationStore(RegistrationBackgroundUpdateStore):
-    def __init__(self, database: DatabasePool, db_conn, hs):
+        Args:
+            user_id: The ID of the user to set the status for.
+            deactivated: The value to set for `deactivated`.
+        """
+
+        await self.db_pool.runInteraction(
+            "set_user_deactivated_status",
+            self.set_user_deactivated_status_txn,
+            user_id,
+            deactivated,
+        )
+
+    def set_user_deactivated_status_txn(self, txn, user_id: str, deactivated: bool):
+        self.db_pool.simple_update_one_txn(
+            txn=txn,
+            table="users",
+            keyvalues={"name": user_id},
+            updatevalues={"deactivated": 1 if deactivated else 0},
+        )
+        self._invalidate_cache_and_stream(
+            txn, self.get_user_deactivated_status, (user_id,)
+        )
+        txn.call_after(self.is_guest.invalidate, (user_id,))
+
+    @cached()
+    async def is_guest(self, user_id: str) -> bool:
+        res = await self.db_pool.simple_select_one_onecol(
+            table="users",
+            keyvalues={"name": user_id},
+            retcol="is_guest",
+            allow_none=True,
+            desc="is_guest",
+        )
+
+        return res if res else False
+
+
+class RegistrationStore(StatsStore, RegistrationBackgroundUpdateStore):
+    def __init__(self, database: DatabasePool, db_conn: Connection, hs: "HomeServer"):
         super().__init__(database, db_conn, hs)
 
-        self._account_validity_enabled = hs.config.account_validity_enabled
         self._ignore_unknown_session_error = hs.config.request_token_inhibit_3pid_errors
 
-        self._account_validity_period = None
-        self._account_validity_startup_job_max_delta = None
-        if self._account_validity_enabled:
-            self._account_validity_period = hs.config.account_validity_period
-            self._account_validity_startup_job_max_delta = (
-                hs.config.account_validity_startup_job_max_delta
-            )
-            self._clock.call_later(
-                0.0,
-                run_as_background_process,
-                "account_validity_set_expiration_dates",
-                self._set_expiration_date_when_missing,
-            )
-
-        # Create a background job for culling expired 3PID validity tokens
-        def start_cull():
-            # run as a background process to make sure that the database transactions
-            # have a logcontext to report to
-            return run_as_background_process(
-                "cull_expired_threepid_validation_tokens",
-                self.cull_expired_threepid_validation_tokens,
-            )
-
-        hs.get_clock().looping_call(start_cull, THIRTY_MINUTES_IN_MS)
+        self._access_tokens_id_gen = IdGenerator(db_conn, "access_tokens", "id")
 
     async def add_access_token_to_user(
         self,
@@ -1042,7 +1213,8 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         token: str,
         device_id: Optional[str],
         valid_until_ms: Optional[int],
-    ) -> None:
+        puppets_user_id: Optional[str] = None,
+    ) -> int:
         """Adds an access token for the given user.
 
         Args:
@@ -1052,6 +1224,8 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             valid_until_ms: when the token is valid until. None for no expiry.
         Raises:
             StoreError if there was a problem adding this.
+        Returns:
+            The token ID
         """
         next_id = self._access_tokens_id_gen.get_next()
 
@@ -1063,10 +1237,43 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                 "token": token,
                 "device_id": device_id,
                 "valid_until_ms": valid_until_ms,
+                "puppets_user_id": puppets_user_id,
             },
             desc="add_access_token_to_user",
         )
 
+        return next_id
+
+    def _set_device_for_access_token_txn(self, txn, token: str, device_id: str) -> str:
+        old_device_id = self.db_pool.simple_select_one_onecol_txn(
+            txn, "access_tokens", {"token": token}, "device_id"
+        )
+
+        self.db_pool.simple_update_txn(
+            txn, "access_tokens", {"token": token}, {"device_id": device_id}
+        )
+
+        self._invalidate_cache_and_stream(txn, self.get_user_by_access_token, (token,))
+
+        return old_device_id
+
+    async def set_device_for_access_token(self, token: str, device_id: str) -> str:
+        """Sets the device ID associated with an access token.
+
+        Args:
+            token: The access token to modify.
+            device_id: The new device ID.
+        Returns:
+            The old device ID associated with the access token.
+        """
+
+        return await self.db_pool.runInteraction(
+            "set_device_for_access_token",
+            self._set_device_for_access_token_txn,
+            token,
+            device_id,
+        )
+
     async def register_user(
         self,
         user_id: str,
@@ -1117,19 +1324,19 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
     def _register_user(
         self,
         txn,
-        user_id,
-        password_hash,
-        was_guest,
-        make_guest,
-        appservice_id,
-        create_profile_with_displayname,
-        admin,
-        user_type,
-        shadow_banned,
+        user_id: str,
+        password_hash: Optional[str],
+        was_guest: bool,
+        make_guest: bool,
+        appservice_id: Optional[str],
+        create_profile_with_displayname: Optional[str],
+        admin: bool,
+        user_type: Optional[str],
+        shadow_banned: bool,
     ):
         user_id_obj = UserID.from_string(user_id)
 
-        now = int(self.clock.time())
+        now = int(self._clock.time())
 
         try:
             if was_guest:
@@ -1224,7 +1431,9 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             desc="record_user_external_id",
         )
 
-    async def user_set_password_hash(self, user_id: str, password_hash: str) -> None:
+    async def user_set_password_hash(
+        self, user_id: str, password_hash: Optional[str]
+    ) -> None:
         """
         NB. This does *not* evict any cache because the one use for this
             removes most of the entries subsequently anyway so it would be
@@ -1351,18 +1560,6 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
 
         await self.db_pool.runInteraction("delete_access_token", f)
 
-    @cached()
-    async def is_guest(self, user_id: str) -> bool:
-        res = await self.db_pool.simple_select_one_onecol(
-            table="users",
-            keyvalues={"name": user_id},
-            retcol="is_guest",
-            allow_none=True,
-            desc="is_guest",
-        )
-
-        return res if res else False
-
     async def add_user_pending_deactivation(self, user_id: str) -> None:
         """
         Adds a user to the table of users who need to be parted from all the rooms they're
@@ -1374,32 +1571,6 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             desc="add_user_pending_deactivation",
         )
 
-    async def del_user_pending_deactivation(self, user_id: str) -> None:
-        """
-        Removes the given user to the table of users who need to be parted from all the
-        rooms they're in, effectively marking that user as fully deactivated.
-        """
-        # XXX: This should be simple_delete_one but we failed to put a unique index on
-        # the table, so somehow duplicate entries have ended up in it.
-        await self.db_pool.simple_delete(
-            "users_pending_deactivation",
-            keyvalues={"user_id": user_id},
-            desc="del_user_pending_deactivation",
-        )
-
-    async def get_user_pending_deactivation(self) -> Optional[str]:
-        """
-        Gets one user from the table of users waiting to be parted from all the rooms
-        they're in.
-        """
-        return await self.db_pool.simple_select_one_onecol(
-            "users_pending_deactivation",
-            keyvalues={},
-            retcol="user_id",
-            allow_none=True,
-            desc="get_users_pending_deactivation",
-        )
-
     async def validate_threepid_session(
         self, session_id: str, client_secret: str, token: str, current_ts: int
     ) -> Optional[str]:
@@ -1482,7 +1653,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                 txn,
                 table="threepid_validation_session",
                 keyvalues={"session_id": session_id},
-                updatevalues={"validated_at": self.clock.time_msec()},
+                updatevalues={"validated_at": self._clock.time_msec()},
             )
 
             return next_link
@@ -1550,106 +1721,6 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             start_or_continue_validation_session_txn,
         )
 
-    async def cull_expired_threepid_validation_tokens(self) -> None:
-        """Remove threepid validation tokens with expiry dates that have passed"""
-
-        def cull_expired_threepid_validation_tokens_txn(txn, ts):
-            sql = """
-            DELETE FROM threepid_validation_token WHERE
-            expires < ?
-            """
-            txn.execute(sql, (ts,))
-
-        await self.db_pool.runInteraction(
-            "cull_expired_threepid_validation_tokens",
-            cull_expired_threepid_validation_tokens_txn,
-            self.clock.time_msec(),
-        )
-
-    async def set_user_deactivated_status(
-        self, user_id: str, deactivated: bool
-    ) -> None:
-        """Set the `deactivated` property for the provided user to the provided value.
-
-        Args:
-            user_id: The ID of the user to set the status for.
-            deactivated: The value to set for `deactivated`.
-        """
-
-        await self.db_pool.runInteraction(
-            "set_user_deactivated_status",
-            self.set_user_deactivated_status_txn,
-            user_id,
-            deactivated,
-        )
-
-    def set_user_deactivated_status_txn(self, txn, user_id, deactivated):
-        self.db_pool.simple_update_one_txn(
-            txn=txn,
-            table="users",
-            keyvalues={"name": user_id},
-            updatevalues={"deactivated": 1 if deactivated else 0},
-        )
-        self._invalidate_cache_and_stream(
-            txn, self.get_user_deactivated_status, (user_id,)
-        )
-        txn.call_after(self.is_guest.invalidate, (user_id,))
-
-    async def _set_expiration_date_when_missing(self):
-        """
-        Retrieves the list of registered users that don't have an expiration date, and
-        adds an expiration date for each of them.
-        """
-
-        def select_users_with_no_expiration_date_txn(txn):
-            """Retrieves the list of registered users with no expiration date from the
-            database, filtering out deactivated users.
-            """
-            sql = (
-                "SELECT users.name FROM users"
-                " LEFT JOIN account_validity ON (users.name = account_validity.user_id)"
-                " WHERE account_validity.user_id is NULL AND users.deactivated = 0;"
-            )
-            txn.execute(sql, [])
-
-            res = self.db_pool.cursor_to_dict(txn)
-            if res:
-                for user in res:
-                    self.set_expiration_date_for_user_txn(
-                        txn, user["name"], use_delta=True
-                    )
-
-        await self.db_pool.runInteraction(
-            "get_users_with_no_expiration_date",
-            select_users_with_no_expiration_date_txn,
-        )
-
-    def set_expiration_date_for_user_txn(self, txn, user_id, use_delta=False):
-        """Sets an expiration date to the account with the given user ID.
-
-        Args:
-             user_id (str): User ID to set an expiration date for.
-             use_delta (bool): If set to False, the expiration date for the user will be
-                now + validity period. If set to True, this expiration date will be a
-                random value in the [now + period - d ; now + period] range, d being a
-                delta equal to 10% of the validity period.
-        """
-        now_ms = self._clock.time_msec()
-        expiration_ts = now_ms + self._account_validity_period
-
-        if use_delta:
-            expiration_ts = self.rand.randrange(
-                expiration_ts - self._account_validity_startup_job_max_delta,
-                expiration_ts,
-            )
-
-        self.db_pool.simple_upsert_txn(
-            txn,
-            "account_validity",
-            keyvalues={"user_id": user_id},
-            values={"expiration_ts_ms": expiration_ts, "email_sent": False},
-        )
-
 
 def find_max_generated_user_id_localpart(cur: Cursor) -> int:
     """
diff --git a/synapse/storage/databases/main/room.py b/synapse/storage/databases/main/room.py
index 8fab8de973..4808bf6294 100644
--- a/synapse/storage/databases/main/room.py
+++ b/synapse/storage/databases/main/room.py
@@ -192,6 +192,18 @@ class RoomWorkerStore(SQLBaseStore):
             "count_public_rooms", _count_public_rooms_txn
         )
 
+    async def get_room_count(self) -> int:
+        """Retrieve the total number of rooms.
+        """
+
+        def f(txn):
+            sql = "SELECT count(*)  FROM rooms"
+            txn.execute(sql)
+            row = txn.fetchone()
+            return row[0] or 0
+
+        return await self.db_pool.runInteraction("get_rooms", f)
+
     async def get_largest_public_rooms(
         self,
         network_tuple: Optional[ThirdPartyInstanceID],
@@ -879,6 +891,89 @@ class RoomWorkerStore(SQLBaseStore):
             "get_all_new_public_rooms", get_all_new_public_rooms
         )
 
+    async def get_rooms_for_retention_period_in_range(
+        self, min_ms: Optional[int], max_ms: Optional[int], include_null: bool = False
+    ) -> Dict[str, dict]:
+        """Retrieves all of the rooms within the given retention range.
+
+        Optionally includes the rooms which don't have a retention policy.
+
+        Args:
+            min_ms: Duration in milliseconds that define the lower limit of
+                the range to handle (exclusive). If None, doesn't set a lower limit.
+            max_ms: Duration in milliseconds that define the upper limit of
+                the range to handle (inclusive). If None, doesn't set an upper limit.
+            include_null: Whether to include rooms which retention policy is NULL
+                in the returned set.
+
+        Returns:
+            The rooms within this range, along with their retention
+            policy. The key is "room_id", and maps to a dict describing the retention
+            policy associated with this room ID. The keys for this nested dict are
+            "min_lifetime" (int|None), and "max_lifetime" (int|None).
+        """
+
+        def get_rooms_for_retention_period_in_range_txn(txn):
+            range_conditions = []
+            args = []
+
+            if min_ms is not None:
+                range_conditions.append("max_lifetime > ?")
+                args.append(min_ms)
+
+            if max_ms is not None:
+                range_conditions.append("max_lifetime <= ?")
+                args.append(max_ms)
+
+            # Do a first query which will retrieve the rooms that have a retention policy
+            # in their current state.
+            sql = """
+                SELECT room_id, min_lifetime, max_lifetime FROM room_retention
+                INNER JOIN current_state_events USING (event_id, room_id)
+                """
+
+            if len(range_conditions):
+                sql += " WHERE (" + " AND ".join(range_conditions) + ")"
+
+                if include_null:
+                    sql += " OR max_lifetime IS NULL"
+
+            txn.execute(sql, args)
+
+            rows = self.db_pool.cursor_to_dict(txn)
+            rooms_dict = {}
+
+            for row in rows:
+                rooms_dict[row["room_id"]] = {
+                    "min_lifetime": row["min_lifetime"],
+                    "max_lifetime": row["max_lifetime"],
+                }
+
+            if include_null:
+                # If required, do a second query that retrieves all of the rooms we know
+                # of so we can handle rooms with no retention policy.
+                sql = "SELECT DISTINCT room_id FROM current_state_events"
+
+                txn.execute(sql)
+
+                rows = self.db_pool.cursor_to_dict(txn)
+
+                # If a room isn't already in the dict (i.e. it doesn't have a retention
+                # policy in its state), add it with a null policy.
+                for row in rows:
+                    if row["room_id"] not in rooms_dict:
+                        rooms_dict[row["room_id"]] = {
+                            "min_lifetime": None,
+                            "max_lifetime": None,
+                        }
+
+            return rooms_dict
+
+        return await self.db_pool.runInteraction(
+            "get_rooms_for_retention_period_in_range",
+            get_rooms_for_retention_period_in_range_txn,
+        )
+
 
 class RoomBackgroundUpdateStore(SQLBaseStore):
     REMOVE_TOMESTONED_ROOMS_BG_UPDATE = "remove_tombstoned_rooms_from_directory"
@@ -1167,13 +1262,15 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
             logger.error("store_room with room_id=%s failed: %s", room_id, e)
             raise StoreError(500, "Problem creating room.")
 
-    async def maybe_store_room_on_invite(self, room_id: str, room_version: RoomVersion):
+    async def maybe_store_room_on_outlier_membership(
+        self, room_id: str, room_version: RoomVersion
+    ):
         """
-        When we receive an invite over federation, store the version of the room if we
-        don't already know the room version.
+        When we receive an invite or any other event over federation that may relate to a room
+        we are not in, store the version of the room if we don't already know the room version.
         """
         await self.db_pool.simple_upsert(
-            desc="maybe_store_room_on_invite",
+            desc="maybe_store_room_on_outlier_membership",
             table="rooms",
             keyvalues={"room_id": room_id},
             values={},
@@ -1314,18 +1411,6 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
             )
         self.hs.get_notifier().on_new_replication_data()
 
-    async def get_room_count(self) -> int:
-        """Retrieve the total number of rooms.
-        """
-
-        def f(txn):
-            sql = "SELECT count(*)  FROM rooms"
-            txn.execute(sql)
-            row = txn.fetchone()
-            return row[0] or 0
-
-        return await self.db_pool.runInteraction("get_rooms", f)
-
     async def add_event_report(
         self,
         room_id: str,
@@ -1350,6 +1435,65 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
             desc="add_event_report",
         )
 
+    async def get_event_report(self, report_id: int) -> Optional[Dict[str, Any]]:
+        """Retrieve an event report
+
+        Args:
+            report_id: ID of reported event in database
+        Returns:
+            event_report: json list of information from event report
+        """
+
+        def _get_event_report_txn(txn, report_id):
+
+            sql = """
+                SELECT
+                    er.id,
+                    er.received_ts,
+                    er.room_id,
+                    er.event_id,
+                    er.user_id,
+                    er.content,
+                    events.sender,
+                    room_stats_state.canonical_alias,
+                    room_stats_state.name,
+                    event_json.json AS event_json
+                FROM event_reports AS er
+                LEFT JOIN events
+                    ON events.event_id = er.event_id
+                JOIN event_json
+                    ON event_json.event_id = er.event_id
+                JOIN room_stats_state
+                    ON room_stats_state.room_id = er.room_id
+                WHERE er.id = ?
+            """
+
+            txn.execute(sql, [report_id])
+            row = txn.fetchone()
+
+            if not row:
+                return None
+
+            event_report = {
+                "id": row[0],
+                "received_ts": row[1],
+                "room_id": row[2],
+                "event_id": row[3],
+                "user_id": row[4],
+                "score": db_to_json(row[5]).get("score"),
+                "reason": db_to_json(row[5]).get("reason"),
+                "sender": row[6],
+                "canonical_alias": row[7],
+                "name": row[8],
+                "event_json": db_to_json(row[9]),
+            }
+
+            return event_report
+
+        return await self.db_pool.runInteraction(
+            "get_event_report", _get_event_report_txn, report_id
+        )
+
     async def get_event_reports_paginate(
         self,
         start: int,
@@ -1407,18 +1551,15 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                     er.room_id,
                     er.event_id,
                     er.user_id,
-                    er.reason,
                     er.content,
                     events.sender,
-                    room_aliases.room_alias,
-                    event_json.json AS event_json
+                    room_stats_state.canonical_alias,
+                    room_stats_state.name
                 FROM event_reports AS er
-                LEFT JOIN room_aliases
-                    ON room_aliases.room_id = er.room_id
-                JOIN events
+                LEFT JOIN events
                     ON events.event_id = er.event_id
-                JOIN event_json
-                    ON event_json.event_id = er.event_id
+                JOIN room_stats_state
+                    ON room_stats_state.room_id = er.room_id
                 {where_clause}
                 ORDER BY er.received_ts {order}
                 LIMIT ?
@@ -1429,15 +1570,29 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
 
             args += [limit, start]
             txn.execute(sql, args)
-            event_reports = self.db_pool.cursor_to_dict(txn)
 
-            if count > 0:
-                for row in event_reports:
-                    try:
-                        row["content"] = db_to_json(row["content"])
-                        row["event_json"] = db_to_json(row["event_json"])
-                    except Exception:
-                        continue
+            event_reports = []
+            for row in txn:
+                try:
+                    s = db_to_json(row[5]).get("score")
+                    r = db_to_json(row[5]).get("reason")
+                except Exception:
+                    logger.error("Unable to parse json from event_reports: %s", row[0])
+                    continue
+                event_reports.append(
+                    {
+                        "id": row[0],
+                        "received_ts": row[1],
+                        "room_id": row[2],
+                        "event_id": row[3],
+                        "user_id": row[4],
+                        "score": s,
+                        "reason": r,
+                        "sender": row[6],
+                        "canonical_alias": row[7],
+                        "name": row[8],
+                    }
+                )
 
             return event_reports, count
 
@@ -1468,88 +1623,3 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
             self.is_room_blocked,
             (room_id,),
         )
-
-    async def get_rooms_for_retention_period_in_range(
-        self, min_ms: Optional[int], max_ms: Optional[int], include_null: bool = False
-    ) -> Dict[str, dict]:
-        """Retrieves all of the rooms within the given retention range.
-
-        Optionally includes the rooms which don't have a retention policy.
-
-        Args:
-            min_ms: Duration in milliseconds that define the lower limit of
-                the range to handle (exclusive). If None, doesn't set a lower limit.
-            max_ms: Duration in milliseconds that define the upper limit of
-                the range to handle (inclusive). If None, doesn't set an upper limit.
-            include_null: Whether to include rooms which retention policy is NULL
-                in the returned set.
-
-        Returns:
-            The rooms within this range, along with their retention
-            policy. The key is "room_id", and maps to a dict describing the retention
-            policy associated with this room ID. The keys for this nested dict are
-            "min_lifetime" (int|None), and "max_lifetime" (int|None).
-        """
-
-        def get_rooms_for_retention_period_in_range_txn(txn):
-            range_conditions = []
-            args = []
-
-            if min_ms is not None:
-                range_conditions.append("max_lifetime > ?")
-                args.append(min_ms)
-
-            if max_ms is not None:
-                range_conditions.append("max_lifetime <= ?")
-                args.append(max_ms)
-
-            # Do a first query which will retrieve the rooms that have a retention policy
-            # in their current state.
-            sql = """
-                SELECT room_id, min_lifetime, max_lifetime FROM room_retention
-                INNER JOIN current_state_events USING (event_id, room_id)
-                """
-
-            if len(range_conditions):
-                sql += " WHERE (" + " AND ".join(range_conditions) + ")"
-
-                if include_null:
-                    sql += " OR max_lifetime IS NULL"
-
-            txn.execute(sql, args)
-
-            rows = self.db_pool.cursor_to_dict(txn)
-            rooms_dict = {}
-
-            for row in rows:
-                rooms_dict[row["room_id"]] = {
-                    "min_lifetime": row["min_lifetime"],
-                    "max_lifetime": row["max_lifetime"],
-                }
-
-            if include_null:
-                # If required, do a second query that retrieves all of the rooms we know
-                # of so we can handle rooms with no retention policy.
-                sql = "SELECT DISTINCT room_id FROM current_state_events"
-
-                txn.execute(sql)
-
-                rows = self.db_pool.cursor_to_dict(txn)
-
-                # If a room isn't already in the dict (i.e. it doesn't have a retention
-                # policy in its state), add it with a null policy.
-                for row in rows:
-                    if row["room_id"] not in rooms_dict:
-                        rooms_dict[row["room_id"]] = {
-                            "min_lifetime": None,
-                            "max_lifetime": None,
-                        }
-
-            return rooms_dict
-
-        rooms = await self.db_pool.runInteraction(
-            "get_rooms_for_retention_period_in_range",
-            get_rooms_for_retention_period_in_range_txn,
-        )
-
-        return rooms
diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py
index 86ffe2479e..dcdaf09682 100644
--- a/synapse/storage/databases/main/roommember.py
+++ b/synapse/storage/databases/main/roommember.py
@@ -14,19 +14,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import TYPE_CHECKING, Dict, FrozenSet, Iterable, List, Optional, Set
+from typing import TYPE_CHECKING, Dict, FrozenSet, Iterable, List, Optional, Set, Tuple
 
 from synapse.api.constants import EventTypes, Membership
 from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
 from synapse.metrics import LaterGauge
-from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.storage._base import (
-    LoggingTransaction,
-    SQLBaseStore,
-    db_to_json,
-    make_in_list_sql_clause,
+from synapse.metrics.background_process_metrics import (
+    run_as_background_process,
+    wrap_as_background_process,
 )
+from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
 from synapse.storage.database import DatabasePool
 from synapse.storage.databases.main.events_worker import EventsWorkerStore
 from synapse.storage.engines import Sqlite3Engine
@@ -60,27 +58,22 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         # background update still running?
         self._current_state_events_membership_up_to_date = False
 
-        txn = LoggingTransaction(
-            db_conn.cursor(),
-            name="_check_safe_current_state_events_membership_updated",
-            database_engine=self.database_engine,
+        txn = db_conn.cursor(
+            txn_name="_check_safe_current_state_events_membership_updated"
         )
         self._check_safe_current_state_events_membership_updated_txn(txn)
         txn.close()
 
-        if self.hs.config.metrics_flags.known_servers:
+        if (
+            self.hs.config.run_background_tasks
+            and self.hs.config.metrics_flags.known_servers
+        ):
             self._known_servers_count = 1
             self.hs.get_clock().looping_call(
-                run_as_background_process,
-                60 * 1000,
-                "_count_known_servers",
-                self._count_known_servers,
+                self._count_known_servers, 60 * 1000,
             )
             self.hs.get_clock().call_later(
-                1000,
-                run_as_background_process,
-                "_count_known_servers",
-                self._count_known_servers,
+                1000, self._count_known_servers,
             )
             LaterGauge(
                 "synapse_federation_known_servers",
@@ -89,6 +82,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
                 lambda: self._known_servers_count,
             )
 
+    @wrap_as_background_process("_count_known_servers")
     async def _count_known_servers(self):
         """
         Count the servers that this server knows about.
@@ -356,6 +350,38 @@ class RoomMemberWorkerStore(EventsWorkerStore):
 
         return results
 
+    async def get_local_current_membership_for_user_in_room(
+        self, user_id: str, room_id: str
+    ) -> Tuple[Optional[str], Optional[str]]:
+        """Retrieve the current local membership state and event ID for a user in a room.
+
+        Args:
+            user_id: The ID of the user.
+            room_id: The ID of the room.
+
+        Returns:
+            A tuple of (membership_type, event_id). Both will be None if a
+                room_id/user_id pair is not found.
+        """
+        # Paranoia check.
+        if not self.hs.is_mine_id(user_id):
+            raise Exception(
+                "Cannot call 'get_local_current_membership_for_user_in_room' on "
+                "non-local user %s" % (user_id,),
+            )
+
+        results_dict = await self.db_pool.simple_select_one(
+            "local_current_membership",
+            {"room_id": room_id, "user_id": user_id},
+            ("membership", "event_id"),
+            allow_none=True,
+            desc="get_local_current_membership_for_user_in_room",
+        )
+        if not results_dict:
+            return None, None
+
+        return results_dict.get("membership"), results_dict.get("event_id")
+
     @cached(max_entries=500000, iterable=True)
     async def get_rooms_for_user_with_stream_ordering(
         self, user_id: str
@@ -535,7 +561,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
             # If we do then we can reuse that result and simply update it with
             # any membership changes in `delta_ids`
             if context.prev_group and context.delta_ids:
-                prev_res = self._get_joined_users_from_context.cache.get(
+                prev_res = self._get_joined_users_from_context.cache.get_immediate(
                     (room_id, context.prev_group), None
                 )
                 if prev_res and isinstance(prev_res, dict):
diff --git a/synapse/storage/databases/main/schema/delta/20/pushers.py b/synapse/storage/databases/main/schema/delta/20/pushers.py
index 3edfcfd783..45b846e6a7 100644
--- a/synapse/storage/databases/main/schema/delta/20/pushers.py
+++ b/synapse/storage/databases/main/schema/delta/20/pushers.py
@@ -66,16 +66,15 @@ def run_create(cur, database_engine, *args, **kwargs):
         row[8] = bytes(row[8]).decode("utf-8")
         row[11] = bytes(row[11]).decode("utf-8")
         cur.execute(
-            database_engine.convert_param_style(
-                """
-            INSERT into pushers2 (
-            id, user_name, access_token, profile_tag, kind,
-            app_id, app_display_name, device_display_name,
-            pushkey, ts, lang, data, last_token, last_success,
-            failing_since
-            ) values (%s)"""
-                % (",".join(["?" for _ in range(len(row))]))
-            ),
+            """
+                INSERT into pushers2 (
+                id, user_name, access_token, profile_tag, kind,
+                app_id, app_display_name, device_display_name,
+                pushkey, ts, lang, data, last_token, last_success,
+                failing_since
+                ) values (%s)
+            """
+            % (",".join(["?" for _ in range(len(row))])),
             row,
         )
         count += 1
diff --git a/synapse/storage/databases/main/schema/delta/25/fts.py b/synapse/storage/databases/main/schema/delta/25/fts.py
index ee675e71ff..21f57825d4 100644
--- a/synapse/storage/databases/main/schema/delta/25/fts.py
+++ b/synapse/storage/databases/main/schema/delta/25/fts.py
@@ -71,8 +71,6 @@ def run_create(cur, database_engine, *args, **kwargs):
             " VALUES (?, ?)"
         )
 
-        sql = database_engine.convert_param_style(sql)
-
         cur.execute(sql, ("event_search", progress_json))
 
 
diff --git a/synapse/storage/databases/main/schema/delta/27/ts.py b/synapse/storage/databases/main/schema/delta/27/ts.py
index b7972cfa8e..1c6058063f 100644
--- a/synapse/storage/databases/main/schema/delta/27/ts.py
+++ b/synapse/storage/databases/main/schema/delta/27/ts.py
@@ -50,8 +50,6 @@ def run_create(cur, database_engine, *args, **kwargs):
             " VALUES (?, ?)"
         )
 
-        sql = database_engine.convert_param_style(sql)
-
         cur.execute(sql, ("event_origin_server_ts", progress_json))
 
 
diff --git a/synapse/storage/databases/main/schema/delta/30/as_users.py b/synapse/storage/databases/main/schema/delta/30/as_users.py
index b42c02710a..7f08fabe9f 100644
--- a/synapse/storage/databases/main/schema/delta/30/as_users.py
+++ b/synapse/storage/databases/main/schema/delta/30/as_users.py
@@ -59,9 +59,7 @@ def run_upgrade(cur, database_engine, config, *args, **kwargs):
         user_chunks = (user_ids[i : i + 100] for i in range(0, len(user_ids), n))
         for chunk in user_chunks:
             cur.execute(
-                database_engine.convert_param_style(
-                    "UPDATE users SET appservice_id = ? WHERE name IN (%s)"
-                    % (",".join("?" for _ in chunk),)
-                ),
+                "UPDATE users SET appservice_id = ? WHERE name IN (%s)"
+                % (",".join("?" for _ in chunk),),
                 [as_id] + chunk,
             )
diff --git a/synapse/storage/databases/main/schema/delta/31/pushers.py b/synapse/storage/databases/main/schema/delta/31/pushers.py
index 9bb504aad5..5be81c806a 100644
--- a/synapse/storage/databases/main/schema/delta/31/pushers.py
+++ b/synapse/storage/databases/main/schema/delta/31/pushers.py
@@ -65,16 +65,15 @@ def run_create(cur, database_engine, *args, **kwargs):
         row = list(row)
         row[12] = token_to_stream_ordering(row[12])
         cur.execute(
-            database_engine.convert_param_style(
-                """
-            INSERT into pushers2 (
-            id, user_name, access_token, profile_tag, kind,
-            app_id, app_display_name, device_display_name,
-            pushkey, ts, lang, data, last_stream_ordering, last_success,
-            failing_since
-            ) values (%s)"""
-                % (",".join(["?" for _ in range(len(row))]))
-            ),
+            """
+                INSERT into pushers2 (
+                id, user_name, access_token, profile_tag, kind,
+                app_id, app_display_name, device_display_name,
+                pushkey, ts, lang, data, last_stream_ordering, last_success,
+                failing_since
+                ) values (%s)
+            """
+            % (",".join(["?" for _ in range(len(row))])),
             row,
         )
         count += 1
diff --git a/synapse/storage/databases/main/schema/delta/31/search_update.py b/synapse/storage/databases/main/schema/delta/31/search_update.py
index 63b757ade6..b84c844e3a 100644
--- a/synapse/storage/databases/main/schema/delta/31/search_update.py
+++ b/synapse/storage/databases/main/schema/delta/31/search_update.py
@@ -55,8 +55,6 @@ def run_create(cur, database_engine, *args, **kwargs):
             " VALUES (?, ?)"
         )
 
-        sql = database_engine.convert_param_style(sql)
-
         cur.execute(sql, ("event_search_order", progress_json))
 
 
diff --git a/synapse/storage/databases/main/schema/delta/33/event_fields.py b/synapse/storage/databases/main/schema/delta/33/event_fields.py
index a3e81eeac7..e928c66a8f 100644
--- a/synapse/storage/databases/main/schema/delta/33/event_fields.py
+++ b/synapse/storage/databases/main/schema/delta/33/event_fields.py
@@ -50,8 +50,6 @@ def run_create(cur, database_engine, *args, **kwargs):
             " VALUES (?, ?)"
         )
 
-        sql = database_engine.convert_param_style(sql)
-
         cur.execute(sql, ("event_fields_sender_url", progress_json))
 
 
diff --git a/synapse/storage/databases/main/schema/delta/33/remote_media_ts.py b/synapse/storage/databases/main/schema/delta/33/remote_media_ts.py
index a26057dfb6..ad875c733a 100644
--- a/synapse/storage/databases/main/schema/delta/33/remote_media_ts.py
+++ b/synapse/storage/databases/main/schema/delta/33/remote_media_ts.py
@@ -23,8 +23,5 @@ def run_create(cur, database_engine, *args, **kwargs):
 
 def run_upgrade(cur, database_engine, *args, **kwargs):
     cur.execute(
-        database_engine.convert_param_style(
-            "UPDATE remote_media_cache SET last_access_ts = ?"
-        ),
-        (int(time.time() * 1000),),
+        "UPDATE remote_media_cache SET last_access_ts = ?", (int(time.time() * 1000),),
     )
diff --git a/synapse/storage/databases/main/schema/delta/56/unique_user_filter_index.py b/synapse/storage/databases/main/schema/delta/56/unique_user_filter_index.py
index 1de8b54961..bb7296852a 100644
--- a/synapse/storage/databases/main/schema/delta/56/unique_user_filter_index.py
+++ b/synapse/storage/databases/main/schema/delta/56/unique_user_filter_index.py
@@ -1,6 +1,8 @@
 import logging
+from io import StringIO
 
 from synapse.storage.engines import PostgresEngine
+from synapse.storage.prepare_database import execute_statements_from_stream
 
 logger = logging.getLogger(__name__)
 
@@ -46,7 +48,4 @@ def run_create(cur, database_engine, *args, **kwargs):
         select_clause,
     )
 
-    if isinstance(database_engine, PostgresEngine):
-        cur.execute(sql)
-    else:
-        cur.executescript(sql)
+    execute_statements_from_stream(cur, StringIO(sql))
diff --git a/synapse/storage/databases/main/schema/delta/57/local_current_membership.py b/synapse/storage/databases/main/schema/delta/57/local_current_membership.py
index 63b5acdcf7..44917f0a2e 100644
--- a/synapse/storage/databases/main/schema/delta/57/local_current_membership.py
+++ b/synapse/storage/databases/main/schema/delta/57/local_current_membership.py
@@ -68,7 +68,6 @@ def run_upgrade(cur, database_engine, config, *args, **kwargs):
                 INNER JOIN room_memberships AS r USING (event_id)
                 WHERE type = 'm.room.member' AND state_key LIKE ?
         """
-    sql = database_engine.convert_param_style(sql)
     cur.execute(sql, ("%:" + config.server_name,))
 
     cur.execute(
diff --git a/synapse/storage/databases/main/schema/delta/58/07add_method_to_thumbnail_constraint.sql.postgres b/synapse/storage/databases/main/schema/delta/58/07add_method_to_thumbnail_constraint.sql.postgres
index b64926e9c9..3275ae2b20 100644
--- a/synapse/storage/databases/main/schema/delta/58/07add_method_to_thumbnail_constraint.sql.postgres
+++ b/synapse/storage/databases/main/schema/delta/58/07add_method_to_thumbnail_constraint.sql.postgres
@@ -20,14 +20,14 @@
  */
 
 -- add new index that includes method to local media
-INSERT INTO background_updates (update_name, progress_json) VALUES
-  ('local_media_repository_thumbnails_method_idx', '{}');
+INSERT INTO background_updates (ordering, update_name, progress_json) VALUES
+  (5807, 'local_media_repository_thumbnails_method_idx', '{}');
 
 -- add new index that includes method to remote media
-INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
-  ('remote_media_repository_thumbnails_method_idx', '{}', 'local_media_repository_thumbnails_method_idx');
+INSERT INTO background_updates (ordering, update_name, progress_json, depends_on) VALUES
+  (5807, 'remote_media_repository_thumbnails_method_idx', '{}', 'local_media_repository_thumbnails_method_idx');
 
 -- drop old index
-INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
-  ('media_repository_drop_index_wo_method', '{}', 'remote_media_repository_thumbnails_method_idx');
+INSERT INTO background_updates (ordering, update_name, progress_json, depends_on) VALUES
+  (5807, 'media_repository_drop_index_wo_method', '{}', 'remote_media_repository_thumbnails_method_idx');
 
diff --git a/synapse/storage/databases/main/schema/delta/58/11dehydration.sql b/synapse/storage/databases/main/schema/delta/58/11dehydration.sql
new file mode 100644
index 0000000000..7851a0a825
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/11dehydration.sql
@@ -0,0 +1,20 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+CREATE TABLE IF NOT EXISTS dehydrated_devices(
+    user_id TEXT NOT NULL PRIMARY KEY,
+    device_id TEXT NOT NULL,
+    device_data TEXT NOT NULL -- JSON-encoded client-defined data
+);
diff --git a/synapse/storage/databases/main/schema/delta/58/11fallback.sql b/synapse/storage/databases/main/schema/delta/58/11fallback.sql
new file mode 100644
index 0000000000..4ed981dbf8
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/11fallback.sql
@@ -0,0 +1,24 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+CREATE TABLE IF NOT EXISTS e2e_fallback_keys_json (
+    user_id TEXT NOT NULL, -- The user this fallback key is for.
+    device_id TEXT NOT NULL, -- The device this fallback key is for.
+    algorithm TEXT NOT NULL, -- Which algorithm this fallback key is for.
+    key_id TEXT NOT NULL, -- An id for suppressing duplicate uploads.
+    key_json TEXT NOT NULL, -- The key as a JSON blob.
+    used BOOLEAN NOT NULL DEFAULT FALSE, -- Whether the key has been used or not.
+    CONSTRAINT e2e_fallback_keys_json_uniqueness UNIQUE (user_id, device_id, algorithm)
+);
diff --git a/synapse/storage/databases/main/schema/delta/58/12room_stats.sql b/synapse/storage/databases/main/schema/delta/58/12room_stats.sql
index cade5dcca8..fd733adf13 100644
--- a/synapse/storage/databases/main/schema/delta/58/12room_stats.sql
+++ b/synapse/storage/databases/main/schema/delta/58/12room_stats.sql
@@ -28,5 +28,5 @@
 -- functionality as the old one. This effectively restarts the background job
 -- from the beginning, without running it twice in a row, supporting both
 -- upgrade usecases.
-INSERT INTO background_updates (update_name, progress_json) VALUES
-    ('populate_stats_process_rooms_2', '{}');
+INSERT INTO background_updates (ordering, update_name, progress_json) VALUES
+    (5812, 'populate_stats_process_rooms_2', '{}');
diff --git a/synapse/storage/databases/main/schema/delta/58/19instance_map.sql.postgres b/synapse/storage/databases/main/schema/delta/58/19instance_map.sql.postgres
new file mode 100644
index 0000000000..841186b826
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/19instance_map.sql.postgres
@@ -0,0 +1,25 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+-- A unique and immutable mapping between instance name and an integer ID. This
+-- lets us refer to instances via a small ID in e.g. stream tokens, without
+-- having to encode the full name.
+CREATE TABLE IF NOT EXISTS instance_map (
+    instance_id SERIAL PRIMARY KEY,
+    instance_name TEXT NOT NULL
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS instance_map_idx ON instance_map(instance_name);
diff --git a/synapse/storage/databases/main/schema/delta/58/19txn_id.sql b/synapse/storage/databases/main/schema/delta/58/19txn_id.sql
new file mode 100644
index 0000000000..b2454121a8
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/19txn_id.sql
@@ -0,0 +1,40 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+-- A map of recent events persisted with transaction IDs. Used to deduplicate
+-- send event requests with the same transaction ID.
+--
+-- Note: transaction IDs are scoped to the room ID/user ID/access token that was
+-- used to make the request.
+--
+-- Note: The foreign key constraints are ON DELETE CASCADE, as if we delete the
+-- events or access token we don't want to try and de-duplicate the event.
+CREATE TABLE IF NOT EXISTS event_txn_id (
+    event_id TEXT NOT NULL,
+    room_id TEXT NOT NULL,
+    user_id TEXT NOT NULL,
+    token_id BIGINT NOT NULL,
+    txn_id TEXT NOT NULL,
+    inserted_ts BIGINT NOT NULL,
+    FOREIGN KEY (event_id)
+        REFERENCES events (event_id) ON DELETE CASCADE,
+    FOREIGN KEY (token_id)
+        REFERENCES access_tokens (id) ON DELETE CASCADE
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS event_txn_id_event_id ON event_txn_id(event_id);
+CREATE UNIQUE INDEX IF NOT EXISTS event_txn_id_txn_id ON event_txn_id(room_id, user_id, token_id, txn_id);
+CREATE INDEX IF NOT EXISTS event_txn_id_ts ON event_txn_id(inserted_ts);
diff --git a/synapse/storage/databases/main/schema/delta/58/20instance_name_event_tables.sql b/synapse/storage/databases/main/schema/delta/58/20instance_name_event_tables.sql
new file mode 100644
index 0000000000..ad1f481428
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/20instance_name_event_tables.sql
@@ -0,0 +1,17 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+ALTER TABLE current_state_delta_stream ADD COLUMN instance_name TEXT;
+ALTER TABLE ex_outlier_stream ADD COLUMN instance_name TEXT;
diff --git a/synapse/storage/databases/main/schema/delta/58/20user_daily_visits.sql b/synapse/storage/databases/main/schema/delta/58/20user_daily_visits.sql
new file mode 100644
index 0000000000..b0b5dcddce
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/20user_daily_visits.sql
@@ -0,0 +1,18 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+ -- Add new column to user_daily_visits to track user agent
+ALTER TABLE user_daily_visits
+    ADD COLUMN user_agent TEXT;
diff --git a/synapse/storage/databases/main/schema/delta/58/21as_device_stream.sql b/synapse/storage/databases/main/schema/delta/58/21as_device_stream.sql
new file mode 100644
index 0000000000..7b84a207fd
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/21as_device_stream.sql
@@ -0,0 +1,17 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+ALTER TABLE application_services_state ADD COLUMN read_receipt_stream_id INT;
+ALTER TABLE application_services_state ADD COLUMN presence_stream_id INT;
\ No newline at end of file
diff --git a/synapse/storage/databases/main/schema/delta/58/21drop_device_max_stream_id.sql b/synapse/storage/databases/main/schema/delta/58/21drop_device_max_stream_id.sql
new file mode 100644
index 0000000000..01ea6eddcf
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/21drop_device_max_stream_id.sql
@@ -0,0 +1 @@
+DROP TABLE device_max_stream_id;
diff --git a/synapse/storage/databases/main/schema/delta/58/22puppet_token.sql b/synapse/storage/databases/main/schema/delta/58/22puppet_token.sql
new file mode 100644
index 0000000000..00a9431a97
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/22puppet_token.sql
@@ -0,0 +1,17 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+-- Whether the access token is an admin token for controlling another user.
+ALTER TABLE access_tokens ADD COLUMN puppets_user_id TEXT;
diff --git a/synapse/storage/databases/main/schema/delta/58/22users_have_local_media.sql b/synapse/storage/databases/main/schema/delta/58/22users_have_local_media.sql
new file mode 100644
index 0000000000..e1a35be831
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/22users_have_local_media.sql
@@ -0,0 +1,2 @@
+INSERT INTO background_updates (ordering, update_name, progress_json) VALUES
+  (5822, 'users_have_local_media', '{}');
diff --git a/synapse/storage/databases/main/schema/delta/58/23e2e_cross_signing_keys_idx.sql b/synapse/storage/databases/main/schema/delta/58/23e2e_cross_signing_keys_idx.sql
new file mode 100644
index 0000000000..75c3915a94
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/23e2e_cross_signing_keys_idx.sql
@@ -0,0 +1,17 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+INSERT INTO background_updates (ordering, update_name, progress_json) VALUES
+  (5823, 'e2e_cross_signing_keys_idx', '{}');
diff --git a/synapse/storage/databases/main/schema/delta/58/24drop_event_json_index.sql b/synapse/storage/databases/main/schema/delta/58/24drop_event_json_index.sql
new file mode 100644
index 0000000000..8a39d54aed
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/58/24drop_event_json_index.sql
@@ -0,0 +1,19 @@
+/* Copyright 2020 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+-- this index is essentially redundant. The only time it was ever used was when purging
+-- rooms - and Synapse 1.24 will change that.
+
+DROP INDEX IF EXISTS event_json_room_id;
diff --git a/synapse/storage/databases/main/stats.py b/synapse/storage/databases/main/stats.py
index 5beb302be3..0cdb3ec1f7 100644
--- a/synapse/storage/databases/main/stats.py
+++ b/synapse/storage/databases/main/stats.py
@@ -16,15 +16,18 @@
 
 import logging
 from collections import Counter
+from enum import Enum
 from itertools import chain
 from typing import Any, Dict, List, Optional, Tuple
 
 from twisted.internet.defer import DeferredLock
 
 from synapse.api.constants import EventTypes, Membership
+from synapse.api.errors import StoreError
 from synapse.storage.database import DatabasePool
 from synapse.storage.databases.main.state_deltas import StateDeltasStore
 from synapse.storage.engines import PostgresEngine
+from synapse.types import JsonDict
 from synapse.util.caches.descriptors import cached
 
 logger = logging.getLogger(__name__)
@@ -59,6 +62,23 @@ TYPE_TO_TABLE = {"room": ("room_stats", "room_id"), "user": ("user_stats", "user
 TYPE_TO_ORIGIN_TABLE = {"room": ("rooms", "room_id"), "user": ("users", "name")}
 
 
+class UserSortOrder(Enum):
+    """
+    Enum to define the sorting method used when returning users
+    with get_users_media_usage_paginate
+
+    MEDIA_LENGTH = ordered by size of uploaded media. Smallest to largest.
+    MEDIA_COUNT = ordered by number of uploaded media. Smallest to largest.
+    USER_ID = ordered alphabetically by `user_id`.
+    DISPLAYNAME = ordered alphabetically by `displayname`
+    """
+
+    MEDIA_LENGTH = "media_length"
+    MEDIA_COUNT = "media_count"
+    USER_ID = "user_id"
+    DISPLAYNAME = "displayname"
+
+
 class StatsStore(StateDeltasStore):
     def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
@@ -882,3 +902,110 @@ class StatsStore(StateDeltasStore):
             complete_with_stream_id=pos,
             absolute_field_overrides={"joined_rooms": joined_rooms},
         )
+
+    async def get_users_media_usage_paginate(
+        self,
+        start: int,
+        limit: int,
+        from_ts: Optional[int] = None,
+        until_ts: Optional[int] = None,
+        order_by: Optional[UserSortOrder] = UserSortOrder.USER_ID.value,
+        direction: Optional[str] = "f",
+        search_term: Optional[str] = None,
+    ) -> Tuple[List[JsonDict], Dict[str, int]]:
+        """Function to retrieve a paginated list of users and their uploaded local media
+        (size and number). This will return a json list of users and the
+        total number of users matching the filter criteria.
+
+        Args:
+            start: offset to begin the query from
+            limit: number of rows to retrieve
+            from_ts: request only media that are created later than this timestamp (ms)
+            until_ts: request only media that are created earlier than this timestamp (ms)
+            order_by: the sort order of the returned list
+            direction: sort ascending or descending
+            search_term: a string to filter user names by
+        Returns:
+            A list of user dicts and an integer representing the total number of
+            users that exist given this query
+        """
+
+        def get_users_media_usage_paginate_txn(txn):
+            filters = []
+            args = [self.hs.config.server_name]
+
+            if search_term:
+                filters.append("(lmr.user_id LIKE ? OR displayname LIKE ?)")
+                args.extend(["@%" + search_term + "%:%", "%" + search_term + "%"])
+
+            if from_ts:
+                filters.append("created_ts >= ?")
+                args.extend([from_ts])
+            if until_ts:
+                filters.append("created_ts <= ?")
+                args.extend([until_ts])
+
+            # Set ordering
+            if UserSortOrder(order_by) == UserSortOrder.MEDIA_LENGTH:
+                order_by_column = "media_length"
+            elif UserSortOrder(order_by) == UserSortOrder.MEDIA_COUNT:
+                order_by_column = "media_count"
+            elif UserSortOrder(order_by) == UserSortOrder.USER_ID:
+                order_by_column = "lmr.user_id"
+            elif UserSortOrder(order_by) == UserSortOrder.DISPLAYNAME:
+                order_by_column = "displayname"
+            else:
+                raise StoreError(
+                    500, "Incorrect value for order_by provided: %s" % order_by
+                )
+
+            if direction == "b":
+                order = "DESC"
+            else:
+                order = "ASC"
+
+            where_clause = "WHERE " + " AND ".join(filters) if len(filters) > 0 else ""
+
+            sql_base = """
+                FROM local_media_repository as lmr
+                LEFT JOIN profiles AS p ON lmr.user_id = '@' || p.user_id || ':' || ?
+                {}
+                GROUP BY lmr.user_id, displayname
+            """.format(
+                where_clause
+            )
+
+            # SQLite does not support SELECT COUNT(*) OVER()
+            sql = """
+                SELECT COUNT(*) FROM (
+                    SELECT lmr.user_id
+                    {sql_base}
+                ) AS count_user_ids
+            """.format(
+                sql_base=sql_base,
+            )
+            txn.execute(sql, args)
+            count = txn.fetchone()[0]
+
+            sql = """
+                SELECT
+                    lmr.user_id,
+                    displayname,
+                    COUNT(lmr.user_id) as media_count,
+                    SUM(media_length) as media_length
+                    {sql_base}
+                ORDER BY {order_by_column} {order}
+                LIMIT ? OFFSET ?
+            """.format(
+                sql_base=sql_base, order_by_column=order_by_column, order=order,
+            )
+
+            args += [limit, start]
+            txn.execute(sql, args)
+            users = self.db_pool.cursor_to_dict(txn)
+
+            return users, count
+
+        return await self.db_pool.runInteraction(
+            "get_users_media_usage_paginate_txn", get_users_media_usage_paginate_txn
+        )
diff --git a/synapse/storage/databases/main/stream.py b/synapse/storage/databases/main/stream.py
index 37249f1e3f..e3b9ff5ca6 100644
--- a/synapse/storage/databases/main/stream.py
+++ b/synapse/storage/databases/main/stream.py
@@ -53,7 +53,9 @@ from synapse.storage.database import (
 )
 from synapse.storage.databases.main.events_worker import EventsWorkerStore
 from synapse.storage.engines import BaseDatabaseEngine, PostgresEngine
+from synapse.storage.util.id_generators import MultiWriterIdGenerator
 from synapse.types import Collection, PersistedEventPosition, RoomStreamToken
+from synapse.util.caches.descriptors import cached
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 if TYPE_CHECKING:
@@ -208,6 +210,55 @@ def _make_generic_sql_bound(
     )
 
 
+def _filter_results(
+    lower_token: Optional[RoomStreamToken],
+    upper_token: Optional[RoomStreamToken],
+    instance_name: str,
+    topological_ordering: int,
+    stream_ordering: int,
+) -> bool:
+    """Returns True if the event persisted by the given instance at the given
+    topological/stream_ordering falls between the two tokens (taking a None
+    token to mean unbounded).
+
+    Used to filter results from fetching events in the DB against the given
+    tokens. This is necessary to handle the case where the tokens include
+    position maps, which we handle by fetching more than necessary from the DB
+    and then filtering (rather than attempting to construct a complicated SQL
+    query).
+    """
+
+    event_historical_tuple = (
+        topological_ordering,
+        stream_ordering,
+    )
+
+    if lower_token:
+        if lower_token.topological is not None:
+            # If these are historical tokens we compare the `(topological, stream)`
+            # tuples.
+            if event_historical_tuple <= lower_token.as_historical_tuple():
+                return False
+
+        else:
+            # If these are live tokens we compare the stream ordering against the
+            # writers stream position.
+            if stream_ordering <= lower_token.get_stream_pos_for_instance(
+                instance_name
+            ):
+                return False
+
+    if upper_token:
+        if upper_token.topological is not None:
+            if upper_token.as_historical_tuple() < event_historical_tuple:
+                return False
+        else:
+            if upper_token.get_stream_pos_for_instance(instance_name) < stream_ordering:
+                return False
+
+    return True
+
+
 def filter_to_clause(event_filter: Optional[Filter]) -> Tuple[str, List[str]]:
     # NB: This may create SQL clauses that don't optimise well (and we don't
     # have indices on all possible clauses). E.g. it may create
@@ -305,7 +356,31 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
         raise NotImplementedError()
 
     def get_room_max_token(self) -> RoomStreamToken:
-        return RoomStreamToken(None, self.get_room_max_stream_ordering())
+        """Get a `RoomStreamToken` that marks the current maximum persisted
+        position of the events stream. Useful to get a token that represents
+        "now".
+
+        The token returned is a "live" token that may have an instance_map
+        component.
+        """
+
+        min_pos = self._stream_id_gen.get_current_token()
+
+        positions = {}
+        if isinstance(self._stream_id_gen, MultiWriterIdGenerator):
+            # The `min_pos` is the minimum position that we know all instances
+            # have finished persisting to, so we only care about instances whose
+            # positions are ahead of that. (Instance positions can be behind the
+            # min position as there are times we can work out that the minimum
+            # position is ahead of the naive minimum across all current
+            # positions. See MultiWriterIdGenerator for details)
+            positions = {
+                i: p
+                for i, p in self._stream_id_gen.get_positions().items()
+                if p > min_pos
+            }
+
+        return RoomStreamToken(None, min_pos, positions)
 
     async def get_room_events_stream_for_rooms(
         self,
@@ -404,25 +479,43 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
         if from_key == to_key:
             return [], from_key
 
-        from_id = from_key.stream
-        to_id = to_key.stream
-
-        has_changed = self._events_stream_cache.has_entity_changed(room_id, from_id)
+        has_changed = self._events_stream_cache.has_entity_changed(
+            room_id, from_key.stream
+        )
 
         if not has_changed:
             return [], from_key
 
         def f(txn):
-            sql = (
-                "SELECT event_id, stream_ordering FROM events WHERE"
-                " room_id = ?"
-                " AND not outlier"
-                " AND stream_ordering > ? AND stream_ordering <= ?"
-                " ORDER BY stream_ordering %s LIMIT ?"
-            ) % (order,)
-            txn.execute(sql, (room_id, from_id, to_id, limit))
+            # To handle tokens with a non-empty instance_map we fetch more
+            # results than necessary and then filter down
+            min_from_id = from_key.stream
+            max_to_id = to_key.get_max_stream_pos()
 
-            rows = [_EventDictReturn(row[0], None, row[1]) for row in txn]
+            sql = """
+                SELECT event_id, instance_name, topological_ordering, stream_ordering
+                FROM events
+                WHERE
+                    room_id = ?
+                    AND not outlier
+                    AND stream_ordering > ? AND stream_ordering <= ?
+                ORDER BY stream_ordering %s LIMIT ?
+            """ % (
+                order,
+            )
+            txn.execute(sql, (room_id, min_from_id, max_to_id, 2 * limit))
+
+            rows = [
+                _EventDictReturn(event_id, None, stream_ordering)
+                for event_id, instance_name, topological_ordering, stream_ordering in txn
+                if _filter_results(
+                    from_key,
+                    to_key,
+                    instance_name,
+                    topological_ordering,
+                    stream_ordering,
+                )
+            ][:limit]
             return rows
 
         rows = await self.db_pool.runInteraction("get_room_events_stream_for_room", f)
@@ -431,7 +524,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
             [r.event_id for r in rows], get_prev_content=True
         )
 
-        self._set_before_and_after(ret, rows, topo_order=from_id is None)
+        self._set_before_and_after(ret, rows, topo_order=False)
 
         if order.lower() == "desc":
             ret.reverse()
@@ -448,31 +541,43 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
     async def get_membership_changes_for_user(
         self, user_id: str, from_key: RoomStreamToken, to_key: RoomStreamToken
     ) -> List[EventBase]:
-        from_id = from_key.stream
-        to_id = to_key.stream
-
         if from_key == to_key:
             return []
 
-        if from_id:
+        if from_key:
             has_changed = self._membership_stream_cache.has_entity_changed(
-                user_id, int(from_id)
+                user_id, int(from_key.stream)
             )
             if not has_changed:
                 return []
 
         def f(txn):
-            sql = (
-                "SELECT m.event_id, stream_ordering FROM events AS e,"
-                " room_memberships AS m"
-                " WHERE e.event_id = m.event_id"
-                " AND m.user_id = ?"
-                " AND e.stream_ordering > ? AND e.stream_ordering <= ?"
-                " ORDER BY e.stream_ordering ASC"
-            )
-            txn.execute(sql, (user_id, from_id, to_id))
+            # To handle tokens with a non-empty instance_map we fetch more
+            # results than necessary and then filter down
+            min_from_id = from_key.stream
+            max_to_id = to_key.get_max_stream_pos()
 
-            rows = [_EventDictReturn(row[0], None, row[1]) for row in txn]
+            sql = """
+                SELECT m.event_id, instance_name, topological_ordering, stream_ordering
+                FROM events AS e, room_memberships AS m
+                WHERE e.event_id = m.event_id
+                    AND m.user_id = ?
+                    AND e.stream_ordering > ? AND e.stream_ordering <= ?
+                ORDER BY e.stream_ordering ASC
+            """
+            txn.execute(sql, (user_id, min_from_id, max_to_id,))
+
+            rows = [
+                _EventDictReturn(event_id, None, stream_ordering)
+                for event_id, instance_name, topological_ordering, stream_ordering in txn
+                if _filter_results(
+                    from_key,
+                    to_key,
+                    instance_name,
+                    topological_ordering,
+                    stream_ordering,
+                )
+            ]
 
             return rows
 
@@ -546,7 +651,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
 
     async def get_room_event_before_stream_ordering(
         self, room_id: str, stream_ordering: int
-    ) -> Tuple[int, int, str]:
+    ) -> Optional[Tuple[int, int, str]]:
         """Gets details of the first event in a room at or before a stream ordering
 
         Args:
@@ -589,19 +694,6 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
             )
             return "t%d-%d" % (topo, token)
 
-    async def get_stream_id_for_event(self, event_id: str) -> int:
-        """The stream ID for an event
-        Args:
-            event_id: The id of the event to look up a stream token for.
-        Raises:
-            StoreError if the event wasn't in the database.
-        Returns:
-            A stream ID.
-        """
-        return await self.db_pool.runInteraction(
-            "get_stream_id_for_event", self.get_stream_id_for_event_txn, event_id,
-        )
-
     def get_stream_id_for_event_txn(
         self, txn: LoggingTransaction, event_id: str, allow_none=False,
     ) -> int:
@@ -979,11 +1071,46 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
         else:
             order = "ASC"
 
+        # The bounds for the stream tokens are complicated by the fact
+        # that we need to handle the instance_map part of the tokens. We do this
+        # by fetching all events between the min stream token and the maximum
+        # stream token (as returned by `RoomStreamToken.get_max_stream_pos`) and
+        # then filtering the results.
+        if from_token.topological is not None:
+            from_bound = (
+                from_token.as_historical_tuple()
+            )  # type: Tuple[Optional[int], int]
+        elif direction == "b":
+            from_bound = (
+                None,
+                from_token.get_max_stream_pos(),
+            )
+        else:
+            from_bound = (
+                None,
+                from_token.stream,
+            )
+
+        to_bound = None  # type: Optional[Tuple[Optional[int], int]]
+        if to_token:
+            if to_token.topological is not None:
+                to_bound = to_token.as_historical_tuple()
+            elif direction == "b":
+                to_bound = (
+                    None,
+                    to_token.stream,
+                )
+            else:
+                to_bound = (
+                    None,
+                    to_token.get_max_stream_pos(),
+                )
+
         bounds = generate_pagination_where_clause(
             direction=direction,
             column_names=("topological_ordering", "stream_ordering"),
-            from_token=from_token.as_tuple(),
-            to_token=to_token.as_tuple() if to_token else None,
+            from_token=from_bound,
+            to_token=to_bound,
             engine=self.database_engine,
         )
 
@@ -993,7 +1120,8 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
             bounds += " AND " + filter_clause
             args.extend(filter_args)
 
-        args.append(int(limit))
+        # We fetch more events as we'll filter the result set
+        args.append(int(limit) * 2)
 
         select_keywords = "SELECT"
         join_clause = ""
@@ -1015,7 +1143,9 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
                 select_keywords += "DISTINCT"
 
         sql = """
-            %(select_keywords)s event_id, topological_ordering, stream_ordering
+            %(select_keywords)s
+                event_id, instance_name,
+                topological_ordering, stream_ordering
             FROM events
             %(join_clause)s
             WHERE outlier = ? AND room_id = ? AND %(bounds)s
@@ -1030,7 +1160,18 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
 
         txn.execute(sql, args)
 
-        rows = [_EventDictReturn(row[0], row[1], row[2]) for row in txn]
+        # Filter the result set.
+        rows = [
+            _EventDictReturn(event_id, topological_ordering, stream_ordering)
+            for event_id, instance_name, topological_ordering, stream_ordering in txn
+            if _filter_results(
+                lower_token=to_token if direction == "b" else from_token,
+                upper_token=from_token if direction == "b" else to_token,
+                instance_name=instance_name,
+                topological_ordering=topological_ordering,
+                stream_ordering=stream_ordering,
+            )
+        ][:limit]
 
         if rows:
             topo = rows[-1].topological_ordering
@@ -1095,6 +1236,58 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta):
 
         return (events, token)
 
+    @cached()
+    async def get_id_for_instance(self, instance_name: str) -> int:
+        """Get a unique, immutable ID that corresponds to the given Synapse worker instance.
+        """
+
+        def _get_id_for_instance_txn(txn):
+            instance_id = self.db_pool.simple_select_one_onecol_txn(
+                txn,
+                table="instance_map",
+                keyvalues={"instance_name": instance_name},
+                retcol="instance_id",
+                allow_none=True,
+            )
+            if instance_id is not None:
+                return instance_id
+
+            # If we don't have an entry upsert one.
+            #
+            # We could do this before the first check, and rely on the cache for
+            # efficiency, but each UPSERT causes the next ID to increment which
+            # can quickly bloat the size of the generated IDs for new instances.
+            self.db_pool.simple_upsert_txn(
+                txn,
+                table="instance_map",
+                keyvalues={"instance_name": instance_name},
+                values={},
+            )
+
+            return self.db_pool.simple_select_one_onecol_txn(
+                txn,
+                table="instance_map",
+                keyvalues={"instance_name": instance_name},
+                retcol="instance_id",
+            )
+
+        return await self.db_pool.runInteraction(
+            "get_id_for_instance", _get_id_for_instance_txn
+        )
+
+    @cached()
+    async def get_name_from_instance_id(self, instance_id: int) -> str:
+        """Get the instance name from an ID previously returned by
+        `get_id_for_instance`.
+        """
+
+        return await self.db_pool.simple_select_one_onecol(
+            table="instance_map",
+            keyvalues={"instance_id": instance_id},
+            retcol="instance_name",
+            desc="get_name_from_instance_id",
+        )
+
 
 class StreamStore(StreamWorkerStore):
     def get_room_max_stream_ordering(self) -> int:
diff --git a/synapse/storage/databases/main/transactions.py b/synapse/storage/databases/main/transactions.py
index 97aed1500e..59207cadd4 100644
--- a/synapse/storage/databases/main/transactions.py
+++ b/synapse/storage/databases/main/transactions.py
@@ -19,7 +19,7 @@ from typing import Iterable, List, Optional, Tuple
 
 from canonicaljson import encode_canonical_json
 
-from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage._base import SQLBaseStore, db_to_json
 from synapse.storage.database import DatabasePool, LoggingTransaction
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
@@ -43,15 +43,33 @@ _UpdateTransactionRow = namedtuple(
 SENTINEL = object()
 
 
-class TransactionStore(SQLBaseStore):
+class TransactionWorkerStore(SQLBaseStore):
+    def __init__(self, database: DatabasePool, db_conn, hs):
+        super().__init__(database, db_conn, hs)
+
+        if hs.config.run_background_tasks:
+            self._clock.looping_call(self._cleanup_transactions, 30 * 60 * 1000)
+
+    @wrap_as_background_process("cleanup_transactions")
+    async def _cleanup_transactions(self) -> None:
+        now = self._clock.time_msec()
+        month_ago = now - 30 * 24 * 60 * 60 * 1000
+
+        def _cleanup_transactions_txn(txn):
+            txn.execute("DELETE FROM received_transactions WHERE ts < ?", (month_ago,))
+
+        await self.db_pool.runInteraction(
+            "_cleanup_transactions", _cleanup_transactions_txn
+        )
+
+
+class TransactionStore(TransactionWorkerStore):
     """A collection of queries for handling PDUs.
     """
 
     def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
 
-        self._clock.looping_call(self._start_cleanup_transactions, 30 * 60 * 1000)
-
         self._destination_retry_cache = ExpiringCache(
             cache_name="get_destination_retry_timings",
             clock=self._clock,
@@ -190,42 +208,56 @@ class TransactionStore(SQLBaseStore):
         """
 
         self._destination_retry_cache.pop(destination, None)
-        return await self.db_pool.runInteraction(
-            "set_destination_retry_timings",
-            self._set_destination_retry_timings,
-            destination,
-            failure_ts,
-            retry_last_ts,
-            retry_interval,
-        )
+        if self.database_engine.can_native_upsert:
+            return await self.db_pool.runInteraction(
+                "set_destination_retry_timings",
+                self._set_destination_retry_timings_native,
+                destination,
+                failure_ts,
+                retry_last_ts,
+                retry_interval,
+                db_autocommit=True,  # Safe as its a single upsert
+            )
+        else:
+            return await self.db_pool.runInteraction(
+                "set_destination_retry_timings",
+                self._set_destination_retry_timings_emulated,
+                destination,
+                failure_ts,
+                retry_last_ts,
+                retry_interval,
+            )
 
-    def _set_destination_retry_timings(
+    def _set_destination_retry_timings_native(
         self, txn, destination, failure_ts, retry_last_ts, retry_interval
     ):
+        assert self.database_engine.can_native_upsert
 
-        if self.database_engine.can_native_upsert:
-            # Upsert retry time interval if retry_interval is zero (i.e. we're
-            # resetting it) or greater than the existing retry interval.
+        # Upsert retry time interval if retry_interval is zero (i.e. we're
+        # resetting it) or greater than the existing retry interval.
+        #
+        # WARNING: This is executed in autocommit, so we shouldn't add any more
+        # SQL calls in here (without being very careful).
+        sql = """
+            INSERT INTO destinations (
+                destination, failure_ts, retry_last_ts, retry_interval
+            )
+                VALUES (?, ?, ?, ?)
+            ON CONFLICT (destination) DO UPDATE SET
+                    failure_ts = EXCLUDED.failure_ts,
+                    retry_last_ts = EXCLUDED.retry_last_ts,
+                    retry_interval = EXCLUDED.retry_interval
+                WHERE
+                    EXCLUDED.retry_interval = 0
+                    OR destinations.retry_interval IS NULL
+                    OR destinations.retry_interval < EXCLUDED.retry_interval
+        """
 
-            sql = """
-                INSERT INTO destinations (
-                    destination, failure_ts, retry_last_ts, retry_interval
-                )
-                    VALUES (?, ?, ?, ?)
-                ON CONFLICT (destination) DO UPDATE SET
-                        failure_ts = EXCLUDED.failure_ts,
-                        retry_last_ts = EXCLUDED.retry_last_ts,
-                        retry_interval = EXCLUDED.retry_interval
-                    WHERE
-                        EXCLUDED.retry_interval = 0
-                        OR destinations.retry_interval IS NULL
-                        OR destinations.retry_interval < EXCLUDED.retry_interval
-            """
-
-            txn.execute(sql, (destination, failure_ts, retry_last_ts, retry_interval))
-
-            return
+        txn.execute(sql, (destination, failure_ts, retry_last_ts, retry_interval))
 
+    def _set_destination_retry_timings_emulated(
+        self, txn, destination, failure_ts, retry_last_ts, retry_interval
+    ):
         self.database_engine.lock_table(txn, "destinations")
 
         # We need to be careful here as the data may have changed from under us
@@ -266,22 +298,6 @@ class TransactionStore(SQLBaseStore):
                 },
             )
 
-    def _start_cleanup_transactions(self):
-        return run_as_background_process(
-            "cleanup_transactions", self._cleanup_transactions
-        )
-
-    async def _cleanup_transactions(self) -> None:
-        now = self._clock.time_msec()
-        month_ago = now - 30 * 24 * 60 * 60 * 1000
-
-        def _cleanup_transactions_txn(txn):
-            txn.execute("DELETE FROM received_transactions WHERE ts < ?", (month_ago,))
-
-        await self.db_pool.runInteraction(
-            "_cleanup_transactions", _cleanup_transactions_txn
-        )
-
     async def store_destination_rooms_entries(
         self, destinations: Iterable[str], room_id: str, stream_ordering: int,
     ) -> None:
diff --git a/synapse/storage/databases/main/ui_auth.py b/synapse/storage/databases/main/ui_auth.py
index 3b9211a6d2..79b7ece330 100644
--- a/synapse/storage/databases/main/ui_auth.py
+++ b/synapse/storage/databases/main/ui_auth.py
@@ -288,8 +288,6 @@ class UIAuthWorkerStore(SQLBaseStore):
         )
         return [(row["user_agent"], row["ip"]) for row in rows]
 
-
-class UIAuthStore(UIAuthWorkerStore):
     async def delete_old_ui_auth_sessions(self, expiration_time: int) -> None:
         """
         Remove sessions which were last used earlier than the expiration time.
@@ -339,3 +337,7 @@ class UIAuthStore(UIAuthWorkerStore):
             iterable=session_ids,
             keyvalues={},
         )
+
+
+class UIAuthStore(UIAuthWorkerStore):
+    pass
diff --git a/synapse/storage/databases/main/user_directory.py b/synapse/storage/databases/main/user_directory.py
index 5a390ff2f6..d87ceec6da 100644
--- a/synapse/storage/databases/main/user_directory.py
+++ b/synapse/storage/databases/main/user_directory.py
@@ -480,21 +480,16 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
             user_id_tuples: iterable of 2-tuple of user IDs.
         """
 
-        def _add_users_who_share_room_txn(txn):
-            self.db_pool.simple_upsert_many_txn(
-                txn,
-                table="users_who_share_private_rooms",
-                key_names=["user_id", "other_user_id", "room_id"],
-                key_values=[
-                    (user_id, other_user_id, room_id)
-                    for user_id, other_user_id in user_id_tuples
-                ],
-                value_names=(),
-                value_values=None,
-            )
-
-        await self.db_pool.runInteraction(
-            "add_users_who_share_room", _add_users_who_share_room_txn
+        await self.db_pool.simple_upsert_many(
+            table="users_who_share_private_rooms",
+            key_names=["user_id", "other_user_id", "room_id"],
+            key_values=[
+                (user_id, other_user_id, room_id)
+                for user_id, other_user_id in user_id_tuples
+            ],
+            value_names=(),
+            value_values=None,
+            desc="add_users_who_share_room",
         )
 
     async def add_users_in_public_rooms(
@@ -508,19 +503,13 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
             user_ids
         """
 
-        def _add_users_in_public_rooms_txn(txn):
-
-            self.db_pool.simple_upsert_many_txn(
-                txn,
-                table="users_in_public_rooms",
-                key_names=["user_id", "room_id"],
-                key_values=[(user_id, room_id) for user_id in user_ids],
-                value_names=(),
-                value_values=None,
-            )
-
-        await self.db_pool.runInteraction(
-            "add_users_in_public_rooms", _add_users_in_public_rooms_txn
+        await self.db_pool.simple_upsert_many(
+            table="users_in_public_rooms",
+            key_names=["user_id", "room_id"],
+            key_values=[(user_id, room_id) for user_id in user_ids],
+            value_names=(),
+            value_values=None,
+            desc="add_users_in_public_rooms",
         )
 
     async def delete_all_from_user_dir(self) -> None:
diff --git a/synapse/storage/persist_events.py b/synapse/storage/persist_events.py
index 72939f3984..70e636b0ba 100644
--- a/synapse/storage/persist_events.py
+++ b/synapse/storage/persist_events.py
@@ -96,7 +96,9 @@ class _EventPeristenceQueue:
 
         Returns:
             defer.Deferred: a deferred which will resolve once the events are
-                persisted. Runs its callbacks *without* a logcontext.
+            persisted. Runs its callbacks *without* a logcontext. The result
+            is the same as that returned by the callback passed to
+            `handle_queue`.
         """
         queue = self._event_persist_queues.setdefault(room_id, deque())
         if queue:
@@ -199,7 +201,7 @@ class EventsPersistenceStorage:
         self,
         events_and_contexts: Iterable[Tuple[EventBase, EventContext]],
         backfilled: bool = False,
-    ) -> RoomStreamToken:
+    ) -> Tuple[List[EventBase], RoomStreamToken]:
         """
         Write events to the database
         Args:
@@ -209,7 +211,11 @@ class EventsPersistenceStorage:
                 which might update the current state etc.
 
         Returns:
-            the stream ordering of the latest persisted event
+            List of events persisted, the current position room stream position.
+            The list of events persisted may not be the same as those passed in
+            if they were deduplicated due to an event already existing that
+            matched the transcation ID; the existing event is returned in such
+            a case.
         """
         partitioned = {}  # type: Dict[str, List[Tuple[EventBase, EventContext]]]
         for event, ctx in events_and_contexts:
@@ -225,19 +231,41 @@ class EventsPersistenceStorage:
         for room_id in partitioned:
             self._maybe_start_persisting(room_id)
 
-        await make_deferred_yieldable(
+        # Each deferred returns a map from event ID to existing event ID if the
+        # event was deduplicated. (The dict may also include other entries if
+        # the event was persisted in a batch with other events).
+        #
+        # Since we use `defer.gatherResults` we need to merge the returned list
+        # of dicts into one.
+        ret_vals = await make_deferred_yieldable(
             defer.gatherResults(deferreds, consumeErrors=True)
         )
+        replaced_events = {}
+        for d in ret_vals:
+            replaced_events.update(d)
 
-        return self.main_store.get_room_max_token()
+        events = []
+        for event, _ in events_and_contexts:
+            existing_event_id = replaced_events.get(event.event_id)
+            if existing_event_id:
+                events.append(await self.main_store.get_event(existing_event_id))
+            else:
+                events.append(event)
+
+        return (
+            events,
+            self.main_store.get_room_max_token(),
+        )
 
     async def persist_event(
         self, event: EventBase, context: EventContext, backfilled: bool = False
-    ) -> Tuple[PersistedEventPosition, RoomStreamToken]:
+    ) -> Tuple[EventBase, PersistedEventPosition, RoomStreamToken]:
         """
         Returns:
-            The stream ordering of `event`, and the stream ordering of the
-            latest persisted event
+            The event, stream ordering of `event`, and the stream ordering of the
+            latest persisted event. The returned event may not match the given
+            event if it was deduplicated due to an existing event matching the
+            transaction ID.
         """
         deferred = self._event_persist_queue.add_to_queue(
             event.room_id, [(event, context)], backfilled=backfilled
@@ -245,17 +273,33 @@ class EventsPersistenceStorage:
 
         self._maybe_start_persisting(event.room_id)
 
-        await make_deferred_yieldable(deferred)
+        # The deferred returns a map from event ID to existing event ID if the
+        # event was deduplicated. (The dict may also include other entries if
+        # the event was persisted in a batch with other events.)
+        replaced_events = await make_deferred_yieldable(deferred)
+        replaced_event = replaced_events.get(event.event_id)
+        if replaced_event:
+            event = await self.main_store.get_event(replaced_event)
 
         event_stream_id = event.internal_metadata.stream_ordering
+        # stream ordering should have been assigned by now
+        assert event_stream_id
 
         pos = PersistedEventPosition(self._instance_name, event_stream_id)
-        return pos, self.main_store.get_room_max_token()
+        return event, pos, self.main_store.get_room_max_token()
 
     def _maybe_start_persisting(self, room_id: str):
+        """Pokes the `_event_persist_queue` to start handling new items in the
+        queue, if not already in progress.
+
+        Causes the deferreds returned by `add_to_queue` to resolve with: a
+        dictionary of event ID to event ID we didn't persist as we already had
+        another event persisted with the same TXN ID.
+        """
+
         async def persisting_queue(item):
             with Measure(self._clock, "persist_events"):
-                await self._persist_events(
+                return await self._persist_events(
                     item.events_and_contexts, backfilled=item.backfilled
                 )
 
@@ -265,12 +309,38 @@ class EventsPersistenceStorage:
         self,
         events_and_contexts: List[Tuple[EventBase, EventContext]],
         backfilled: bool = False,
-    ):
+    ) -> Dict[str, str]:
         """Calculates the change to current state and forward extremities, and
         persists the given events and with those updates.
+
+        Returns:
+            A dictionary of event ID to event ID we didn't persist as we already
+            had another event persisted with the same TXN ID.
         """
+        replaced_events = {}  # type: Dict[str, str]
         if not events_and_contexts:
-            return
+            return replaced_events
+
+        # Check if any of the events have a transaction ID that has already been
+        # persisted, and if so we don't persist it again.
+        #
+        # We should have checked this a long time before we get here, but it's
+        # possible that different send event requests race in such a way that
+        # they both pass the earlier checks. Checking here isn't racey as we can
+        # have only one `_persist_events` per room being called at a time.
+        replaced_events = await self.main_store.get_already_persisted_events(
+            (event for event, _ in events_and_contexts)
+        )
+
+        if replaced_events:
+            events_and_contexts = [
+                (e, ctx)
+                for e, ctx in events_and_contexts
+                if e.event_id not in replaced_events
+            ]
+
+            if not events_and_contexts:
+                return replaced_events
 
         chunks = [
             events_and_contexts[x : x + 100]
@@ -439,6 +509,8 @@ class EventsPersistenceStorage:
 
             await self._handle_potentially_left_users(potentially_left_users)
 
+        return replaced_events
+
     async def _calculate_new_extremities(
         self,
         room_id: str,
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index 4957e77f4c..459754feab 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -13,7 +13,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import imp
 import logging
 import os
@@ -24,9 +23,10 @@ from typing import Optional, TextIO
 import attr
 
 from synapse.config.homeserver import HomeServerConfig
+from synapse.storage.database import LoggingDatabaseConnection
 from synapse.storage.engines import BaseDatabaseEngine
 from synapse.storage.engines.postgres import PostgresEngine
-from synapse.storage.types import Connection, Cursor
+from synapse.storage.types import Cursor
 from synapse.types import Collection
 
 logger = logging.getLogger(__name__)
@@ -67,7 +67,7 @@ UNAPPLIED_DELTA_ON_WORKER_ERROR = (
 
 
 def prepare_database(
-    db_conn: Connection,
+    db_conn: LoggingDatabaseConnection,
     database_engine: BaseDatabaseEngine,
     config: Optional[HomeServerConfig],
     databases: Collection[str] = ["main", "state"],
@@ -89,7 +89,7 @@ def prepare_database(
     """
 
     try:
-        cur = db_conn.cursor()
+        cur = db_conn.cursor(txn_name="prepare_database")
 
         # sqlite does not automatically start transactions for DDL / SELECT statements,
         # so we start one before running anything. This ensures that any upgrades
@@ -258,9 +258,7 @@ def _setup_new_database(cur, database_engine, databases):
             executescript(cur, entry.absolute_path)
 
     cur.execute(
-        database_engine.convert_param_style(
-            "INSERT INTO schema_version (version, upgraded) VALUES (?,?)"
-        ),
+        "INSERT INTO schema_version (version, upgraded) VALUES (?,?)",
         (max_current_ver, False),
     )
 
@@ -486,17 +484,13 @@ def _upgrade_existing_database(
 
             # Mark as done.
             cur.execute(
-                database_engine.convert_param_style(
-                    "INSERT INTO applied_schema_deltas (version, file) VALUES (?,?)"
-                ),
+                "INSERT INTO applied_schema_deltas (version, file) VALUES (?,?)",
                 (v, relative_path),
             )
 
             cur.execute("DELETE FROM schema_version")
             cur.execute(
-                database_engine.convert_param_style(
-                    "INSERT INTO schema_version (version, upgraded) VALUES (?,?)"
-                ),
+                "INSERT INTO schema_version (version, upgraded) VALUES (?,?)",
                 (v, True),
             )
 
@@ -532,10 +526,7 @@ def _apply_module_schema_files(cur, database_engine, modname, names_and_streams)
             schemas to be applied
     """
     cur.execute(
-        database_engine.convert_param_style(
-            "SELECT file FROM applied_module_schemas WHERE module_name = ?"
-        ),
-        (modname,),
+        "SELECT file FROM applied_module_schemas WHERE module_name = ?", (modname,),
     )
     applied_deltas = {d for d, in cur}
     for (name, stream) in names_and_streams:
@@ -553,9 +544,7 @@ def _apply_module_schema_files(cur, database_engine, modname, names_and_streams)
 
         # Mark as done.
         cur.execute(
-            database_engine.convert_param_style(
-                "INSERT INTO applied_module_schemas (module_name, file) VALUES (?,?)"
-            ),
+            "INSERT INTO applied_module_schemas (module_name, file) VALUES (?,?)",
             (modname, name),
         )
 
@@ -627,9 +616,7 @@ def _get_or_create_schema_state(txn, database_engine):
 
     if current_version:
         txn.execute(
-            database_engine.convert_param_style(
-                "SELECT file FROM applied_schema_deltas WHERE version >= ?"
-            ),
+            "SELECT file FROM applied_schema_deltas WHERE version >= ?",
             (current_version,),
         )
         applied_deltas = [d for d, in txn]
diff --git a/synapse/storage/types.py b/synapse/storage/types.py
index 2d2b560e74..9cadcba18f 100644
--- a/synapse/storage/types.py
+++ b/synapse/storage/types.py
@@ -12,7 +12,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Any, Iterable, Iterator, List, Tuple
+from typing import Any, Iterable, Iterator, List, Optional, Tuple
 
 from typing_extensions import Protocol
 
@@ -61,3 +61,9 @@ class Connection(Protocol):
 
     def rollback(self, *args, **kwargs) -> None:
         ...
+
+    def __enter__(self) -> "Connection":
+        ...
+
+    def __exit__(self, exc_type, exc_value, traceback) -> Optional[bool]:
+        ...
diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py
index eccd2d5b7b..02d71302ea 100644
--- a/synapse/storage/util/id_generators.py
+++ b/synapse/storage/util/id_generators.py
@@ -55,7 +55,7 @@ def _load_current_id(db_conn, table, column, step=1):
     """
     # debug logging for https://github.com/matrix-org/synapse/issues/7968
     logger.info("initialising stream generator for %s(%s)", table, column)
-    cur = db_conn.cursor()
+    cur = db_conn.cursor(txn_name="_load_current_id")
     if step == 1:
         cur.execute("SELECT MAX(%s) FROM %s" % (column, table))
     else:
@@ -270,7 +270,7 @@ class MultiWriterIdGenerator:
     def _load_current_ids(
         self, db_conn, table: str, instance_column: str, id_column: str
     ):
-        cur = db_conn.cursor()
+        cur = db_conn.cursor(txn_name="_load_current_ids")
 
         # Load the current positions of all writers for the stream.
         if self._writers:
@@ -284,15 +284,12 @@ class MultiWriterIdGenerator:
                     stream_name = ?
                     AND instance_name != ALL(?)
             """
-            sql = self._db.engine.convert_param_style(sql)
             cur.execute(sql, (self._stream_name, self._writers))
 
             sql = """
                 SELECT instance_name, stream_id FROM stream_positions
                 WHERE stream_name = ?
             """
-            sql = self._db.engine.convert_param_style(sql)
-
             cur.execute(sql, (self._stream_name,))
 
             self._current_positions = {
@@ -341,7 +338,6 @@ class MultiWriterIdGenerator:
                 "instance": instance_column,
                 "cmp": "<=" if self._positive else ">=",
             }
-            sql = self._db.engine.convert_param_style(sql)
             cur.execute(sql, (min_stream_id * self._return_factor,))
 
             self._persisted_upto_position = min_stream_id
@@ -422,7 +418,7 @@ class MultiWriterIdGenerator:
             self._unfinished_ids.discard(next_id)
             self._finished_ids.add(next_id)
 
-            new_cur = None
+            new_cur = None  # type: Optional[int]
 
             if self._unfinished_ids:
                 # If there are unfinished IDs then the new position will be the
@@ -528,6 +524,16 @@ class MultiWriterIdGenerator:
 
         heapq.heappush(self._known_persisted_positions, new_id)
 
+        # If we're a writer and we don't have any active writes we update our
+        # current position to the latest position seen. This allows the instance
+        # to report a recent position when asked, rather than a potentially old
+        # one (if this instance hasn't written anything for a while).
+        our_current_position = self._current_positions.get(self._instance_name)
+        if our_current_position and not self._unfinished_ids:
+            self._current_positions[self._instance_name] = max(
+                our_current_position, new_id
+            )
+
         # We move the current min position up if the minimum current positions
         # of all instances is higher (since by definition all positions less
         # that that have been persisted).
diff --git a/synapse/storage/util/sequence.py b/synapse/storage/util/sequence.py
index 2dd95e2709..4386b6101e 100644
--- a/synapse/storage/util/sequence.py
+++ b/synapse/storage/util/sequence.py
@@ -17,6 +17,7 @@ import logging
 import threading
 from typing import Callable, List, Optional
 
+from synapse.storage.database import LoggingDatabaseConnection
 from synapse.storage.engines import (
     BaseDatabaseEngine,
     IncorrectDatabaseSetup,
@@ -53,7 +54,11 @@ class SequenceGenerator(metaclass=abc.ABCMeta):
 
     @abc.abstractmethod
     def check_consistency(
-        self, db_conn: Connection, table: str, id_column: str, positive: bool = True
+        self,
+        db_conn: LoggingDatabaseConnection,
+        table: str,
+        id_column: str,
+        positive: bool = True,
     ):
         """Should be called during start up to test that the current value of
         the sequence is greater than or equal to the maximum ID in the table.
@@ -82,9 +87,13 @@ class PostgresSequenceGenerator(SequenceGenerator):
         return [i for (i,) in txn]
 
     def check_consistency(
-        self, db_conn: Connection, table: str, id_column: str, positive: bool = True
+        self,
+        db_conn: LoggingDatabaseConnection,
+        table: str,
+        id_column: str,
+        positive: bool = True,
     ):
-        txn = db_conn.cursor()
+        txn = db_conn.cursor(txn_name="sequence.check_consistency")
 
         # First we get the current max ID from the table.
         table_sql = "SELECT GREATEST(%(agg)s(%(id)s), 0) FROM %(table)s" % {
@@ -117,6 +126,8 @@ class PostgresSequenceGenerator(SequenceGenerator):
         if max_stream_id > last_value:
             logger.warning(
                 "Postgres sequence %s is behind table %s: %d < %d",
+                self._sequence_name,
+                table,
                 last_value,
                 max_stream_id,
             )
diff --git a/synapse/types.py b/synapse/types.py
index bc73e3775d..7c9f716804 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -22,12 +22,14 @@ from typing import (
     TYPE_CHECKING,
     Any,
     Dict,
+    Iterable,
     Mapping,
     MutableMapping,
     Optional,
     Tuple,
     Type,
     TypeVar,
+    Union,
 )
 
 import attr
@@ -38,13 +40,14 @@ from unpaddedbase64 import decode_base64
 from synapse.api.errors import Codes, SynapseError
 
 if TYPE_CHECKING:
+    from synapse.appservice.api import ApplicationService
     from synapse.storage.databases.main import DataStore
 
 # define a version of typing.Collection that works on python 3.5
 if sys.version_info[:3] >= (3, 6, 0):
     from typing import Collection
 else:
-    from typing import Container, Iterable, Sized
+    from typing import Container, Sized
 
     T_co = TypeVar("T_co", covariant=True)
 
@@ -74,6 +77,7 @@ class Requester(
             "shadow_banned",
             "device_id",
             "app_service",
+            "authenticated_entity",
         ],
     )
 ):
@@ -104,6 +108,7 @@ class Requester(
             "shadow_banned": self.shadow_banned,
             "device_id": self.device_id,
             "app_server_id": self.app_service.id if self.app_service else None,
+            "authenticated_entity": self.authenticated_entity,
         }
 
     @staticmethod
@@ -129,16 +134,18 @@ class Requester(
             shadow_banned=input["shadow_banned"],
             device_id=input["device_id"],
             app_service=appservice,
+            authenticated_entity=input["authenticated_entity"],
         )
 
 
 def create_requester(
-    user_id,
-    access_token_id=None,
-    is_guest=False,
-    shadow_banned=False,
-    device_id=None,
-    app_service=None,
+    user_id: Union[str, "UserID"],
+    access_token_id: Optional[int] = None,
+    is_guest: Optional[bool] = False,
+    shadow_banned: Optional[bool] = False,
+    device_id: Optional[str] = None,
+    app_service: Optional["ApplicationService"] = None,
+    authenticated_entity: Optional[str] = None,
 ):
     """
     Create a new ``Requester`` object
@@ -151,14 +158,27 @@ def create_requester(
         shadow_banned (bool):  True if the user making this request is shadow-banned.
         device_id (str|None):  device_id which was set at authentication time
         app_service (ApplicationService|None):  the AS requesting on behalf of the user
+        authenticated_entity: The entity that authenticated when making the request.
+            This is different to the user_id when an admin user or the server is
+            "puppeting" the user.
 
     Returns:
         Requester
     """
     if not isinstance(user_id, UserID):
         user_id = UserID.from_string(user_id)
+
+    if authenticated_entity is None:
+        authenticated_entity = user_id.to_string()
+
     return Requester(
-        user_id, access_token_id, is_guest, shadow_banned, device_id, app_service
+        user_id,
+        access_token_id,
+        is_guest,
+        shadow_banned,
+        device_id,
+        app_service,
+        authenticated_entity,
     )
 
 
@@ -298,14 +318,14 @@ mxid_localpart_allowed_characters = set(
 )
 
 
-def contains_invalid_mxid_characters(localpart):
+def contains_invalid_mxid_characters(localpart: str) -> bool:
     """Check for characters not allowed in an mxid or groupid localpart
 
     Args:
-        localpart (basestring): the localpart to be checked
+        localpart: the localpart to be checked
 
     Returns:
-        bool: True if there are any naughty characters
+        True if there are any naughty characters
     """
     return any(c not in mxid_localpart_allowed_characters for c in localpart)
 
@@ -389,7 +409,7 @@ def map_username_to_mxid_localpart(username, case_sensitive=False):
     return username.decode("ascii")
 
 
-@attr.s(frozen=True, slots=True)
+@attr.s(frozen=True, slots=True, cmp=False)
 class RoomStreamToken:
     """Tokens are positions between events. The token "s1" comes after event 1.
 
@@ -411,6 +431,31 @@ class RoomStreamToken:
     event it comes after. Historic tokens start with a "t" followed by the
     "topological_ordering" id of the event it comes after, followed by "-",
     followed by the "stream_ordering" id of the event it comes after.
+
+    There is also a third mode for live tokens where the token starts with "m",
+    which is sometimes used when using sharded event persisters. In this case
+    the events stream is considered to be a set of streams (one for each writer)
+    and the token encodes the vector clock of positions of each writer in their
+    respective streams.
+
+    The format of the token in such case is an initial integer min position,
+    followed by the mapping of instance ID to position separated by '.' and '~':
+
+        m{min_pos}~{writer1}.{pos1}~{writer2}.{pos2}. ...
+
+    The `min_pos` corresponds to the minimum position all writers have persisted
+    up to, and then only writers that are ahead of that position need to be
+    encoded. An example token is:
+
+        m56~2.58~3.59
+
+    Which corresponds to a set of three (or more writers) where instances 2 and
+    3 (these are instance IDs that can be looked up in the DB to fetch the more
+    commonly used instance names) are at positions 58 and 59 respectively, and
+    all other instances are at position 56.
+
+    Note: The `RoomStreamToken` cannot have both a topological part and an
+    instance map.
     """
 
     topological = attr.ib(
@@ -419,6 +464,25 @@ class RoomStreamToken:
     )
     stream = attr.ib(type=int, validator=attr.validators.instance_of(int))
 
+    instance_map = attr.ib(
+        type=Dict[str, int],
+        factory=dict,
+        validator=attr.validators.deep_mapping(
+            key_validator=attr.validators.instance_of(str),
+            value_validator=attr.validators.instance_of(int),
+            mapping_validator=attr.validators.instance_of(dict),
+        ),
+    )
+
+    def __attrs_post_init__(self):
+        """Validates that both `topological` and `instance_map` aren't set.
+        """
+
+        if self.instance_map and self.topological:
+            raise ValueError(
+                "Cannot set both 'topological' and 'instance_map' on 'RoomStreamToken'."
+            )
+
     @classmethod
     async def parse(cls, store: "DataStore", string: str) -> "RoomStreamToken":
         try:
@@ -427,6 +491,20 @@ class RoomStreamToken:
             if string[0] == "t":
                 parts = string[1:].split("-", 1)
                 return cls(topological=int(parts[0]), stream=int(parts[1]))
+            if string[0] == "m":
+                parts = string[1:].split("~")
+                stream = int(parts[0])
+
+                instance_map = {}
+                for part in parts[1:]:
+                    key, value = part.split(".")
+                    instance_id = int(key)
+                    pos = int(value)
+
+                    instance_name = await store.get_name_from_instance_id(instance_id)
+                    instance_map[instance_name] = pos
+
+                return cls(topological=None, stream=stream, instance_map=instance_map,)
         except Exception:
             pass
         raise SynapseError(400, "Invalid token %r" % (string,))
@@ -450,14 +528,61 @@ class RoomStreamToken:
 
         max_stream = max(self.stream, other.stream)
 
-        return RoomStreamToken(None, max_stream)
+        instance_map = {
+            instance: max(
+                self.instance_map.get(instance, self.stream),
+                other.instance_map.get(instance, other.stream),
+            )
+            for instance in set(self.instance_map).union(other.instance_map)
+        }
+
+        return RoomStreamToken(None, max_stream, instance_map)
+
+    def as_historical_tuple(self) -> Tuple[int, int]:
+        """Returns a tuple of `(topological, stream)` for historical tokens.
+
+        Raises if not an historical token (i.e. doesn't have a topological part).
+        """
+        if self.topological is None:
+            raise Exception(
+                "Cannot call `RoomStreamToken.as_historical_tuple` on live token"
+            )
 
-    def as_tuple(self) -> Tuple[Optional[int], int]:
         return (self.topological, self.stream)
 
+    def get_stream_pos_for_instance(self, instance_name: str) -> int:
+        """Get the stream position that the given writer was at at this token.
+
+        This only makes sense for "live" tokens that may have a vector clock
+        component, and so asserts that this is a "live" token.
+        """
+        assert self.topological is None
+
+        # If we don't have an entry for the instance we can assume that it was
+        # at `self.stream`.
+        return self.instance_map.get(instance_name, self.stream)
+
+    def get_max_stream_pos(self) -> int:
+        """Get the maximum stream position referenced in this token.
+
+        The corresponding "min" position is, by definition just `self.stream`.
+
+        This is used to handle tokens that have non-empty `instance_map`, and so
+        reference stream positions after the `self.stream` position.
+        """
+        return max(self.instance_map.values(), default=self.stream)
+
     async def to_string(self, store: "DataStore") -> str:
         if self.topological is not None:
             return "t%d-%d" % (self.topological, self.stream)
+        elif self.instance_map:
+            entries = []
+            for name, pos in self.instance_map.items():
+                instance_id = await store.get_id_for_instance(name)
+                entries.append("{}.{}".format(instance_id, pos))
+
+            encoded_map = "~".join(entries)
+            return "m{}~{}".format(self.stream, encoded_map)
         else:
             return "s%d" % (self.stream,)
 
@@ -549,7 +674,7 @@ class PersistedEventPosition:
     stream = attr.ib(type=int)
 
     def persisted_after(self, token: RoomStreamToken) -> bool:
-        return token.stream < self.stream
+        return token.get_stream_pos_for_instance(self.instance_name) < self.stream
 
     def to_room_stream_token(self) -> RoomStreamToken:
         """Converts the position to a room stream token such that events
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index d55b93d763..517686f0a6 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -18,6 +18,7 @@ import logging
 import re
 
 import attr
+from frozendict import frozendict
 
 from twisted.internet import defer, task
 
@@ -31,9 +32,26 @@ def _reject_invalid_json(val):
     raise ValueError("Invalid JSON value: '%s'" % val)
 
 
-# Create a custom encoder to reduce the whitespace produced by JSON encoding and
-# ensure that valid JSON is produced.
-json_encoder = json.JSONEncoder(allow_nan=False, separators=(",", ":"))
+def _handle_frozendict(obj):
+    """Helper for json_encoder. Makes frozendicts serializable by returning
+    the underlying dict
+    """
+    if type(obj) is frozendict:
+        # fishing the protected dict out of the object is a bit nasty,
+        # but we don't really want the overhead of copying the dict.
+        return obj._dict
+    raise TypeError(
+        "Object of type %s is not JSON serializable" % obj.__class__.__name__
+    )
+
+
+# A custom JSON encoder which:
+#   * handles frozendicts
+#   * produces valid JSON (no NaNs etc)
+#   * reduces redundant whitespace
+json_encoder = json.JSONEncoder(
+    allow_nan=False, separators=(",", ":"), default=_handle_frozendict
+)
 
 # Create a custom decoder to reject Python extensions to JSON.
 json_decoder = json.JSONDecoder(parse_constant=_reject_invalid_json)
diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py
index 8fc05be278..89f0b38535 100644
--- a/synapse/util/caches/__init__.py
+++ b/synapse/util/caches/__init__.py
@@ -16,7 +16,7 @@
 
 import logging
 from sys import intern
-from typing import Callable, Dict, Optional
+from typing import Callable, Dict, Optional, Sized
 
 import attr
 from prometheus_client.core import Gauge
@@ -92,7 +92,7 @@ class CacheMetric:
 def register_cache(
     cache_type: str,
     cache_name: str,
-    cache,
+    cache: Sized,
     collect_callback: Optional[Callable] = None,
     resizable: bool = True,
     resize_callback: Optional[Callable] = None,
@@ -100,12 +100,15 @@ def register_cache(
     """Register a cache object for metric collection and resizing.
 
     Args:
-        cache_type
+        cache_type: a string indicating the "type" of the cache. This is used
+            only for deduplication so isn't too important provided it's constant.
         cache_name: name of the cache
-        cache: cache itself
+        cache: cache itself, which must implement __len__(), and may optionally implement
+             a max_size property
         collect_callback: If given, a function which is called during metric
             collection to update additional metrics.
-        resizable: Whether this cache supports being resized.
+        resizable: Whether this cache supports being resized, in which case either
+            resize_callback must be provided, or the cache must support set_max_size().
         resize_callback: A function which can be called to resize the cache.
 
     Returns:
diff --git a/synapse/util/caches/deferred_cache.py b/synapse/util/caches/deferred_cache.py
new file mode 100644
index 0000000000..601305487c
--- /dev/null
+++ b/synapse/util/caches/deferred_cache.py
@@ -0,0 +1,342 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015, 2016 OpenMarket Ltd
+# Copyright 2018 New Vector Ltd
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import enum
+import threading
+from typing import (
+    Callable,
+    Generic,
+    Iterable,
+    MutableMapping,
+    Optional,
+    TypeVar,
+    Union,
+    cast,
+)
+
+from prometheus_client import Gauge
+
+from twisted.internet import defer
+from twisted.python import failure
+
+from synapse.util.async_helpers import ObservableDeferred
+from synapse.util.caches.lrucache import LruCache
+from synapse.util.caches.treecache import TreeCache, iterate_tree_cache_entry
+
+cache_pending_metric = Gauge(
+    "synapse_util_caches_cache_pending",
+    "Number of lookups currently pending for this cache",
+    ["name"],
+)
+
+T = TypeVar("T")
+KT = TypeVar("KT")
+VT = TypeVar("VT")
+
+
+class _Sentinel(enum.Enum):
+    # defining a sentinel in this way allows mypy to correctly handle the
+    # type of a dictionary lookup.
+    sentinel = object()
+
+
+class DeferredCache(Generic[KT, VT]):
+    """Wraps an LruCache, adding support for Deferred results.
+
+    It expects that each entry added with set() will be a Deferred; likewise get()
+    will return a Deferred.
+    """
+
+    __slots__ = (
+        "cache",
+        "thread",
+        "_pending_deferred_cache",
+    )
+
+    def __init__(
+        self,
+        name: str,
+        max_entries: int = 1000,
+        keylen: int = 1,
+        tree: bool = False,
+        iterable: bool = False,
+        apply_cache_factor_from_config: bool = True,
+    ):
+        """
+        Args:
+            name: The name of the cache
+            max_entries: Maximum amount of entries that the cache will hold
+            keylen: The length of the tuple used as the cache key. Ignored unless
+               `tree` is True.
+            tree: Use a TreeCache instead of a dict as the underlying cache type
+            iterable: If True, count each item in the cached object as an entry,
+                rather than each cached object
+            apply_cache_factor_from_config: Whether cache factors specified in the
+                config file affect `max_entries`
+        """
+        cache_type = TreeCache if tree else dict
+
+        # _pending_deferred_cache maps from the key value to a `CacheEntry` object.
+        self._pending_deferred_cache = (
+            cache_type()
+        )  # type: MutableMapping[KT, CacheEntry]
+
+        def metrics_cb():
+            cache_pending_metric.labels(name).set(len(self._pending_deferred_cache))
+
+        # cache is used for completed results and maps to the result itself, rather than
+        # a Deferred.
+        self.cache = LruCache(
+            max_size=max_entries,
+            keylen=keylen,
+            cache_name=name,
+            cache_type=cache_type,
+            size_callback=(lambda d: len(d)) if iterable else None,
+            metrics_collection_callback=metrics_cb,
+            apply_cache_factor_from_config=apply_cache_factor_from_config,
+        )  # type: LruCache[KT, VT]
+
+        self.thread = None  # type: Optional[threading.Thread]
+
+    @property
+    def max_entries(self):
+        return self.cache.max_size
+
+    def check_thread(self):
+        expected_thread = self.thread
+        if expected_thread is None:
+            self.thread = threading.current_thread()
+        else:
+            if expected_thread is not threading.current_thread():
+                raise ValueError(
+                    "Cache objects can only be accessed from the main thread"
+                )
+
+    def get(
+        self,
+        key: KT,
+        callback: Optional[Callable[[], None]] = None,
+        update_metrics: bool = True,
+    ) -> defer.Deferred:
+        """Looks the key up in the caches.
+
+        For symmetry with set(), this method does *not* follow the synapse logcontext
+        rules: the logcontext will not be cleared on return, and the Deferred will run
+        its callbacks in the sentinel context. In other words: wrap the result with
+        make_deferred_yieldable() before `await`ing it.
+
+        Args:
+            key:
+            callback: Gets called when the entry in the cache is invalidated
+            update_metrics (bool): whether to update the cache hit rate metrics
+
+        Returns:
+            A Deferred which completes with the result. Note that this may later fail
+            if there is an ongoing set() operation which later completes with a failure.
+
+        Raises:
+            KeyError if the key is not found in the cache
+        """
+        callbacks = [callback] if callback else []
+        val = self._pending_deferred_cache.get(key, _Sentinel.sentinel)
+        if val is not _Sentinel.sentinel:
+            val.callbacks.update(callbacks)
+            if update_metrics:
+                m = self.cache.metrics
+                assert m  # we always have a name, so should always have metrics
+                m.inc_hits()
+            return val.deferred.observe()
+
+        val2 = self.cache.get(
+            key, _Sentinel.sentinel, callbacks=callbacks, update_metrics=update_metrics
+        )
+        if val2 is _Sentinel.sentinel:
+            raise KeyError()
+        else:
+            return defer.succeed(val2)
+
+    def get_immediate(
+        self, key: KT, default: T, update_metrics: bool = True
+    ) -> Union[VT, T]:
+        """If we have a *completed* cached value, return it."""
+        return self.cache.get(key, default, update_metrics=update_metrics)
+
+    def set(
+        self,
+        key: KT,
+        value: defer.Deferred,
+        callback: Optional[Callable[[], None]] = None,
+    ) -> defer.Deferred:
+        """Adds a new entry to the cache (or updates an existing one).
+
+        The given `value` *must* be a Deferred.
+
+        First any existing entry for the same key is invalidated. Then a new entry
+        is added to the cache for the given key.
+
+        Until the `value` completes, calls to `get()` for the key will also result in an
+        incomplete Deferred, which will ultimately complete with the same result as
+        `value`.
+
+        If `value` completes successfully, subsequent calls to `get()` will then return
+        a completed deferred with the same result. If it *fails*, the cache is
+        invalidated and subequent calls to `get()` will raise a KeyError.
+
+        If another call to `set()` happens before `value` completes, then (a) any
+        invalidation callbacks registered in the interim will be called, (b) any
+        `get()`s in the interim will continue to complete with the result from the
+        *original* `value`, (c) any future calls to `get()` will complete with the
+        result from the *new* `value`.
+
+        It is expected that `value` does *not* follow the synapse logcontext rules - ie,
+        if it is incomplete, it runs its callbacks in the sentinel context.
+
+        Args:
+            key: Key to be set
+            value: a deferred which will complete with a result to add to the cache
+            callback: An optional callback to be called when the entry is invalidated
+        """
+        if not isinstance(value, defer.Deferred):
+            raise TypeError("not a Deferred")
+
+        callbacks = [callback] if callback else []
+        self.check_thread()
+
+        existing_entry = self._pending_deferred_cache.pop(key, None)
+        if existing_entry:
+            existing_entry.invalidate()
+
+        # XXX: why don't we invalidate the entry in `self.cache` yet?
+
+        # we can save a whole load of effort if the deferred is ready.
+        if value.called:
+            result = value.result
+            if not isinstance(result, failure.Failure):
+                self.cache.set(key, result, callbacks)
+            return value
+
+        # otherwise, we'll add an entry to the _pending_deferred_cache for now,
+        # and add callbacks to add it to the cache properly later.
+
+        observable = ObservableDeferred(value, consumeErrors=True)
+        observer = observable.observe()
+        entry = CacheEntry(deferred=observable, callbacks=callbacks)
+
+        self._pending_deferred_cache[key] = entry
+
+        def compare_and_pop():
+            """Check if our entry is still the one in _pending_deferred_cache, and
+            if so, pop it.
+
+            Returns true if the entries matched.
+            """
+            existing_entry = self._pending_deferred_cache.pop(key, None)
+            if existing_entry is entry:
+                return True
+
+            # oops, the _pending_deferred_cache has been updated since
+            # we started our query, so we are out of date.
+            #
+            # Better put back whatever we took out. (We do it this way
+            # round, rather than peeking into the _pending_deferred_cache
+            # and then removing on a match, to make the common case faster)
+            if existing_entry is not None:
+                self._pending_deferred_cache[key] = existing_entry
+
+            return False
+
+        def cb(result):
+            if compare_and_pop():
+                self.cache.set(key, result, entry.callbacks)
+            else:
+                # we're not going to put this entry into the cache, so need
+                # to make sure that the invalidation callbacks are called.
+                # That was probably done when _pending_deferred_cache was
+                # updated, but it's possible that `set` was called without
+                # `invalidate` being previously called, in which case it may
+                # not have been. Either way, let's double-check now.
+                entry.invalidate()
+
+        def eb(_fail):
+            compare_and_pop()
+            entry.invalidate()
+
+        # once the deferred completes, we can move the entry from the
+        # _pending_deferred_cache to the real cache.
+        #
+        observer.addCallbacks(cb, eb)
+
+        # we return a new Deferred which will be called before any subsequent observers.
+        return observable.observe()
+
+    def prefill(self, key: KT, value: VT, callback: Callable[[], None] = None):
+        callbacks = [callback] if callback else []
+        self.cache.set(key, value, callbacks=callbacks)
+
+    def invalidate(self, key):
+        self.check_thread()
+        self.cache.pop(key, None)
+
+        # if we have a pending lookup for this key, remove it from the
+        # _pending_deferred_cache, which will (a) stop it being returned
+        # for future queries and (b) stop it being persisted as a proper entry
+        # in self.cache.
+        entry = self._pending_deferred_cache.pop(key, None)
+
+        # run the invalidation callbacks now, rather than waiting for the
+        # deferred to resolve.
+        if entry:
+            entry.invalidate()
+
+    def invalidate_many(self, key: KT):
+        self.check_thread()
+        if not isinstance(key, tuple):
+            raise TypeError("The cache key must be a tuple not %r" % (type(key),))
+        key = cast(KT, key)
+        self.cache.del_multi(key)
+
+        # if we have a pending lookup for this key, remove it from the
+        # _pending_deferred_cache, as above
+        entry_dict = self._pending_deferred_cache.pop(key, None)
+        if entry_dict is not None:
+            for entry in iterate_tree_cache_entry(entry_dict):
+                entry.invalidate()
+
+    def invalidate_all(self):
+        self.check_thread()
+        self.cache.clear()
+        for entry in self._pending_deferred_cache.values():
+            entry.invalidate()
+        self._pending_deferred_cache.clear()
+
+
+class CacheEntry:
+    __slots__ = ["deferred", "callbacks", "invalidated"]
+
+    def __init__(
+        self, deferred: ObservableDeferred, callbacks: Iterable[Callable[[], None]]
+    ):
+        self.deferred = deferred
+        self.callbacks = set(callbacks)
+        self.invalidated = False
+
+    def invalidate(self):
+        if not self.invalidated:
+            self.invalidated = True
+            for callback in self.callbacks:
+                callback()
+            self.callbacks.clear()
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index 98b34f2223..a924140cdf 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -13,25 +13,31 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+import enum
 import functools
 import inspect
 import logging
-import threading
-from typing import Any, Callable, Generic, Optional, Tuple, TypeVar, Union, cast
+from typing import (
+    Any,
+    Callable,
+    Generic,
+    Iterable,
+    Mapping,
+    Optional,
+    Sequence,
+    Tuple,
+    TypeVar,
+    Union,
+    cast,
+)
 from weakref import WeakValueDictionary
 
-from prometheus_client import Gauge
-
 from twisted.internet import defer
 
 from synapse.logging.context import make_deferred_yieldable, preserve_fn
 from synapse.util import unwrapFirstError
-from synapse.util.async_helpers import ObservableDeferred
+from synapse.util.caches.deferred_cache import DeferredCache
 from synapse.util.caches.lrucache import LruCache
-from synapse.util.caches.treecache import TreeCache, iterate_tree_cache_entry
-
-from . import register_cache
 
 logger = logging.getLogger(__name__)
 
@@ -55,241 +61,8 @@ class _CachedFunction(Generic[F]):
     __call__ = None  # type: F
 
 
-cache_pending_metric = Gauge(
-    "synapse_util_caches_cache_pending",
-    "Number of lookups currently pending for this cache",
-    ["name"],
-)
-
-_CacheSentinel = object()
-
-
-class CacheEntry:
-    __slots__ = ["deferred", "callbacks", "invalidated"]
-
-    def __init__(self, deferred, callbacks):
-        self.deferred = deferred
-        self.callbacks = set(callbacks)
-        self.invalidated = False
-
-    def invalidate(self):
-        if not self.invalidated:
-            self.invalidated = True
-            for callback in self.callbacks:
-                callback()
-            self.callbacks.clear()
-
-
-class Cache:
-    __slots__ = (
-        "cache",
-        "name",
-        "keylen",
-        "thread",
-        "metrics",
-        "_pending_deferred_cache",
-    )
-
-    def __init__(
-        self,
-        name: str,
-        max_entries: int = 1000,
-        keylen: int = 1,
-        tree: bool = False,
-        iterable: bool = False,
-        apply_cache_factor_from_config: bool = True,
-    ):
-        """
-        Args:
-            name: The name of the cache
-            max_entries: Maximum amount of entries that the cache will hold
-            keylen: The length of the tuple used as the cache key
-            tree: Use a TreeCache instead of a dict as the underlying cache type
-            iterable: If True, count each item in the cached object as an entry,
-                rather than each cached object
-            apply_cache_factor_from_config: Whether cache factors specified in the
-                config file affect `max_entries`
-
-        Returns:
-            Cache
-        """
-        cache_type = TreeCache if tree else dict
-        self._pending_deferred_cache = cache_type()
-
-        self.cache = LruCache(
-            max_size=max_entries,
-            keylen=keylen,
-            cache_type=cache_type,
-            size_callback=(lambda d: len(d)) if iterable else None,
-            evicted_callback=self._on_evicted,
-            apply_cache_factor_from_config=apply_cache_factor_from_config,
-        )
-
-        self.name = name
-        self.keylen = keylen
-        self.thread = None  # type: Optional[threading.Thread]
-        self.metrics = register_cache(
-            "cache",
-            name,
-            self.cache,
-            collect_callback=self._metrics_collection_callback,
-        )
-
-    @property
-    def max_entries(self):
-        return self.cache.max_size
-
-    def _on_evicted(self, evicted_count):
-        self.metrics.inc_evictions(evicted_count)
-
-    def _metrics_collection_callback(self):
-        cache_pending_metric.labels(self.name).set(len(self._pending_deferred_cache))
-
-    def check_thread(self):
-        expected_thread = self.thread
-        if expected_thread is None:
-            self.thread = threading.current_thread()
-        else:
-            if expected_thread is not threading.current_thread():
-                raise ValueError(
-                    "Cache objects can only be accessed from the main thread"
-                )
-
-    def get(self, key, default=_CacheSentinel, callback=None, update_metrics=True):
-        """Looks the key up in the caches.
-
-        Args:
-            key(tuple)
-            default: What is returned if key is not in the caches. If not
-                specified then function throws KeyError instead
-            callback(fn): Gets called when the entry in the cache is invalidated
-            update_metrics (bool): whether to update the cache hit rate metrics
-
-        Returns:
-            Either an ObservableDeferred or the raw result
-        """
-        callbacks = [callback] if callback else []
-        val = self._pending_deferred_cache.get(key, _CacheSentinel)
-        if val is not _CacheSentinel:
-            val.callbacks.update(callbacks)
-            if update_metrics:
-                self.metrics.inc_hits()
-            return val.deferred
-
-        val = self.cache.get(key, _CacheSentinel, callbacks=callbacks)
-        if val is not _CacheSentinel:
-            self.metrics.inc_hits()
-            return val
-
-        if update_metrics:
-            self.metrics.inc_misses()
-
-        if default is _CacheSentinel:
-            raise KeyError()
-        else:
-            return default
-
-    def set(self, key, value, callback=None):
-        if not isinstance(value, defer.Deferred):
-            raise TypeError("not a Deferred")
-
-        callbacks = [callback] if callback else []
-        self.check_thread()
-        observable = ObservableDeferred(value, consumeErrors=True)
-        observer = observable.observe()
-        entry = CacheEntry(deferred=observable, callbacks=callbacks)
-
-        existing_entry = self._pending_deferred_cache.pop(key, None)
-        if existing_entry:
-            existing_entry.invalidate()
-
-        self._pending_deferred_cache[key] = entry
-
-        def compare_and_pop():
-            """Check if our entry is still the one in _pending_deferred_cache, and
-            if so, pop it.
-
-            Returns true if the entries matched.
-            """
-            existing_entry = self._pending_deferred_cache.pop(key, None)
-            if existing_entry is entry:
-                return True
-
-            # oops, the _pending_deferred_cache has been updated since
-            # we started our query, so we are out of date.
-            #
-            # Better put back whatever we took out. (We do it this way
-            # round, rather than peeking into the _pending_deferred_cache
-            # and then removing on a match, to make the common case faster)
-            if existing_entry is not None:
-                self._pending_deferred_cache[key] = existing_entry
-
-            return False
-
-        def cb(result):
-            if compare_and_pop():
-                self.cache.set(key, result, entry.callbacks)
-            else:
-                # we're not going to put this entry into the cache, so need
-                # to make sure that the invalidation callbacks are called.
-                # That was probably done when _pending_deferred_cache was
-                # updated, but it's possible that `set` was called without
-                # `invalidate` being previously called, in which case it may
-                # not have been. Either way, let's double-check now.
-                entry.invalidate()
-
-        def eb(_fail):
-            compare_and_pop()
-            entry.invalidate()
-
-        # once the deferred completes, we can move the entry from the
-        # _pending_deferred_cache to the real cache.
-        #
-        observer.addCallbacks(cb, eb)
-        return observable
-
-    def prefill(self, key, value, callback=None):
-        callbacks = [callback] if callback else []
-        self.cache.set(key, value, callbacks=callbacks)
-
-    def invalidate(self, key):
-        self.check_thread()
-        self.cache.pop(key, None)
-
-        # if we have a pending lookup for this key, remove it from the
-        # _pending_deferred_cache, which will (a) stop it being returned
-        # for future queries and (b) stop it being persisted as a proper entry
-        # in self.cache.
-        entry = self._pending_deferred_cache.pop(key, None)
-
-        # run the invalidation callbacks now, rather than waiting for the
-        # deferred to resolve.
-        if entry:
-            entry.invalidate()
-
-    def invalidate_many(self, key):
-        self.check_thread()
-        if not isinstance(key, tuple):
-            raise TypeError("The cache key must be a tuple not %r" % (type(key),))
-        self.cache.del_multi(key)
-
-        # if we have a pending lookup for this key, remove it from the
-        # _pending_deferred_cache, as above
-        entry_dict = self._pending_deferred_cache.pop(key, None)
-        if entry_dict is not None:
-            for entry in iterate_tree_cache_entry(entry_dict):
-                entry.invalidate()
-
-    def invalidate_all(self):
-        self.check_thread()
-        self.cache.clear()
-        for entry in self._pending_deferred_cache.values():
-            entry.invalidate()
-        self._pending_deferred_cache.clear()
-
-
 class _CacheDescriptorBase:
-    def __init__(self, orig: _CachedFunction, num_args, cache_context=False):
+    def __init__(self, orig: Callable[..., Any], num_args, cache_context=False):
         self.orig = orig
 
         arg_spec = inspect.getfullargspec(orig)
@@ -338,8 +111,107 @@ class _CacheDescriptorBase:
 
         self.add_cache_context = cache_context
 
+        self.cache_key_builder = get_cache_key_builder(
+            self.arg_names, self.arg_defaults
+        )
 
-class CacheDescriptor(_CacheDescriptorBase):
+
+class _LruCachedFunction(Generic[F]):
+    cache = None  # type: LruCache[CacheKey, Any]
+    __call__ = None  # type: F
+
+
+def lru_cache(
+    max_entries: int = 1000, cache_context: bool = False,
+) -> Callable[[F], _LruCachedFunction[F]]:
+    """A method decorator that applies a memoizing cache around the function.
+
+    This is more-or-less a drop-in equivalent to functools.lru_cache, although note
+    that the signature is slightly different.
+
+    The main differences with functools.lru_cache are:
+        (a) the size of the cache can be controlled via the cache_factor mechanism
+        (b) the wrapped function can request a "cache_context" which provides a
+            callback mechanism to indicate that the result is no longer valid
+        (c) prometheus metrics are exposed automatically.
+
+    The function should take zero or more arguments, which are used as the key for the
+    cache. Single-argument functions use that argument as the cache key; otherwise the
+    arguments are built into a tuple.
+
+    Cached functions can be "chained" (i.e. a cached function can call other cached
+    functions and get appropriately invalidated when they called caches are
+    invalidated) by adding a special "cache_context" argument to the function
+    and passing that as a kwarg to all caches called. For example:
+
+        @lru_cache(cache_context=True)
+        def foo(self, key, cache_context):
+            r1 = self.bar1(key, on_invalidate=cache_context.invalidate)
+            r2 = self.bar2(key, on_invalidate=cache_context.invalidate)
+            return r1 + r2
+
+    The wrapped function also has a 'cache' property which offers direct access to the
+    underlying LruCache.
+    """
+
+    def func(orig: F) -> _LruCachedFunction[F]:
+        desc = LruCacheDescriptor(
+            orig, max_entries=max_entries, cache_context=cache_context,
+        )
+        return cast(_LruCachedFunction[F], desc)
+
+    return func
+
+
+class LruCacheDescriptor(_CacheDescriptorBase):
+    """Helper for @lru_cache"""
+
+    class _Sentinel(enum.Enum):
+        sentinel = object()
+
+    def __init__(
+        self, orig, max_entries: int = 1000, cache_context: bool = False,
+    ):
+        super().__init__(orig, num_args=None, cache_context=cache_context)
+        self.max_entries = max_entries
+
+    def __get__(self, obj, owner):
+        cache = LruCache(
+            cache_name=self.orig.__name__, max_size=self.max_entries,
+        )  # type: LruCache[CacheKey, Any]
+
+        get_cache_key = self.cache_key_builder
+        sentinel = LruCacheDescriptor._Sentinel.sentinel
+
+        @functools.wraps(self.orig)
+        def _wrapped(*args, **kwargs):
+            invalidate_callback = kwargs.pop("on_invalidate", None)
+            callbacks = (invalidate_callback,) if invalidate_callback else ()
+
+            cache_key = get_cache_key(args, kwargs)
+
+            ret = cache.get(cache_key, default=sentinel, callbacks=callbacks)
+            if ret != sentinel:
+                return ret
+
+            # Add our own `cache_context` to argument list if the wrapped function
+            # has asked for one
+            if self.add_cache_context:
+                kwargs["cache_context"] = _CacheContext.get_instance(cache, cache_key)
+
+            ret2 = self.orig(obj, *args, **kwargs)
+            cache.set(cache_key, ret2, callbacks=callbacks)
+
+            return ret2
+
+        wrapped = cast(_CachedFunction, _wrapped)
+        wrapped.cache = cache
+        obj.__dict__[self.orig.__name__] = wrapped
+
+        return wrapped
+
+
+class DeferredCacheDescriptor(_CacheDescriptorBase):
     """ A method decorator that applies a memoizing cache around the function.
 
     This caches deferreds, rather than the results themselves. Deferreds that
@@ -382,7 +254,6 @@ class CacheDescriptor(_CacheDescriptorBase):
         cache_context=False,
         iterable=False,
     ):
-
         super().__init__(orig, num_args=num_args, cache_context=cache_context)
 
         self.max_entries = max_entries
@@ -390,49 +261,15 @@ class CacheDescriptor(_CacheDescriptorBase):
         self.iterable = iterable
 
     def __get__(self, obj, owner):
-        cache = Cache(
+        cache = DeferredCache(
             name=self.orig.__name__,
             max_entries=self.max_entries,
             keylen=self.num_args,
             tree=self.tree,
             iterable=self.iterable,
-        )
+        )  # type: DeferredCache[CacheKey, Any]
 
-        def get_cache_key_gen(args, kwargs):
-            """Given some args/kwargs return a generator that resolves into
-            the cache_key.
-
-            We loop through each arg name, looking up if its in the `kwargs`,
-            otherwise using the next argument in `args`. If there are no more
-            args then we try looking the arg name up in the defaults
-            """
-            pos = 0
-            for nm in self.arg_names:
-                if nm in kwargs:
-                    yield kwargs[nm]
-                elif pos < len(args):
-                    yield args[pos]
-                    pos += 1
-                else:
-                    yield self.arg_defaults[nm]
-
-        # By default our cache key is a tuple, but if there is only one item
-        # then don't bother wrapping in a tuple.  This is to save memory.
-        if self.num_args == 1:
-            nm = self.arg_names[0]
-
-            def get_cache_key(args, kwargs):
-                if nm in kwargs:
-                    return kwargs[nm]
-                elif len(args):
-                    return args[0]
-                else:
-                    return self.arg_defaults[nm]
-
-        else:
-
-            def get_cache_key(args, kwargs):
-                return tuple(get_cache_key_gen(args, kwargs))
+        get_cache_key = self.cache_key_builder
 
         @functools.wraps(self.orig)
         def _wrapped(*args, **kwargs):
@@ -442,32 +279,20 @@ class CacheDescriptor(_CacheDescriptorBase):
 
             cache_key = get_cache_key(args, kwargs)
 
-            # Add our own `cache_context` to argument list if the wrapped function
-            # has asked for one
-            if self.add_cache_context:
-                kwargs["cache_context"] = _CacheContext.get_instance(cache, cache_key)
-
             try:
-                cached_result_d = cache.get(cache_key, callback=invalidate_callback)
-
-                if isinstance(cached_result_d, ObservableDeferred):
-                    observer = cached_result_d.observe()
-                else:
-                    observer = defer.succeed(cached_result_d)
-
+                ret = cache.get(cache_key, callback=invalidate_callback)
             except KeyError:
+                # Add our own `cache_context` to argument list if the wrapped function
+                # has asked for one
+                if self.add_cache_context:
+                    kwargs["cache_context"] = _CacheContext.get_instance(
+                        cache, cache_key
+                    )
+
                 ret = defer.maybeDeferred(preserve_fn(self.orig), obj, *args, **kwargs)
+                ret = cache.set(cache_key, ret, callback=invalidate_callback)
 
-                def onErr(f):
-                    cache.invalidate(cache_key)
-                    return f
-
-                ret.addErrback(onErr)
-
-                result_d = cache.set(cache_key, ret, callback=invalidate_callback)
-                observer = result_d.observe()
-
-            return make_deferred_yieldable(observer)
+            return make_deferred_yieldable(ret)
 
         wrapped = cast(_CachedFunction, _wrapped)
 
@@ -476,7 +301,6 @@ class CacheDescriptor(_CacheDescriptorBase):
             wrapped.prefill = lambda key, val: cache.prefill(key[0], val)
         else:
             wrapped.invalidate = cache.invalidate
-            wrapped.invalidate_all = cache.invalidate_all
             wrapped.invalidate_many = cache.invalidate_many
             wrapped.prefill = cache.prefill
 
@@ -489,7 +313,7 @@ class CacheDescriptor(_CacheDescriptorBase):
         return wrapped
 
 
-class CacheListDescriptor(_CacheDescriptorBase):
+class DeferredCacheListDescriptor(_CacheDescriptorBase):
     """Wraps an existing cache to support bulk fetching of keys.
 
     Given a list of keys it looks in the cache to find any hits, then passes
@@ -526,7 +350,7 @@ class CacheListDescriptor(_CacheDescriptorBase):
 
     def __get__(self, obj, objtype=None):
         cached_method = getattr(obj, self.cached_method_name)
-        cache = cached_method.cache
+        cache = cached_method.cache  # type: DeferredCache[CacheKey, Any]
         num_args = cached_method.num_args
 
         @functools.wraps(self.orig)
@@ -566,14 +390,11 @@ class CacheListDescriptor(_CacheDescriptorBase):
             for arg in list_args:
                 try:
                     res = cache.get(arg_to_cache_key(arg), callback=invalidate_callback)
-                    if not isinstance(res, ObservableDeferred):
-                        results[arg] = res
-                    elif not res.has_succeeded():
-                        res = res.observe()
+                    if not res.called:
                         res.addCallback(update_results_dict, arg)
                         cached_defers.append(res)
                     else:
-                        results[arg] = res.get_result()
+                        results[arg] = res.result
                 except KeyError:
                     missing.add(arg)
 
@@ -638,11 +459,13 @@ class _CacheContext:
     on a lower level.
     """
 
+    Cache = Union[DeferredCache, LruCache]
+
     _cache_context_objects = (
         WeakValueDictionary()
-    )  # type: WeakValueDictionary[Tuple[Cache, CacheKey], _CacheContext]
+    )  # type: WeakValueDictionary[Tuple[_CacheContext.Cache, CacheKey], _CacheContext]
 
-    def __init__(self, cache, cache_key):  # type: (Cache, CacheKey) -> None
+    def __init__(self, cache: "_CacheContext.Cache", cache_key: CacheKey) -> None:
         self._cache = cache
         self._cache_key = cache_key
 
@@ -651,7 +474,9 @@ class _CacheContext:
         self._cache.invalidate(self._cache_key)
 
     @classmethod
-    def get_instance(cls, cache, cache_key):  # type: (Cache, CacheKey) -> _CacheContext
+    def get_instance(
+        cls, cache: "_CacheContext.Cache", cache_key: CacheKey
+    ) -> "_CacheContext":
         """Returns an instance constructed with the given arguments.
 
         A new instance is only created if none already exists.
@@ -672,7 +497,7 @@ def cached(
     cache_context: bool = False,
     iterable: bool = False,
 ) -> Callable[[F], _CachedFunction[F]]:
-    func = lambda orig: CacheDescriptor(
+    func = lambda orig: DeferredCacheDescriptor(
         orig,
         max_entries=max_entries,
         num_args=num_args,
@@ -714,7 +539,7 @@ def cachedList(
             def batch_do_something(self, first_arg, second_args):
                 ...
     """
-    func = lambda orig: CacheListDescriptor(
+    func = lambda orig: DeferredCacheListDescriptor(
         orig,
         cached_method_name=cached_method_name,
         list_name=list_name,
@@ -722,3 +547,65 @@ def cachedList(
     )
 
     return cast(Callable[[F], _CachedFunction[F]], func)
+
+
+def get_cache_key_builder(
+    param_names: Sequence[str], param_defaults: Mapping[str, Any]
+) -> Callable[[Sequence[Any], Mapping[str, Any]], CacheKey]:
+    """Construct a function which will build cache keys suitable for a cached function
+
+    Args:
+        param_names: list of formal parameter names for the cached function
+        param_defaults: a mapping from parameter name to default value for that param
+
+    Returns:
+        A function which will take an (args, kwargs) pair and return a cache key
+    """
+
+    # By default our cache key is a tuple, but if there is only one item
+    # then don't bother wrapping in a tuple.  This is to save memory.
+
+    if len(param_names) == 1:
+        nm = param_names[0]
+
+        def get_cache_key(args: Sequence[Any], kwargs: Mapping[str, Any]) -> CacheKey:
+            if nm in kwargs:
+                return kwargs[nm]
+            elif len(args):
+                return args[0]
+            else:
+                return param_defaults[nm]
+
+    else:
+
+        def get_cache_key(args: Sequence[Any], kwargs: Mapping[str, Any]) -> CacheKey:
+            return tuple(_get_cache_key_gen(param_names, param_defaults, args, kwargs))
+
+    return get_cache_key
+
+
+def _get_cache_key_gen(
+    param_names: Iterable[str],
+    param_defaults: Mapping[str, Any],
+    args: Sequence[Any],
+    kwargs: Mapping[str, Any],
+) -> Iterable[Any]:
+    """Given some args/kwargs return a generator that resolves into
+    the cache_key.
+
+    This is essentially the same operation as `inspect.getcallargs`, but optimised so
+    that we don't need to inspect the target function for each call.
+    """
+
+    # We loop through each arg name, looking up if its in the `kwargs`,
+    # otherwise using the next argument in `args`. If there are no more
+    # args then we try looking the arg name up in the defaults.
+    pos = 0
+    for nm in param_names:
+        if nm in kwargs:
+            yield kwargs[nm]
+        elif pos < len(args):
+            yield args[pos]
+            pos += 1
+        else:
+            yield param_defaults[nm]
diff --git a/synapse/util/caches/dictionary_cache.py b/synapse/util/caches/dictionary_cache.py
index 8592b93689..588d2d49f2 100644
--- a/synapse/util/caches/dictionary_cache.py
+++ b/synapse/util/caches/dictionary_cache.py
@@ -12,15 +12,14 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+import enum
 import logging
 import threading
 from collections import namedtuple
+from typing import Any
 
 from synapse.util.caches.lrucache import LruCache
 
-from . import register_cache
-
 logger = logging.getLogger(__name__)
 
 
@@ -40,24 +39,25 @@ class DictionaryEntry(namedtuple("DictionaryEntry", ("full", "known_absent", "va
         return len(self.value)
 
 
+class _Sentinel(enum.Enum):
+    # defining a sentinel in this way allows mypy to correctly handle the
+    # type of a dictionary lookup.
+    sentinel = object()
+
+
 class DictionaryCache:
     """Caches key -> dictionary lookups, supporting caching partial dicts, i.e.
     fetching a subset of dictionary keys for a particular key.
     """
 
     def __init__(self, name, max_entries=1000):
-        self.cache = LruCache(max_size=max_entries, size_callback=len)
+        self.cache = LruCache(
+            max_size=max_entries, cache_name=name, size_callback=len
+        )  # type: LruCache[Any, DictionaryEntry]
 
         self.name = name
         self.sequence = 0
         self.thread = None
-        # caches_by_name[name] = self.cache
-
-        class Sentinel:
-            __slots__ = []
-
-        self.sentinel = Sentinel()
-        self.metrics = register_cache("dictionary", name, self.cache)
 
     def check_thread(self):
         expected_thread = self.thread
@@ -80,10 +80,8 @@ class DictionaryCache:
         Returns:
             DictionaryEntry
         """
-        entry = self.cache.get(key, self.sentinel)
-        if entry is not self.sentinel:
-            self.metrics.inc_hits()
-
+        entry = self.cache.get(key, _Sentinel.sentinel)
+        if entry is not _Sentinel.sentinel:
             if dict_keys is None:
                 return DictionaryEntry(
                     entry.full, entry.known_absent, dict(entry.value)
@@ -95,7 +93,6 @@ class DictionaryCache:
                     {k: entry.value[k] for k in dict_keys if k in entry.value},
                 )
 
-        self.metrics.inc_misses()
         return DictionaryEntry(False, set(), {})
 
     def invalidate(self, key):
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index 4bc1a67b58..60bb6ff642 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -15,11 +15,35 @@
 
 import threading
 from functools import wraps
-from typing import Callable, Optional, Type, Union
+from typing import (
+    Any,
+    Callable,
+    Generic,
+    Iterable,
+    Optional,
+    Type,
+    TypeVar,
+    Union,
+    cast,
+    overload,
+)
+
+from typing_extensions import Literal
 
 from synapse.config import cache as cache_config
+from synapse.util.caches import CacheMetric, register_cache
 from synapse.util.caches.treecache import TreeCache
 
+# Function type: the type used for invalidation callbacks
+FT = TypeVar("FT", bound=Callable[..., Any])
+
+# Key and Value type for the cache
+KT = TypeVar("KT")
+VT = TypeVar("VT")
+
+# a general type var, distinct from either KT or VT
+T = TypeVar("T")
+
 
 def enumerate_leaves(node, depth):
     if depth == 0:
@@ -41,30 +65,33 @@ class _Node:
         self.callbacks = callbacks
 
 
-class LruCache:
+class LruCache(Generic[KT, VT]):
     """
-    Least-recently-used cache.
+    Least-recently-used cache, supporting prometheus metrics and invalidation callbacks.
+
     Supports del_multi only if cache_type=TreeCache
     If cache_type=TreeCache, all keys must be tuples.
-
-    Can also set callbacks on objects when getting/setting which are fired
-    when that key gets invalidated/evicted.
     """
 
     def __init__(
         self,
         max_size: int,
+        cache_name: Optional[str] = None,
         keylen: int = 1,
         cache_type: Type[Union[dict, TreeCache]] = dict,
         size_callback: Optional[Callable] = None,
-        evicted_callback: Optional[Callable] = None,
+        metrics_collection_callback: Optional[Callable[[], None]] = None,
         apply_cache_factor_from_config: bool = True,
     ):
         """
         Args:
             max_size: The maximum amount of entries the cache can hold
 
-            keylen: The length of the tuple used as the cache key
+            cache_name: The name of this cache, for the prometheus metrics. If unset,
+                no metrics will be reported on this cache.
+
+            keylen: The length of the tuple used as the cache key. Ignored unless
+                cache_type is `TreeCache`.
 
             cache_type (type):
                 type of underlying cache to be used. Typically one of dict
@@ -72,9 +99,13 @@ class LruCache:
 
             size_callback (func(V) -> int | None):
 
-            evicted_callback (func(int)|None):
-                if not None, called on eviction with the size of the evicted
-                entry
+            metrics_collection_callback:
+                metrics collection callback. This is called early in the metrics
+                collection process, before any of the metrics registered with the
+                prometheus Registry are collected, so can be used to update any dynamic
+                metrics.
+
+                Ignored if cache_name is None.
 
             apply_cache_factor_from_config (bool): If true, `max_size` will be
                 multiplied by a cache factor derived from the homeserver config
@@ -93,6 +124,23 @@ class LruCache:
         else:
             self.max_size = int(max_size)
 
+        # register_cache might call our "set_cache_factor" callback; there's nothing to
+        # do yet when we get resized.
+        self._on_resize = None  # type: Optional[Callable[[],None]]
+
+        if cache_name is not None:
+            metrics = register_cache(
+                "lru_cache",
+                cache_name,
+                self,
+                collect_callback=metrics_collection_callback,
+            )  # type: Optional[CacheMetric]
+        else:
+            metrics = None
+
+        # this is exposed for access from outside this class
+        self.metrics = metrics
+
         list_root = _Node(None, None, None, None)
         list_root.next_node = list_root
         list_root.prev_node = list_root
@@ -104,16 +152,16 @@ class LruCache:
                 todelete = list_root.prev_node
                 evicted_len = delete_node(todelete)
                 cache.pop(todelete.key, None)
-                if evicted_callback:
-                    evicted_callback(evicted_len)
+                if metrics:
+                    metrics.inc_evictions(evicted_len)
 
-        def synchronized(f):
+        def synchronized(f: FT) -> FT:
             @wraps(f)
             def inner(*args, **kwargs):
                 with lock:
                     return f(*args, **kwargs)
 
-            return inner
+            return cast(FT, inner)
 
         cached_cache_len = [0]
         if size_callback is not None:
@@ -167,18 +215,45 @@ class LruCache:
             node.callbacks.clear()
             return deleted_len
 
+        @overload
+        def cache_get(
+            key: KT,
+            default: Literal[None] = None,
+            callbacks: Iterable[Callable[[], None]] = ...,
+            update_metrics: bool = ...,
+        ) -> Optional[VT]:
+            ...
+
+        @overload
+        def cache_get(
+            key: KT,
+            default: T,
+            callbacks: Iterable[Callable[[], None]] = ...,
+            update_metrics: bool = ...,
+        ) -> Union[T, VT]:
+            ...
+
         @synchronized
-        def cache_get(key, default=None, callbacks=[]):
+        def cache_get(
+            key: KT,
+            default: Optional[T] = None,
+            callbacks: Iterable[Callable[[], None]] = [],
+            update_metrics: bool = True,
+        ):
             node = cache.get(key, None)
             if node is not None:
                 move_node_to_front(node)
                 node.callbacks.update(callbacks)
+                if update_metrics and metrics:
+                    metrics.inc_hits()
                 return node.value
             else:
+                if update_metrics and metrics:
+                    metrics.inc_misses()
                 return default
 
         @synchronized
-        def cache_set(key, value, callbacks=[]):
+        def cache_set(key: KT, value: VT, callbacks: Iterable[Callable[[], None]] = []):
             node = cache.get(key, None)
             if node is not None:
                 # We sometimes store large objects, e.g. dicts, which cause
@@ -207,7 +282,7 @@ class LruCache:
             evict()
 
         @synchronized
-        def cache_set_default(key, value):
+        def cache_set_default(key: KT, value: VT) -> VT:
             node = cache.get(key, None)
             if node is not None:
                 return node.value
@@ -216,8 +291,16 @@ class LruCache:
                 evict()
                 return value
 
+        @overload
+        def cache_pop(key: KT, default: Literal[None] = None) -> Optional[VT]:
+            ...
+
+        @overload
+        def cache_pop(key: KT, default: T) -> Union[T, VT]:
+            ...
+
         @synchronized
-        def cache_pop(key, default=None):
+        def cache_pop(key: KT, default: Optional[T] = None):
             node = cache.get(key, None)
             if node:
                 delete_node(node)
@@ -227,18 +310,18 @@ class LruCache:
                 return default
 
         @synchronized
-        def cache_del_multi(key):
+        def cache_del_multi(key: KT) -> None:
             """
             This will only work if constructed with cache_type=TreeCache
             """
             popped = cache.pop(key)
             if popped is None:
                 return
-            for leaf in enumerate_leaves(popped, keylen - len(key)):
+            for leaf in enumerate_leaves(popped, keylen - len(cast(tuple, key))):
                 delete_node(leaf)
 
         @synchronized
-        def cache_clear():
+        def cache_clear() -> None:
             list_root.next_node = list_root
             list_root.prev_node = list_root
             for node in cache.values():
@@ -249,15 +332,21 @@ class LruCache:
                 cached_cache_len[0] = 0
 
         @synchronized
-        def cache_contains(key):
+        def cache_contains(key: KT) -> bool:
             return key in cache
 
         self.sentinel = object()
+
+        # make sure that we clear out any excess entries after we get resized.
         self._on_resize = evict
+
         self.get = cache_get
         self.set = cache_set
         self.setdefault = cache_set_default
         self.pop = cache_pop
+        # `invalidate` is exposed for consistency with DeferredCache, so that it can be
+        # invalidated by the cache invalidation replication stream.
+        self.invalidate = cache_pop
         if cache_type is TreeCache:
             self.del_multi = cache_del_multi
         self.len = synchronized(cache_len)
@@ -301,6 +390,7 @@ class LruCache:
         new_size = int(self._original_max_size * factor)
         if new_size != self.max_size:
             self.max_size = new_size
-            self._on_resize()
+            if self._on_resize:
+                self._on_resize()
             return True
         return False
diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py
index df1a721add..32228f42ee 100644
--- a/synapse/util/caches/response_cache.py
+++ b/synapse/util/caches/response_cache.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
+from typing import TYPE_CHECKING, Any, Callable, Dict, Generic, Optional, TypeVar
 
 from twisted.internet import defer
 
@@ -20,10 +21,15 @@ from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.util.async_helpers import ObservableDeferred
 from synapse.util.caches import register_cache
 
+if TYPE_CHECKING:
+    from synapse.app.homeserver import HomeServer
+
 logger = logging.getLogger(__name__)
 
+T = TypeVar("T")
 
-class ResponseCache:
+
+class ResponseCache(Generic[T]):
     """
     This caches a deferred response. Until the deferred completes it will be
     returned from the cache. This means that if the client retries the request
@@ -31,8 +37,9 @@ class ResponseCache:
     used rather than trying to compute a new response.
     """
 
-    def __init__(self, hs, name, timeout_ms=0):
-        self.pending_result_cache = {}  # Requests that haven't finished yet.
+    def __init__(self, hs: "HomeServer", name: str, timeout_ms: float = 0):
+        # Requests that haven't finished yet.
+        self.pending_result_cache = {}  # type: Dict[T, ObservableDeferred]
 
         self.clock = hs.get_clock()
         self.timeout_sec = timeout_ms / 1000.0
@@ -40,13 +47,13 @@ class ResponseCache:
         self._name = name
         self._metrics = register_cache("response_cache", name, self, resizable=False)
 
-    def size(self):
+    def size(self) -> int:
         return len(self.pending_result_cache)
 
-    def __len__(self):
+    def __len__(self) -> int:
         return self.size()
 
-    def get(self, key):
+    def get(self, key: T) -> Optional[defer.Deferred]:
         """Look up the given key.
 
         Can return either a new Deferred (which also doesn't follow the synapse
@@ -58,12 +65,11 @@ class ResponseCache:
         from an absent cache entry.
 
         Args:
-            key (hashable):
+            key: key to get/set in the cache
 
         Returns:
-            twisted.internet.defer.Deferred|None|E: None if there is no entry
-            for this key; otherwise either a deferred result or the result
-            itself.
+            None if there is no entry for this key; otherwise a deferred which
+            resolves to the result.
         """
         result = self.pending_result_cache.get(key)
         if result is not None:
@@ -73,7 +79,7 @@ class ResponseCache:
             self._metrics.inc_misses()
             return None
 
-    def set(self, key, deferred):
+    def set(self, key: T, deferred: defer.Deferred) -> defer.Deferred:
         """Set the entry for the given key to the given deferred.
 
         *deferred* should run its callbacks in the sentinel logcontext (ie,
@@ -85,12 +91,11 @@ class ResponseCache:
         result. You will probably want to make_deferred_yieldable the result.
 
         Args:
-            key (hashable):
-            deferred (twisted.internet.defer.Deferred[T):
+            key: key to get/set in the cache
+            deferred: The deferred which resolves to the result.
 
         Returns:
-            twisted.internet.defer.Deferred[T]|T: a new deferred, or the actual
-                result.
+            A new deferred which resolves to the actual result.
         """
         result = ObservableDeferred(deferred, consumeErrors=True)
         self.pending_result_cache[key] = result
@@ -107,7 +112,9 @@ class ResponseCache:
         result.addBoth(remove)
         return result.observe()
 
-    def wrap(self, key, callback, *args, **kwargs):
+    def wrap(
+        self, key: T, callback: "Callable[..., Any]", *args: Any, **kwargs: Any
+    ) -> defer.Deferred:
         """Wrap together a *get* and *set* call, taking care of logcontexts
 
         First looks up the key in the cache, and if it is present makes it
@@ -118,21 +125,20 @@ class ResponseCache:
 
         Example usage:
 
-            @defer.inlineCallbacks
-            def handle_request(request):
+            async def handle_request(request):
                 # etc
                 return result
 
-            result = yield response_cache.wrap(
+            result = await response_cache.wrap(
                 key,
                 handle_request,
                 request,
             )
 
         Args:
-            key (hashable): key to get/set in the cache
+            key: key to get/set in the cache
 
-            callback (callable): function to call if the key is not found in
+            callback: function to call if the key is not found in
                 the cache
 
             *args: positional parameters to pass to the callback, if it is used
@@ -140,7 +146,7 @@ class ResponseCache:
             **kwargs: named parameters to pass to the callback, if it is used
 
         Returns:
-            twisted.internet.defer.Deferred: yieldable result
+            Deferred which resolves to the result
         """
         result = self.get(key)
         if not result:
diff --git a/synapse/util/caches/ttlcache.py b/synapse/util/caches/ttlcache.py
index 3e180cafd3..6ce2a3d12b 100644
--- a/synapse/util/caches/ttlcache.py
+++ b/synapse/util/caches/ttlcache.py
@@ -34,7 +34,7 @@ class TTLCache:
         self._data = {}
 
         # the _CacheEntries, sorted by expiry time
-        self._expiry_list = SortedList()
+        self._expiry_list = SortedList()  # type: SortedList[_CacheEntry]
 
         self._timer = timer
 
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index bf094c9386..5f7a6dd1d3 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -13,8 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import json
-
 from frozendict import frozendict
 
 
@@ -49,23 +47,3 @@ def unfreeze(o):
         pass
 
     return o
-
-
-def _handle_frozendict(obj):
-    """Helper for EventEncoder. Makes frozendicts serializable by returning
-    the underlying dict
-    """
-    if type(obj) is frozendict:
-        # fishing the protected dict out of the object is a bit nasty,
-        # but we don't really want the overhead of copying the dict.
-        return obj._dict
-    raise TypeError(
-        "Object of type %s is not JSON serializable" % obj.__class__.__name__
-    )
-
-
-# A JSONEncoder which is capable of encoding frozendicts without barfing.
-# Additionally reduce the whitespace produced by JSON encoding.
-frozendict_json_encoder = json.JSONEncoder(
-    allow_nan=False, separators=(",", ":"), default=_handle_frozendict,
-)
diff --git a/synapse/util/module_loader.py b/synapse/util/module_loader.py
index bb62db4637..94b59afb38 100644
--- a/synapse/util/module_loader.py
+++ b/synapse/util/module_loader.py
@@ -36,7 +36,7 @@ def load_module(provider):
     try:
         provider_config = provider_class.parse_config(provider.get("config"))
     except Exception as e:
-        raise ConfigError("Failed to parse config for %r: %r" % (provider["module"], e))
+        raise ConfigError("Failed to parse config for %r: %s" % (provider["module"], e))
 
     return provider_class, provider_config
 
diff --git a/synapse/util/retryutils.py b/synapse/util/retryutils.py
index a5cc9d0551..4ab379e429 100644
--- a/synapse/util/retryutils.py
+++ b/synapse/util/retryutils.py
@@ -110,7 +110,7 @@ async def get_retry_limiter(destination, clock, store, ignore_backoff=False, **k
         failure_ts,
         retry_interval,
         backoff_on_failure=backoff_on_failure,
-        **kwargs
+        **kwargs,
     )
 
 
diff --git a/synapse/visibility.py b/synapse/visibility.py
index e3da7744d2..527365498e 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -16,7 +16,7 @@
 import logging
 import operator
 
-from synapse.api.constants import EventTypes, Membership
+from synapse.api.constants import AccountDataTypes, EventTypes, Membership
 from synapse.events.utils import prune_event
 from synapse.storage import Storage
 from synapse.storage.state import StateFilter
@@ -77,15 +77,14 @@ async def filter_events_for_client(
     )
 
     ignore_dict_content = await storage.main.get_global_account_data_by_type_for_user(
-        "m.ignored_user_list", user_id
+        AccountDataTypes.IGNORED_USER_LIST, user_id
     )
 
-    # FIXME: This will explode if people upload something incorrect.
-    ignore_list = frozenset(
-        ignore_dict_content.get("ignored_users", {}).keys()
-        if ignore_dict_content
-        else []
-    )
+    ignore_list = frozenset()
+    if ignore_dict_content:
+        ignored_users_dict = ignore_dict_content.get("ignored_users", {})
+        if isinstance(ignored_users_dict, dict):
+            ignore_list = frozenset(ignored_users_dict.keys())
 
     erased_senders = await storage.main.are_users_erased((e.sender for e in events))
 
diff --git a/synctl b/synctl
index 9395ebd048..cfa9cec0c4 100755
--- a/synctl
+++ b/synctl
@@ -358,6 +358,13 @@ def main():
         for worker in workers:
             env = os.environ.copy()
 
+            # Skip starting a worker if its already running
+            if os.path.exists(worker.pidfile) and pid_running(
+                int(open(worker.pidfile).read())
+            ):
+                print(worker.app + " already running")
+                continue
+
             if worker.cache_factor:
                 os.environ["SYNAPSE_CACHE_FACTOR"] = str(worker.cache_factor)
 
diff --git a/synmark/__init__.py b/synmark/__init__.py
index 53698bd5ab..3d4ec3e184 100644
--- a/synmark/__init__.py
+++ b/synmark/__init__.py
@@ -15,55 +15,19 @@
 
 import sys
 
-from twisted.internet import epollreactor
+try:
+    from twisted.internet.epollreactor import EPollReactor as Reactor
+except ImportError:
+    from twisted.internet.pollreactor import PollReactor as Reactor
 from twisted.internet.main import installReactor
 
-from synapse.config.homeserver import HomeServerConfig
-from synapse.util import Clock
-
-from tests.utils import default_config, setup_test_homeserver
-
-
-async def make_homeserver(reactor, config=None):
-    """
-    Make a Homeserver suitable for running benchmarks against.
-
-    Args:
-        reactor: A Twisted reactor to run under.
-        config: A HomeServerConfig to use, or None.
-    """
-    cleanup_tasks = []
-    clock = Clock(reactor)
-
-    if not config:
-        config = default_config("test")
-
-    config_obj = HomeServerConfig()
-    config_obj.parse_config_dict(config, "", "")
-
-    hs = await setup_test_homeserver(
-        cleanup_tasks.append, config=config_obj, reactor=reactor, clock=clock
-    )
-    stor = hs.get_datastore()
-
-    # Run the database background updates.
-    if hasattr(stor.db_pool.updates, "do_next_background_update"):
-        while not await stor.db_pool.updates.has_completed_background_updates():
-            await stor.db_pool.updates.do_next_background_update(1)
-
-    def cleanup():
-        for i in cleanup_tasks:
-            i()
-
-    return hs, clock.sleep, cleanup
-
 
 def make_reactor():
     """
     Instantiate and install a Twisted reactor suitable for testing (i.e. not the
     default global one).
     """
-    reactor = epollreactor.EPollReactor()
+    reactor = Reactor()
 
     if "twisted.internet.reactor" in sys.modules:
         del sys.modules["twisted.internet.reactor"]
diff --git a/synmark/__main__.py b/synmark/__main__.py
index 17df9ddeb7..de13c1a909 100644
--- a/synmark/__main__.py
+++ b/synmark/__main__.py
@@ -12,20 +12,20 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import sys
 from argparse import REMAINDER
 from contextlib import redirect_stderr
 from io import StringIO
 
 import pyperf
-from synmark import make_reactor
-from synmark.suites import SUITES
 
 from twisted.internet.defer import Deferred, ensureDeferred
 from twisted.logger import globalLogBeginner, textFileLogObserver
 from twisted.python.failure import Failure
 
+from synmark import make_reactor
+from synmark.suites import SUITES
+
 from tests.utils import setupdb
 
 
diff --git a/synmark/suites/logging.py b/synmark/suites/logging.py
index d8e4c7d58f..c9d9cf761e 100644
--- a/synmark/suites/logging.py
+++ b/synmark/suites/logging.py
@@ -13,20 +13,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
 import warnings
 from io import StringIO
 
 from mock import Mock
 
 from pyperf import perf_counter
-from synmark import make_homeserver
 
 from twisted.internet.defer import Deferred
 from twisted.internet.protocol import ServerFactory
-from twisted.logger import LogBeginner, Logger, LogPublisher
+from twisted.logger import LogBeginner, LogPublisher
 from twisted.protocols.basic import LineOnlyReceiver
 
-from synapse.logging._structured import setup_structured_logging
+from synapse.config.logger import _setup_stdlib_logging
+from synapse.logging import RemoteHandler
+from synapse.util import Clock
 
 
 class LineCounter(LineOnlyReceiver):
@@ -62,7 +64,15 @@ async def main(reactor, loops):
     logger_factory.on_done = Deferred()
     port = reactor.listenTCP(0, logger_factory, interface="127.0.0.1")
 
-    hs, wait, cleanup = await make_homeserver(reactor)
+    # A fake homeserver config.
+    class Config:
+        server_name = "synmark-" + str(loops)
+        no_redirect_stdio = True
+
+    hs_config = Config()
+
+    # To be able to sleep.
+    clock = Clock(reactor)
 
     errors = StringIO()
     publisher = LogPublisher()
@@ -72,47 +82,49 @@ async def main(reactor, loops):
     )
 
     log_config = {
-        "loggers": {"synapse": {"level": "DEBUG"}},
-        "drains": {
+        "version": 1,
+        "loggers": {"synapse": {"level": "DEBUG", "handlers": ["tersejson"]}},
+        "formatters": {"tersejson": {"class": "synapse.logging.TerseJsonFormatter"}},
+        "handlers": {
             "tersejson": {
-                "type": "network_json_terse",
+                "class": "synapse.logging.RemoteHandler",
                 "host": "127.0.0.1",
                 "port": port.getHost().port,
                 "maximum_buffer": 100,
+                "_reactor": reactor,
             }
         },
     }
 
-    logger = Logger(namespace="synapse.logging.test_terse_json", observer=publisher)
-    logging_system = setup_structured_logging(
-        hs, hs.config, log_config, logBeginner=beginner, redirect_stdlib_logging=False
+    logger = logging.getLogger("synapse.logging.test_terse_json")
+    _setup_stdlib_logging(
+        hs_config, log_config, logBeginner=beginner,
     )
 
     # Wait for it to connect...
-    await logging_system._observers[0]._service.whenConnected()
+    for handler in logging.getLogger("synapse").handlers:
+        if isinstance(handler, RemoteHandler):
+            break
+    else:
+        raise RuntimeError("Improperly configured: no RemoteHandler found.")
+
+    await handler._service.whenConnected()
 
     start = perf_counter()
 
     # Send a bunch of useful messages
     for i in range(0, loops):
-        logger.info("test message %s" % (i,))
+        logger.info("test message %s", i)
 
-        if (
-            len(logging_system._observers[0]._buffer)
-            == logging_system._observers[0].maximum_buffer
-        ):
-            while (
-                len(logging_system._observers[0]._buffer)
-                > logging_system._observers[0].maximum_buffer / 2
-            ):
-                await wait(0.01)
+        if len(handler._buffer) == handler.maximum_buffer:
+            while len(handler._buffer) > handler.maximum_buffer / 2:
+                await clock.sleep(0.01)
 
     await logger_factory.on_done
 
     end = perf_counter() - start
 
-    logging_system.stop()
+    handler.close()
     port.stopListening()
-    cleanup()
 
     return end
diff --git a/sytest-blacklist b/sytest-blacklist
index a0e72eb155..9b7161fec1 100644
--- a/sytest-blacklist
+++ b/sytest-blacklist
@@ -34,9 +34,6 @@ New federated private chats get full presence information (SYN-115)
 # this requirement from the spec
 Inbound federation of state requires event_id as a mandatory paramater
 
-# Blacklisted until https://github.com/matrix-org/synapse/pull/6486 lands
-Can upload self-signing keys
-
 # Blacklisted until MSC2753 is implemented
 Local users can peek into world_readable rooms by room ID
 We can't peek into rooms with shared history_visibility
diff --git a/tests/api/test_auth.py b/tests/api/test_auth.py
index 8ab56ec94c..ee5217b074 100644
--- a/tests/api/test_auth.py
+++ b/tests/api/test_auth.py
@@ -19,7 +19,6 @@ import pymacaroons
 
 from twisted.internet import defer
 
-import synapse.handlers.auth
 from synapse.api.auth import Auth
 from synapse.api.constants import UserTypes
 from synapse.api.errors import (
@@ -30,26 +29,22 @@ from synapse.api.errors import (
     MissingClientTokenError,
     ResourceLimitError,
 )
+from synapse.storage.databases.main.registration import TokenLookupResult
 from synapse.types import UserID
 
 from tests import unittest
 from tests.utils import mock_getRawHeaders, setup_test_homeserver
 
 
-class TestHandlers:
-    def __init__(self, hs):
-        self.auth_handler = synapse.handlers.auth.AuthHandler(hs)
-
-
 class AuthTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
         self.state_handler = Mock()
         self.store = Mock()
 
-        self.hs = yield setup_test_homeserver(self.addCleanup, handlers=None)
+        self.hs = yield setup_test_homeserver(self.addCleanup)
         self.hs.get_datastore = Mock(return_value=self.store)
-        self.hs.handlers = TestHandlers(self.hs)
+        self.hs.get_auth_handler().store = self.store
         self.auth = Auth(self.hs)
 
         # AuthBlocking reads from the hs' config on initialization. We need to
@@ -67,7 +62,9 @@ class AuthTestCase(unittest.TestCase):
 
     @defer.inlineCallbacks
     def test_get_user_by_req_user_valid_token(self):
-        user_info = {"name": self.test_user, "token_id": "ditto", "device_id": "device"}
+        user_info = TokenLookupResult(
+            user_id=self.test_user, token_id=5, device_id="device"
+        )
         self.store.get_user_by_access_token = Mock(
             return_value=defer.succeed(user_info)
         )
@@ -90,7 +87,7 @@ class AuthTestCase(unittest.TestCase):
         self.assertEqual(f.errcode, "M_UNKNOWN_TOKEN")
 
     def test_get_user_by_req_user_missing_token(self):
-        user_info = {"name": self.test_user, "token_id": "ditto"}
+        user_info = TokenLookupResult(user_id=self.test_user, token_id=5)
         self.store.get_user_by_access_token = Mock(
             return_value=defer.succeed(user_info)
         )
@@ -227,7 +224,7 @@ class AuthTestCase(unittest.TestCase):
     def test_get_user_from_macaroon(self):
         self.store.get_user_by_access_token = Mock(
             return_value=defer.succeed(
-                {"name": "@baldrick:matrix.org", "device_id": "device"}
+                TokenLookupResult(user_id="@baldrick:matrix.org", device_id="device")
             )
         )
 
@@ -243,12 +240,11 @@ class AuthTestCase(unittest.TestCase):
         user_info = yield defer.ensureDeferred(
             self.auth.get_user_by_access_token(macaroon.serialize())
         )
-        user = user_info["user"]
-        self.assertEqual(UserID.from_string(user_id), user)
+        self.assertEqual(user_id, user_info.user_id)
 
         # TODO: device_id should come from the macaroon, but currently comes
         # from the db.
-        self.assertEqual(user_info["device_id"], "device")
+        self.assertEqual(user_info.device_id, "device")
 
     @defer.inlineCallbacks
     def test_get_guest_user_from_macaroon(self):
@@ -270,10 +266,8 @@ class AuthTestCase(unittest.TestCase):
         user_info = yield defer.ensureDeferred(
             self.auth.get_user_by_access_token(serialized)
         )
-        user = user_info["user"]
-        is_guest = user_info["is_guest"]
-        self.assertEqual(UserID.from_string(user_id), user)
-        self.assertTrue(is_guest)
+        self.assertEqual(user_id, user_info.user_id)
+        self.assertTrue(user_info.is_guest)
         self.store.get_user_by_id.assert_called_with(user_id)
 
     @defer.inlineCallbacks
@@ -283,24 +277,25 @@ class AuthTestCase(unittest.TestCase):
         self.store.get_device = Mock(return_value=defer.succeed(None))
 
         token = yield defer.ensureDeferred(
-            self.hs.handlers.auth_handler.get_access_token_for_user_id(
+            self.hs.get_auth_handler().get_access_token_for_user_id(
                 USER_ID, "DEVICE", valid_until_ms=None
             )
         )
         self.store.add_access_token_to_user.assert_called_with(
-            USER_ID, token, "DEVICE", None
+            user_id=USER_ID,
+            token=token,
+            device_id="DEVICE",
+            valid_until_ms=None,
+            puppets_user_id=None,
         )
 
         def get_user(tok):
             if token != tok:
                 return defer.succeed(None)
             return defer.succeed(
-                {
-                    "name": USER_ID,
-                    "is_guest": False,
-                    "token_id": 1234,
-                    "device_id": "DEVICE",
-                }
+                TokenLookupResult(
+                    user_id=USER_ID, is_guest=False, token_id=1234, device_id="DEVICE",
+                )
             )
 
         self.store.get_user_by_access_token = get_user
diff --git a/tests/api/test_filtering.py b/tests/api/test_filtering.py
index d2d535d23c..c98ae75974 100644
--- a/tests/api/test_filtering.py
+++ b/tests/api/test_filtering.py
@@ -50,10 +50,7 @@ class FilteringTestCase(unittest.TestCase):
         self.mock_http_client.put_json = DeferredMockCallable()
 
         hs = yield setup_test_homeserver(
-            self.addCleanup,
-            handlers=None,
-            http_client=self.mock_http_client,
-            keyring=Mock(),
+            self.addCleanup, http_client=self.mock_http_client, keyring=Mock(),
         )
 
         self.filtering = hs.get_filtering()
diff --git a/tests/api/test_ratelimiting.py b/tests/api/test_ratelimiting.py
index 1e1f30d790..fe504d0869 100644
--- a/tests/api/test_ratelimiting.py
+++ b/tests/api/test_ratelimiting.py
@@ -43,7 +43,7 @@ class TestRatelimiter(unittest.TestCase):
 
     def test_allowed_appservice_ratelimited_via_can_requester_do_action(self):
         appservice = ApplicationService(
-            None, "example.com", id="foo", rate_limited=True,
+            None, "example.com", id="foo", rate_limited=True, sender="@as:example.com",
         )
         as_requester = create_requester("@user:example.com", app_service=appservice)
 
@@ -68,7 +68,7 @@ class TestRatelimiter(unittest.TestCase):
 
     def test_allowed_appservice_via_can_requester_do_action(self):
         appservice = ApplicationService(
-            None, "example.com", id="foo", rate_limited=False,
+            None, "example.com", id="foo", rate_limited=False, sender="@as:example.com",
         )
         as_requester = create_requester("@user:example.com", app_service=appservice)
 
diff --git a/tests/app/test_frontend_proxy.py b/tests/app/test_frontend_proxy.py
index 641093d349..40abe9d72d 100644
--- a/tests/app/test_frontend_proxy.py
+++ b/tests/app/test_frontend_proxy.py
@@ -15,6 +15,7 @@
 
 from synapse.app.generic_worker import GenericWorkerServer
 
+from tests.server import make_request
 from tests.unittest import HomeserverTestCase
 
 
@@ -22,7 +23,7 @@ class FrontendProxyTests(HomeserverTestCase):
     def make_homeserver(self, reactor, clock):
 
         hs = self.setup_test_homeserver(
-            http_client=None, homeserverToUse=GenericWorkerServer
+            http_client=None, homeserver_to_use=GenericWorkerServer
         )
 
         return hs
@@ -55,10 +56,8 @@ class FrontendProxyTests(HomeserverTestCase):
         # Grab the resource from the site that was told to listen
         self.assertEqual(len(self.reactor.tcpServers), 1)
         site = self.reactor.tcpServers[0][1]
-        self.resource = site.resource.children[b"_matrix"].children[b"client"]
 
-        request, channel = self.make_request("PUT", "presence/a/status")
-        self.render(request)
+        _, channel = make_request(self.reactor, site, "PUT", "presence/a/status")
 
         # 400 + unrecognised, because nothing is registered
         self.assertEqual(channel.code, 400)
@@ -77,10 +76,8 @@ class FrontendProxyTests(HomeserverTestCase):
         # Grab the resource from the site that was told to listen
         self.assertEqual(len(self.reactor.tcpServers), 1)
         site = self.reactor.tcpServers[0][1]
-        self.resource = site.resource.children[b"_matrix"].children[b"client"]
 
-        request, channel = self.make_request("PUT", "presence/a/status")
-        self.render(request)
+        _, channel = make_request(self.reactor, site, "PUT", "presence/a/status")
 
         # 401, because the stub servlet still checks authentication
         self.assertEqual(channel.code, 401)
diff --git a/tests/app/test_openid_listener.py b/tests/app/test_openid_listener.py
index 0f016c32eb..ea3be95cf1 100644
--- a/tests/app/test_openid_listener.py
+++ b/tests/app/test_openid_listener.py
@@ -20,13 +20,14 @@ from synapse.app.generic_worker import GenericWorkerServer
 from synapse.app.homeserver import SynapseHomeServer
 from synapse.config.server import parse_listener_def
 
+from tests.server import make_request
 from tests.unittest import HomeserverTestCase
 
 
 class FederationReaderOpenIDListenerTests(HomeserverTestCase):
     def make_homeserver(self, reactor, clock):
         hs = self.setup_test_homeserver(
-            http_client=None, homeserverToUse=GenericWorkerServer
+            http_client=None, homeserver_to_use=GenericWorkerServer
         )
         return hs
 
@@ -66,16 +67,15 @@ class FederationReaderOpenIDListenerTests(HomeserverTestCase):
         # Grab the resource from the site that was told to listen
         site = self.reactor.tcpServers[0][1]
         try:
-            self.resource = site.resource.children[b"_matrix"].children[b"federation"]
+            site.resource.children[b"_matrix"].children[b"federation"]
         except KeyError:
             if expectation == "no_resource":
                 return
             raise
 
-        request, channel = self.make_request(
-            "GET", "/_matrix/federation/v1/openid/userinfo"
+        _, channel = make_request(
+            self.reactor, site, "GET", "/_matrix/federation/v1/openid/userinfo"
         )
-        self.render(request)
 
         self.assertEqual(channel.code, 401)
 
@@ -84,7 +84,7 @@ class FederationReaderOpenIDListenerTests(HomeserverTestCase):
 class SynapseHomeserverOpenIDListenerTests(HomeserverTestCase):
     def make_homeserver(self, reactor, clock):
         hs = self.setup_test_homeserver(
-            http_client=None, homeserverToUse=SynapseHomeServer
+            http_client=None, homeserver_to_use=SynapseHomeServer
         )
         return hs
 
@@ -115,15 +115,14 @@ class SynapseHomeserverOpenIDListenerTests(HomeserverTestCase):
         # Grab the resource from the site that was told to listen
         site = self.reactor.tcpServers[0][1]
         try:
-            self.resource = site.resource.children[b"_matrix"].children[b"federation"]
+            site.resource.children[b"_matrix"].children[b"federation"]
         except KeyError:
             if expectation == "no_resource":
                 return
             raise
 
-        request, channel = self.make_request(
-            "GET", "/_matrix/federation/v1/openid/userinfo"
+        _, channel = make_request(
+            self.reactor, site, "GET", "/_matrix/federation/v1/openid/userinfo"
         )
-        self.render(request)
 
         self.assertEqual(channel.code, 401)
diff --git a/tests/appservice/test_appservice.py b/tests/appservice/test_appservice.py
index 236b608d58..0bffeb1150 100644
--- a/tests/appservice/test_appservice.py
+++ b/tests/appservice/test_appservice.py
@@ -31,6 +31,7 @@ class ApplicationServiceTestCase(unittest.TestCase):
     def setUp(self):
         self.service = ApplicationService(
             id="unique_identifier",
+            sender="@as:test",
             url="some_url",
             token="some_token",
             hostname="matrix.org",  # only used by get_groups_for_user
diff --git a/tests/appservice/test_scheduler.py b/tests/appservice/test_scheduler.py
index 68a4caabbf..97f8cad0dd 100644
--- a/tests/appservice/test_scheduler.py
+++ b/tests/appservice/test_scheduler.py
@@ -60,7 +60,7 @@ class ApplicationServiceSchedulerTransactionCtrlTestCase(unittest.TestCase):
         self.successResultOf(defer.ensureDeferred(self.txnctrl.send(service, events)))
 
         self.store.create_appservice_txn.assert_called_once_with(
-            service=service, events=events  # txn made and saved
+            service=service, events=events, ephemeral=[]  # txn made and saved
         )
         self.assertEquals(0, len(self.txnctrl.recoverers))  # no recoverer made
         txn.complete.assert_called_once_with(self.store)  # txn completed
@@ -81,7 +81,7 @@ class ApplicationServiceSchedulerTransactionCtrlTestCase(unittest.TestCase):
         self.successResultOf(defer.ensureDeferred(self.txnctrl.send(service, events)))
 
         self.store.create_appservice_txn.assert_called_once_with(
-            service=service, events=events  # txn made and saved
+            service=service, events=events, ephemeral=[]  # txn made and saved
         )
         self.assertEquals(0, txn.send.call_count)  # txn not sent though
         self.assertEquals(0, txn.complete.call_count)  # or completed
@@ -106,7 +106,7 @@ class ApplicationServiceSchedulerTransactionCtrlTestCase(unittest.TestCase):
         self.successResultOf(defer.ensureDeferred(self.txnctrl.send(service, events)))
 
         self.store.create_appservice_txn.assert_called_once_with(
-            service=service, events=events
+            service=service, events=events, ephemeral=[]
         )
         self.assertEquals(1, self.recoverer_fn.call_count)  # recoverer made
         self.assertEquals(1, self.recoverer.recover.call_count)  # and invoked
@@ -202,26 +202,28 @@ class ApplicationServiceSchedulerQueuerTestCase(unittest.TestCase):
         # Expect the event to be sent immediately.
         service = Mock(id=4)
         event = Mock()
-        self.queuer.enqueue(service, event)
-        self.txn_ctrl.send.assert_called_once_with(service, [event])
+        self.queuer.enqueue_event(service, event)
+        self.txn_ctrl.send.assert_called_once_with(service, [event], [])
 
     def test_send_single_event_with_queue(self):
         d = defer.Deferred()
-        self.txn_ctrl.send = Mock(side_effect=lambda x, y: make_deferred_yieldable(d))
+        self.txn_ctrl.send = Mock(
+            side_effect=lambda x, y, z: make_deferred_yieldable(d)
+        )
         service = Mock(id=4)
         event = Mock(event_id="first")
         event2 = Mock(event_id="second")
         event3 = Mock(event_id="third")
         # Send an event and don't resolve it just yet.
-        self.queuer.enqueue(service, event)
+        self.queuer.enqueue_event(service, event)
         # Send more events: expect send() to NOT be called multiple times.
-        self.queuer.enqueue(service, event2)
-        self.queuer.enqueue(service, event3)
-        self.txn_ctrl.send.assert_called_with(service, [event])
+        self.queuer.enqueue_event(service, event2)
+        self.queuer.enqueue_event(service, event3)
+        self.txn_ctrl.send.assert_called_with(service, [event], [])
         self.assertEquals(1, self.txn_ctrl.send.call_count)
         # Resolve the send event: expect the queued events to be sent
         d.callback(service)
-        self.txn_ctrl.send.assert_called_with(service, [event2, event3])
+        self.txn_ctrl.send.assert_called_with(service, [event2, event3], [])
         self.assertEquals(2, self.txn_ctrl.send.call_count)
 
     def test_multiple_service_queues(self):
@@ -239,21 +241,99 @@ class ApplicationServiceSchedulerQueuerTestCase(unittest.TestCase):
 
         send_return_list = [srv_1_defer, srv_2_defer]
 
-        def do_send(x, y):
+        def do_send(x, y, z):
             return make_deferred_yieldable(send_return_list.pop(0))
 
         self.txn_ctrl.send = Mock(side_effect=do_send)
 
         # send events for different ASes and make sure they are sent
-        self.queuer.enqueue(srv1, srv_1_event)
-        self.queuer.enqueue(srv1, srv_1_event2)
-        self.txn_ctrl.send.assert_called_with(srv1, [srv_1_event])
-        self.queuer.enqueue(srv2, srv_2_event)
-        self.queuer.enqueue(srv2, srv_2_event2)
-        self.txn_ctrl.send.assert_called_with(srv2, [srv_2_event])
+        self.queuer.enqueue_event(srv1, srv_1_event)
+        self.queuer.enqueue_event(srv1, srv_1_event2)
+        self.txn_ctrl.send.assert_called_with(srv1, [srv_1_event], [])
+        self.queuer.enqueue_event(srv2, srv_2_event)
+        self.queuer.enqueue_event(srv2, srv_2_event2)
+        self.txn_ctrl.send.assert_called_with(srv2, [srv_2_event], [])
 
         # make sure callbacks for a service only send queued events for THAT
         # service
         srv_2_defer.callback(srv2)
-        self.txn_ctrl.send.assert_called_with(srv2, [srv_2_event2])
+        self.txn_ctrl.send.assert_called_with(srv2, [srv_2_event2], [])
         self.assertEquals(3, self.txn_ctrl.send.call_count)
+
+    def test_send_large_txns(self):
+        srv_1_defer = defer.Deferred()
+        srv_2_defer = defer.Deferred()
+        send_return_list = [srv_1_defer, srv_2_defer]
+
+        def do_send(x, y, z):
+            return make_deferred_yieldable(send_return_list.pop(0))
+
+        self.txn_ctrl.send = Mock(side_effect=do_send)
+
+        service = Mock(id=4, name="service")
+        event_list = [Mock(name="event%i" % (i + 1)) for i in range(200)]
+        for event in event_list:
+            self.queuer.enqueue_event(service, event)
+
+        # Expect the first event to be sent immediately.
+        self.txn_ctrl.send.assert_called_with(service, [event_list[0]], [])
+        srv_1_defer.callback(service)
+        # Then send the next 100 events
+        self.txn_ctrl.send.assert_called_with(service, event_list[1:101], [])
+        srv_2_defer.callback(service)
+        # Then the final 99 events
+        self.txn_ctrl.send.assert_called_with(service, event_list[101:], [])
+        self.assertEquals(3, self.txn_ctrl.send.call_count)
+
+    def test_send_single_ephemeral_no_queue(self):
+        # Expect the event to be sent immediately.
+        service = Mock(id=4, name="service")
+        event_list = [Mock(name="event")]
+        self.queuer.enqueue_ephemeral(service, event_list)
+        self.txn_ctrl.send.assert_called_once_with(service, [], event_list)
+
+    def test_send_multiple_ephemeral_no_queue(self):
+        # Expect the event to be sent immediately.
+        service = Mock(id=4, name="service")
+        event_list = [Mock(name="event1"), Mock(name="event2"), Mock(name="event3")]
+        self.queuer.enqueue_ephemeral(service, event_list)
+        self.txn_ctrl.send.assert_called_once_with(service, [], event_list)
+
+    def test_send_single_ephemeral_with_queue(self):
+        d = defer.Deferred()
+        self.txn_ctrl.send = Mock(
+            side_effect=lambda x, y, z: make_deferred_yieldable(d)
+        )
+        service = Mock(id=4)
+        event_list_1 = [Mock(event_id="event1"), Mock(event_id="event2")]
+        event_list_2 = [Mock(event_id="event3"), Mock(event_id="event4")]
+        event_list_3 = [Mock(event_id="event5"), Mock(event_id="event6")]
+
+        # Send an event and don't resolve it just yet.
+        self.queuer.enqueue_ephemeral(service, event_list_1)
+        # Send more events: expect send() to NOT be called multiple times.
+        self.queuer.enqueue_ephemeral(service, event_list_2)
+        self.queuer.enqueue_ephemeral(service, event_list_3)
+        self.txn_ctrl.send.assert_called_with(service, [], event_list_1)
+        self.assertEquals(1, self.txn_ctrl.send.call_count)
+        # Resolve txn_ctrl.send
+        d.callback(service)
+        # Expect the queued events to be sent
+        self.txn_ctrl.send.assert_called_with(service, [], event_list_2 + event_list_3)
+        self.assertEquals(2, self.txn_ctrl.send.call_count)
+
+    def test_send_large_txns_ephemeral(self):
+        d = defer.Deferred()
+        self.txn_ctrl.send = Mock(
+            side_effect=lambda x, y, z: make_deferred_yieldable(d)
+        )
+        # Expect the event to be sent immediately.
+        service = Mock(id=4, name="service")
+        first_chunk = [Mock(name="event%i" % (i + 1)) for i in range(100)]
+        second_chunk = [Mock(name="event%i" % (i + 101)) for i in range(50)]
+        event_list = first_chunk + second_chunk
+        self.queuer.enqueue_ephemeral(service, event_list)
+        self.txn_ctrl.send.assert_called_once_with(service, [], first_chunk)
+        d.callback(service)
+        self.txn_ctrl.send.assert_called_with(service, [], second_chunk)
+        self.assertEquals(2, self.txn_ctrl.send.call_count)
diff --git a/tests/crypto/test_keyring.py b/tests/crypto/test_keyring.py
index 8ff1460c0d..697916a019 100644
--- a/tests/crypto/test_keyring.py
+++ b/tests/crypto/test_keyring.py
@@ -315,7 +315,7 @@ class KeyringTestCase(unittest.HomeserverTestCase):
 class ServerKeyFetcherTestCase(unittest.HomeserverTestCase):
     def make_homeserver(self, reactor, clock):
         self.http_client = Mock()
-        hs = self.setup_test_homeserver(handlers=None, http_client=self.http_client)
+        hs = self.setup_test_homeserver(http_client=self.http_client)
         return hs
 
     def test_get_keys_from_server(self):
@@ -395,9 +395,7 @@ class PerspectivesKeyFetcherTestCase(unittest.HomeserverTestCase):
             }
         ]
 
-        return self.setup_test_homeserver(
-            handlers=None, http_client=self.http_client, config=config
-        )
+        return self.setup_test_homeserver(http_client=self.http_client, config=config)
 
     def build_perspectives_response(
         self, server_name: str, signing_key: SigningKey, valid_until_ts: int,
diff --git a/tests/federation/test_complexity.py b/tests/federation/test_complexity.py
index 1471cc1a28..0187f56e21 100644
--- a/tests/federation/test_complexity.py
+++ b/tests/federation/test_complexity.py
@@ -51,7 +51,6 @@ class RoomComplexityTests(unittest.FederatingHomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/federation/unstable/rooms/%s/complexity" % (room_1,)
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         complexity = channel.json_body["v1"]
         self.assertTrue(complexity > 0, complexity)
@@ -64,7 +63,6 @@ class RoomComplexityTests(unittest.FederatingHomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/federation/unstable/rooms/%s/complexity" % (room_1,)
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         complexity = channel.json_body["v1"]
         self.assertEqual(complexity, 1.23)
diff --git a/tests/federation/test_federation_server.py b/tests/federation/test_federation_server.py
index da933ecd75..3009fbb6c4 100644
--- a/tests/federation/test_federation_server.py
+++ b/tests/federation/test_federation_server.py
@@ -51,7 +51,6 @@ class FederationServerTests(unittest.FederatingHomeserverTestCase):
             "/_matrix/federation/v1/get_missing_events/%s" % (room_1,),
             query_content,
         )
-        self.render(request)
         self.assertEquals(400, channel.code, channel.result)
         self.assertEqual(channel.json_body["errcode"], "M_NOT_JSON")
 
@@ -99,7 +98,6 @@ class StateQueryTests(unittest.FederatingHomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/federation/v1/state/%s" % (room_1,)
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
         self.assertEqual(
@@ -132,7 +130,6 @@ class StateQueryTests(unittest.FederatingHomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/federation/v1/state/%s" % (room_1,)
         )
-        self.render(request)
         self.assertEquals(403, channel.code, channel.result)
         self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
 
diff --git a/tests/federation/transport/test_server.py b/tests/federation/transport/test_server.py
index 72e22d655f..f9e3c7a51f 100644
--- a/tests/federation/transport/test_server.py
+++ b/tests/federation/transport/test_server.py
@@ -40,7 +40,6 @@ class RoomDirectoryFederationTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/federation/v1/publicRooms"
         )
-        self.render(request)
         self.assertEquals(403, channel.code)
 
     @override_config({"allow_public_rooms_over_federation": True})
@@ -48,5 +47,4 @@ class RoomDirectoryFederationTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/federation/v1/publicRooms"
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
diff --git a/tests/handlers/test_admin.py b/tests/handlers/test_admin.py
index fc37c4328c..5c2b4de1a6 100644
--- a/tests/handlers/test_admin.py
+++ b/tests/handlers/test_admin.py
@@ -35,7 +35,7 @@ class ExfiltrateData(unittest.HomeserverTestCase):
     ]
 
     def prepare(self, reactor, clock, hs):
-        self.admin_handler = hs.get_handlers().admin_handler
+        self.admin_handler = hs.get_admin_handler()
 
         self.user1 = self.register_user("user1", "password")
         self.token1 = self.login("user1", "password")
diff --git a/tests/handlers/test_appservice.py b/tests/handlers/test_appservice.py
index 2a0b7c1b56..53763cd0f9 100644
--- a/tests/handlers/test_appservice.py
+++ b/tests/handlers/test_appservice.py
@@ -18,6 +18,7 @@ from mock import Mock
 from twisted.internet import defer
 
 from synapse.handlers.appservice import ApplicationServicesHandler
+from synapse.types import RoomStreamToken
 
 from tests.test_utils import make_awaitable
 from tests.utils import MockClock
@@ -41,7 +42,6 @@ class AppServiceHandlerTestCase(unittest.TestCase):
         hs.get_clock.return_value = MockClock()
         self.handler = ApplicationServicesHandler(hs)
 
-    @defer.inlineCallbacks
     def test_notify_interested_services(self):
         interested_service = self._mkservice(is_interested=True)
         services = [
@@ -61,12 +61,12 @@ class AppServiceHandlerTestCase(unittest.TestCase):
             defer.succeed((0, [event])),
             defer.succeed((0, [])),
         ]
-        yield defer.ensureDeferred(self.handler.notify_interested_services(0))
+        self.handler.notify_interested_services(RoomStreamToken(None, 0))
+
         self.mock_scheduler.submit_event_for_as.assert_called_once_with(
             interested_service, event
         )
 
-    @defer.inlineCallbacks
     def test_query_user_exists_unknown_user(self):
         user_id = "@someone:anywhere"
         services = [self._mkservice(is_interested=True)]
@@ -80,10 +80,11 @@ class AppServiceHandlerTestCase(unittest.TestCase):
             defer.succeed((0, [event])),
             defer.succeed((0, [])),
         ]
-        yield defer.ensureDeferred(self.handler.notify_interested_services(0))
+
+        self.handler.notify_interested_services(RoomStreamToken(None, 0))
+
         self.mock_as_api.query_user.assert_called_once_with(services[0], user_id)
 
-    @defer.inlineCallbacks
     def test_query_user_exists_known_user(self):
         user_id = "@someone:anywhere"
         services = [self._mkservice(is_interested=True)]
@@ -97,7 +98,9 @@ class AppServiceHandlerTestCase(unittest.TestCase):
             defer.succeed((0, [event])),
             defer.succeed((0, [])),
         ]
-        yield defer.ensureDeferred(self.handler.notify_interested_services(0))
+
+        self.handler.notify_interested_services(RoomStreamToken(None, 0))
+
         self.assertFalse(
             self.mock_as_api.query_user.called,
             "query_user called when it shouldn't have been.",
diff --git a/tests/handlers/test_auth.py b/tests/handlers/test_auth.py
index 97877c2e42..e24ce81284 100644
--- a/tests/handlers/test_auth.py
+++ b/tests/handlers/test_auth.py
@@ -21,24 +21,17 @@ from twisted.internet import defer
 import synapse
 import synapse.api.errors
 from synapse.api.errors import ResourceLimitError
-from synapse.handlers.auth import AuthHandler
 
 from tests import unittest
 from tests.test_utils import make_awaitable
 from tests.utils import setup_test_homeserver
 
 
-class AuthHandlers:
-    def __init__(self, hs):
-        self.auth_handler = AuthHandler(hs)
-
-
 class AuthTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
-        self.hs = yield setup_test_homeserver(self.addCleanup, handlers=None)
-        self.hs.handlers = AuthHandlers(self.hs)
-        self.auth_handler = self.hs.handlers.auth_handler
+        self.hs = yield setup_test_homeserver(self.addCleanup)
+        self.auth_handler = self.hs.get_auth_handler()
         self.macaroon_generator = self.hs.get_macaroon_generator()
 
         # MAU tests
@@ -59,7 +52,7 @@ class AuthTestCase(unittest.TestCase):
             self.fail("some_user was not in %s" % macaroon.inspect())
 
     def test_macaroon_caveats(self):
-        self.hs.clock.now = 5000
+        self.hs.get_clock().now = 5000
 
         token = self.macaroon_generator.generate_access_token("a_user")
         macaroon = pymacaroons.Macaroon.deserialize(token)
@@ -85,7 +78,7 @@ class AuthTestCase(unittest.TestCase):
 
     @defer.inlineCallbacks
     def test_short_term_login_token_gives_user_id(self):
-        self.hs.clock.now = 1000
+        self.hs.get_clock().now = 1000
 
         token = self.macaroon_generator.generate_short_term_login_token("a_user", 5000)
         user_id = yield defer.ensureDeferred(
@@ -94,7 +87,7 @@ class AuthTestCase(unittest.TestCase):
         self.assertEqual("a_user", user_id)
 
         # when we advance the clock, the token should be rejected
-        self.hs.clock.now = 6000
+        self.hs.get_clock().now = 6000
         with self.assertRaises(synapse.api.errors.AuthError):
             yield defer.ensureDeferred(
                 self.auth_handler.validate_short_term_login_token_and_get_user_id(token)
diff --git a/tests/handlers/test_device.py b/tests/handlers/test_device.py
index 969d44c787..875aaec2c6 100644
--- a/tests/handlers/test_device.py
+++ b/tests/handlers/test_device.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2016 OpenMarket Ltd
 # Copyright 2018 New Vector Ltd
+# Copyright 2020 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -224,3 +225,84 @@ class DeviceTestCase(unittest.HomeserverTestCase):
                 )
             )
             self.reactor.advance(1000)
+
+
+class DehydrationTestCase(unittest.HomeserverTestCase):
+    def make_homeserver(self, reactor, clock):
+        hs = self.setup_test_homeserver("server", http_client=None)
+        self.handler = hs.get_device_handler()
+        self.registration = hs.get_registration_handler()
+        self.auth = hs.get_auth()
+        self.store = hs.get_datastore()
+        return hs
+
+    def test_dehydrate_and_rehydrate_device(self):
+        user_id = "@boris:dehydration"
+
+        self.get_success(self.store.register_user(user_id, "foobar"))
+
+        # First check if we can store and fetch a dehydrated device
+        stored_dehydrated_device_id = self.get_success(
+            self.handler.store_dehydrated_device(
+                user_id=user_id,
+                device_data={"device_data": {"foo": "bar"}},
+                initial_device_display_name="dehydrated device",
+            )
+        )
+
+        retrieved_device_id, device_data = self.get_success(
+            self.handler.get_dehydrated_device(user_id=user_id)
+        )
+
+        self.assertEqual(retrieved_device_id, stored_dehydrated_device_id)
+        self.assertEqual(device_data, {"device_data": {"foo": "bar"}})
+
+        # Create a new login for the user and dehydrated the device
+        device_id, access_token = self.get_success(
+            self.registration.register_device(
+                user_id=user_id, device_id=None, initial_display_name="new device",
+            )
+        )
+
+        # Trying to claim a nonexistent device should throw an error
+        self.get_failure(
+            self.handler.rehydrate_device(
+                user_id=user_id,
+                access_token=access_token,
+                device_id="not the right device ID",
+            ),
+            synapse.api.errors.NotFoundError,
+        )
+
+        # dehydrating the right devices should succeed and change our device ID
+        # to the dehydrated device's ID
+        res = self.get_success(
+            self.handler.rehydrate_device(
+                user_id=user_id,
+                access_token=access_token,
+                device_id=retrieved_device_id,
+            )
+        )
+
+        self.assertEqual(res, {"success": True})
+
+        # make sure that our device ID has changed
+        user_info = self.get_success(self.auth.get_user_by_access_token(access_token))
+
+        self.assertEqual(user_info.device_id, retrieved_device_id)
+
+        # make sure the device has the display name that was set from the login
+        res = self.get_success(self.handler.get_device(user_id, retrieved_device_id))
+
+        self.assertEqual(res["display_name"], "new device")
+
+        # make sure that the device ID that we were initially assigned no longer exists
+        self.get_failure(
+            self.handler.get_device(user_id, device_id),
+            synapse.api.errors.NotFoundError,
+        )
+
+        # make sure that there's no device available for dehydrating now
+        ret = self.get_success(self.handler.get_dehydrated_device(user_id=user_id))
+
+        self.assertIsNone(ret)
diff --git a/tests/handlers/test_directory.py b/tests/handlers/test_directory.py
index bc0c5aefdc..ee6ef5e6fa 100644
--- a/tests/handlers/test_directory.py
+++ b/tests/handlers/test_directory.py
@@ -48,7 +48,7 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
             federation_registry=self.mock_registry,
         )
 
-        self.handler = hs.get_handlers().directory_handler
+        self.handler = hs.get_directory_handler()
 
         self.store = hs.get_datastore()
 
@@ -110,7 +110,7 @@ class TestCreateAlias(unittest.HomeserverTestCase):
     ]
 
     def prepare(self, reactor, clock, hs):
-        self.handler = hs.get_handlers().directory_handler
+        self.handler = hs.get_directory_handler()
 
         # Create user
         self.admin_user = self.register_user("admin", "pass", admin=True)
@@ -173,7 +173,7 @@ class TestDeleteAlias(unittest.HomeserverTestCase):
 
     def prepare(self, reactor, clock, hs):
         self.store = hs.get_datastore()
-        self.handler = hs.get_handlers().directory_handler
+        self.handler = hs.get_directory_handler()
         self.state_handler = hs.get_state_handler()
 
         # Create user
@@ -289,7 +289,7 @@ class CanonicalAliasTestCase(unittest.HomeserverTestCase):
 
     def prepare(self, reactor, clock, hs):
         self.store = hs.get_datastore()
-        self.handler = hs.get_handlers().directory_handler
+        self.handler = hs.get_directory_handler()
         self.state_handler = hs.get_state_handler()
 
         # Create user
@@ -412,7 +412,6 @@ class TestCreateAliasACL(unittest.HomeserverTestCase):
             b"directory/room/%23test%3Atest",
             ('{"room_id":"%s"}' % (room_id,)).encode("ascii"),
         )
-        self.render(request)
         self.assertEquals(403, channel.code, channel.result)
 
     def test_allowed(self):
@@ -423,7 +422,6 @@ class TestCreateAliasACL(unittest.HomeserverTestCase):
             b"directory/room/%23unofficial_test%3Atest",
             ('{"room_id":"%s"}' % (room_id,)).encode("ascii"),
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
 
@@ -438,11 +436,10 @@ class TestRoomListSearchDisabled(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", b"directory/list/room/%s" % (room_id.encode("ascii"),), b"{}"
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
         self.room_list_handler = hs.get_room_list_handler()
-        self.directory_handler = hs.get_handlers().directory_handler
+        self.directory_handler = hs.get_directory_handler()
 
         return hs
 
@@ -452,7 +449,6 @@ class TestRoomListSearchDisabled(unittest.HomeserverTestCase):
 
         # Room list is enabled so we should get some results
         request, channel = self.make_request("GET", b"publicRooms")
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
         self.assertTrue(len(channel.json_body["chunk"]) > 0)
 
@@ -461,7 +457,6 @@ class TestRoomListSearchDisabled(unittest.HomeserverTestCase):
 
         # Room list disabled so we should get no results
         request, channel = self.make_request("GET", b"publicRooms")
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
         self.assertTrue(len(channel.json_body["chunk"]) == 0)
 
@@ -470,5 +465,4 @@ class TestRoomListSearchDisabled(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", b"directory/list/room/%s" % (room_id.encode("ascii"),), b"{}"
         )
-        self.render(request)
         self.assertEquals(403, channel.code, channel.result)
diff --git a/tests/handlers/test_e2e_keys.py b/tests/handlers/test_e2e_keys.py
index 366dcfb670..924f29f051 100644
--- a/tests/handlers/test_e2e_keys.py
+++ b/tests/handlers/test_e2e_keys.py
@@ -33,13 +33,15 @@ class E2eKeysHandlerTestCase(unittest.TestCase):
         super().__init__(*args, **kwargs)
         self.hs = None  # type: synapse.server.HomeServer
         self.handler = None  # type: synapse.handlers.e2e_keys.E2eKeysHandler
+        self.store = None  # type: synapse.storage.Storage
 
     @defer.inlineCallbacks
     def setUp(self):
         self.hs = yield utils.setup_test_homeserver(
-            self.addCleanup, handlers=None, federation_client=mock.Mock()
+            self.addCleanup, federation_client=mock.Mock()
         )
         self.handler = synapse.handlers.e2e_keys.E2eKeysHandler(self.hs)
+        self.store = self.hs.get_datastore()
 
     @defer.inlineCallbacks
     def test_query_local_devices_no_devices(self):
@@ -171,6 +173,89 @@ class E2eKeysHandlerTestCase(unittest.TestCase):
             },
         )
 
+    @defer.inlineCallbacks
+    def test_fallback_key(self):
+        local_user = "@boris:" + self.hs.hostname
+        device_id = "xyz"
+        fallback_key = {"alg1:k1": "key1"}
+        otk = {"alg1:k2": "key2"}
+
+        # we shouldn't have any unused fallback keys yet
+        res = yield defer.ensureDeferred(
+            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
+        )
+        self.assertEqual(res, [])
+
+        yield defer.ensureDeferred(
+            self.handler.upload_keys_for_user(
+                local_user,
+                device_id,
+                {"org.matrix.msc2732.fallback_keys": fallback_key},
+            )
+        )
+
+        # we should now have an unused alg1 key
+        res = yield defer.ensureDeferred(
+            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
+        )
+        self.assertEqual(res, ["alg1"])
+
+        # claiming an OTK when no OTKs are available should return the fallback
+        # key
+        res = yield defer.ensureDeferred(
+            self.handler.claim_one_time_keys(
+                {"one_time_keys": {local_user: {device_id: "alg1"}}}, timeout=None
+            )
+        )
+        self.assertEqual(
+            res,
+            {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key}}},
+        )
+
+        # we shouldn't have any unused fallback keys again
+        res = yield defer.ensureDeferred(
+            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
+        )
+        self.assertEqual(res, [])
+
+        # claiming an OTK again should return the same fallback key
+        res = yield defer.ensureDeferred(
+            self.handler.claim_one_time_keys(
+                {"one_time_keys": {local_user: {device_id: "alg1"}}}, timeout=None
+            )
+        )
+        self.assertEqual(
+            res,
+            {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key}}},
+        )
+
+        # if the user uploads a one-time key, the next claim should fetch the
+        # one-time key, and then go back to the fallback
+        yield defer.ensureDeferred(
+            self.handler.upload_keys_for_user(
+                local_user, device_id, {"one_time_keys": otk}
+            )
+        )
+
+        res = yield defer.ensureDeferred(
+            self.handler.claim_one_time_keys(
+                {"one_time_keys": {local_user: {device_id: "alg1"}}}, timeout=None
+            )
+        )
+        self.assertEqual(
+            res, {"failures": {}, "one_time_keys": {local_user: {device_id: otk}}},
+        )
+
+        res = yield defer.ensureDeferred(
+            self.handler.claim_one_time_keys(
+                {"one_time_keys": {local_user: {device_id: "alg1"}}}, timeout=None
+            )
+        )
+        self.assertEqual(
+            res,
+            {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key}}},
+        )
+
     @defer.inlineCallbacks
     def test_replace_master_key(self):
         """uploading a new signing key should make the old signing key unavailable"""
diff --git a/tests/handlers/test_e2e_room_keys.py b/tests/handlers/test_e2e_room_keys.py
index 7adde9b9de..45f201a399 100644
--- a/tests/handlers/test_e2e_room_keys.py
+++ b/tests/handlers/test_e2e_room_keys.py
@@ -54,7 +54,7 @@ class E2eRoomKeysHandlerTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def setUp(self):
         self.hs = yield utils.setup_test_homeserver(
-            self.addCleanup, handlers=None, replication_layer=mock.Mock()
+            self.addCleanup, replication_layer=mock.Mock()
         )
         self.handler = synapse.handlers.e2e_room_keys.E2eRoomKeysHandler(self.hs)
         self.local_user = "@boris:" + self.hs.hostname
diff --git a/tests/handlers/test_federation.py b/tests/handlers/test_federation.py
index 96fea58673..bf866dacf3 100644
--- a/tests/handlers/test_federation.py
+++ b/tests/handlers/test_federation.py
@@ -38,7 +38,7 @@ class FederationTestCase(unittest.HomeserverTestCase):
 
     def make_homeserver(self, reactor, clock):
         hs = self.setup_test_homeserver(http_client=None)
-        self.handler = hs.get_handlers().federation_handler
+        self.handler = hs.get_federation_handler()
         self.store = hs.get_datastore()
         return hs
 
@@ -59,7 +59,6 @@ class FederationTestCase(unittest.HomeserverTestCase):
         )
 
         d = self.handler.on_exchange_third_party_invite_request(
-            room_id=room_id,
             event_dict={
                 "type": EventTypes.Member,
                 "room_id": room_id,
diff --git a/tests/handlers/test_identity.py b/tests/handlers/test_identity.py
index 0ab0356109..b7d340bcb8 100644
--- a/tests/handlers/test_identity.py
+++ b/tests/handlers/test_identity.py
@@ -63,7 +63,7 @@ class ThreepidISRewrittenURLTestCase(unittest.HomeserverTestCase):
         # TODO: This class does not use a singleton to get it's http client
         # This should be fixed for easier testing
         # https://github.com/matrix-org/synapse-dinsic/issues/26
-        self.hs.get_handlers().identity_handler.blacklisting_http_client = (
+        self.hs.get_identity_handler().blacklisting_http_client = (
             mock_blacklisting_http_client
         )
 
@@ -79,7 +79,7 @@ class ThreepidISRewrittenURLTestCase(unittest.HomeserverTestCase):
         * the bind request is done against the rewritten hostname
         * the original, non-rewritten, server name is stored in the database
         """
-        handler = self.hs.get_handlers().identity_handler
+        handler = self.hs.get_identity_handler()
         post_json_get_json = handler.blacklisting_http_client.post_json_get_json
         store = self.hs.get_datastore()
 
diff --git a/tests/handlers/test_message.py b/tests/handlers/test_message.py
new file mode 100644
index 0000000000..af42775815
--- /dev/null
+++ b/tests/handlers/test_message.py
@@ -0,0 +1,212 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+from typing import Tuple
+
+from synapse.api.constants import EventTypes
+from synapse.events import EventBase
+from synapse.events.snapshot import EventContext
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
+from synapse.types import create_requester
+from synapse.util.stringutils import random_string
+
+from tests import unittest
+
+logger = logging.getLogger(__name__)
+
+
+class EventCreationTestCase(unittest.HomeserverTestCase):
+    servlets = [
+        admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.handler = self.hs.get_event_creation_handler()
+        self.persist_event_storage = self.hs.get_storage().persistence
+
+        self.user_id = self.register_user("tester", "foobar")
+        self.access_token = self.login("tester", "foobar")
+        self.room_id = self.helper.create_room_as(self.user_id, tok=self.access_token)
+
+        self.info = self.get_success(
+            self.hs.get_datastore().get_user_by_access_token(self.access_token,)
+        )
+        self.token_id = self.info.token_id
+
+        self.requester = create_requester(self.user_id, access_token_id=self.token_id)
+
+    def _create_duplicate_event(self, txn_id: str) -> Tuple[EventBase, EventContext]:
+        """Create a new event with the given transaction ID. All events produced
+        by this method will be considered duplicates.
+        """
+
+        # We create a new event with a random body, as otherwise we'll produce
+        # *exactly* the same event with the same hash, and so same event ID.
+        return self.get_success(
+            self.handler.create_event(
+                self.requester,
+                {
+                    "type": EventTypes.Message,
+                    "room_id": self.room_id,
+                    "sender": self.requester.user.to_string(),
+                    "content": {"msgtype": "m.text", "body": random_string(5)},
+                },
+                txn_id=txn_id,
+            )
+        )
+
+    def test_duplicated_txn_id(self):
+        """Test that attempting to handle/persist an event with a transaction ID
+        that has already been persisted correctly returns the old event and does
+        *not* produce duplicate messages.
+        """
+
+        txn_id = "something_suitably_random"
+
+        event1, context = self._create_duplicate_event(txn_id)
+
+        ret_event1 = self.get_success(
+            self.handler.handle_new_client_event(self.requester, event1, context)
+        )
+        stream_id1 = ret_event1.internal_metadata.stream_ordering
+
+        self.assertEqual(event1.event_id, ret_event1.event_id)
+
+        event2, context = self._create_duplicate_event(txn_id)
+
+        # We want to test that the deduplication at the persit event end works,
+        # so we want to make sure we test with different events.
+        self.assertNotEqual(event1.event_id, event2.event_id)
+
+        ret_event2 = self.get_success(
+            self.handler.handle_new_client_event(self.requester, event2, context)
+        )
+        stream_id2 = ret_event2.internal_metadata.stream_ordering
+
+        # Assert that the returned values match those from the initial event
+        # rather than the new one.
+        self.assertEqual(ret_event1.event_id, ret_event2.event_id)
+        self.assertEqual(stream_id1, stream_id2)
+
+        # Let's test that calling `persist_event` directly also does the right
+        # thing.
+        event3, context = self._create_duplicate_event(txn_id)
+        self.assertNotEqual(event1.event_id, event3.event_id)
+
+        ret_event3, event_pos3, _ = self.get_success(
+            self.persist_event_storage.persist_event(event3, context)
+        )
+
+        # Assert that the returned values match those from the initial event
+        # rather than the new one.
+        self.assertEqual(ret_event1.event_id, ret_event3.event_id)
+        self.assertEqual(stream_id1, event_pos3.stream)
+
+        # Let's test that calling `persist_events` directly also does the right
+        # thing.
+        event4, context = self._create_duplicate_event(txn_id)
+        self.assertNotEqual(event1.event_id, event3.event_id)
+
+        events, _ = self.get_success(
+            self.persist_event_storage.persist_events([(event3, context)])
+        )
+        ret_event4 = events[0]
+
+        # Assert that the returned values match those from the initial event
+        # rather than the new one.
+        self.assertEqual(ret_event1.event_id, ret_event4.event_id)
+
+    def test_duplicated_txn_id_one_call(self):
+        """Test that we correctly handle duplicates that we try and persist at
+        the same time.
+        """
+
+        txn_id = "something_else_suitably_random"
+
+        # Create two duplicate events to persist at the same time
+        event1, context1 = self._create_duplicate_event(txn_id)
+        event2, context2 = self._create_duplicate_event(txn_id)
+
+        # Ensure their event IDs are different to start with
+        self.assertNotEqual(event1.event_id, event2.event_id)
+
+        events, _ = self.get_success(
+            self.persist_event_storage.persist_events(
+                [(event1, context1), (event2, context2)]
+            )
+        )
+
+        # Check that we've deduplicated the events.
+        self.assertEqual(len(events), 2)
+        self.assertEqual(events[0].event_id, events[1].event_id)
+
+
+class ServerAclValidationTestCase(unittest.HomeserverTestCase):
+    servlets = [
+        admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.user_id = self.register_user("tester", "foobar")
+        self.access_token = self.login("tester", "foobar")
+        self.room_id = self.helper.create_room_as(self.user_id, tok=self.access_token)
+
+    def test_allow_server_acl(self):
+        """Test that sending an ACL that blocks everyone but ourselves works.
+        """
+
+        self.helper.send_state(
+            self.room_id,
+            EventTypes.ServerACL,
+            body={"allow": [self.hs.hostname]},
+            tok=self.access_token,
+            expect_code=200,
+        )
+
+    def test_deny_server_acl_block_outselves(self):
+        """Test that sending an ACL that blocks ourselves does not work.
+        """
+        self.helper.send_state(
+            self.room_id,
+            EventTypes.ServerACL,
+            body={},
+            tok=self.access_token,
+            expect_code=400,
+        )
+
+    def test_deny_redact_server_acl(self):
+        """Test that attempting to redact an ACL is blocked.
+        """
+
+        body = self.helper.send_state(
+            self.room_id,
+            EventTypes.ServerACL,
+            body={"allow": [self.hs.hostname]},
+            tok=self.access_token,
+            expect_code=200,
+        )
+        event_id = body["event_id"]
+
+        # Redaction of event should fail.
+        path = "/_matrix/client/r0/rooms/%s/redact/%s" % (self.room_id, event_id)
+        request, channel = self.make_request(
+            "POST", path, content={}, access_token=self.access_token
+        )
+        self.assertEqual(int(channel.result["code"]), 403)
diff --git a/tests/handlers/test_oidc.py b/tests/handlers/test_oidc.py
index d5087e58be..a308c46da9 100644
--- a/tests/handlers/test_oidc.py
+++ b/tests/handlers/test_oidc.py
@@ -12,7 +12,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import json
 from urllib.parse import parse_qs, urlparse
 
@@ -24,12 +23,8 @@ import pymacaroons
 from twisted.python.failure import Failure
 from twisted.web._newclient import ResponseDone
 
-from synapse.handlers.oidc_handler import (
-    MappingException,
-    OidcError,
-    OidcHandler,
-    OidcMappingProvider,
-)
+from synapse.handlers.oidc_handler import OidcError, OidcMappingProvider
+from synapse.handlers.sso import MappingException
 from synapse.types import UserID
 
 from tests.unittest import HomeserverTestCase, override_config
@@ -94,6 +89,14 @@ class TestMappingProviderExtra(TestMappingProvider):
         return {"phone": userinfo["phone"]}
 
 
+class TestMappingProviderFailures(TestMappingProvider):
+    async def map_user_attributes(self, userinfo, token, failures):
+        return {
+            "localpart": userinfo["username"] + (str(failures) if failures else ""),
+            "display_name": None,
+        }
+
+
 def simple_async_mock(return_value=None, raises=None):
     # AsyncMock is not available in python3.5, this mimics part of its behaviour
     async def cb(*args, **kwargs):
@@ -124,22 +127,16 @@ async def get_json(url):
 
 
 class OidcHandlerTestCase(HomeserverTestCase):
-    def make_homeserver(self, reactor, clock):
-
-        self.http_client = Mock(spec=["get_json"])
-        self.http_client.get_json.side_effect = get_json
-        self.http_client.user_agent = "Synapse Test"
-
-        config = self.default_config()
+    def default_config(self):
+        config = super().default_config()
         config["public_baseurl"] = BASE_URL
-        oidc_config = {}
-        oidc_config["enabled"] = True
-        oidc_config["client_id"] = CLIENT_ID
-        oidc_config["client_secret"] = CLIENT_SECRET
-        oidc_config["issuer"] = ISSUER
-        oidc_config["scopes"] = SCOPES
-        oidc_config["user_mapping_provider"] = {
-            "module": __name__ + ".TestMappingProvider",
+        oidc_config = {
+            "enabled": True,
+            "client_id": CLIENT_ID,
+            "client_secret": CLIENT_SECRET,
+            "issuer": ISSUER,
+            "scopes": SCOPES,
+            "user_mapping_provider": {"module": __name__ + ".TestMappingProvider"},
         }
 
         # Update this config with what's in the default config so that
@@ -147,13 +144,24 @@ class OidcHandlerTestCase(HomeserverTestCase):
         oidc_config.update(config.get("oidc_config", {}))
         config["oidc_config"] = oidc_config
 
-        hs = self.setup_test_homeserver(
-            http_client=self.http_client,
-            proxied_http_client=self.http_client,
-            config=config,
-        )
+        return config
 
-        self.handler = OidcHandler(hs)
+    def make_homeserver(self, reactor, clock):
+
+        self.http_client = Mock(spec=["get_json"])
+        self.http_client.get_json.side_effect = get_json
+        self.http_client.user_agent = "Synapse Test"
+
+        hs = self.setup_test_homeserver(proxied_http_client=self.http_client)
+
+        self.handler = hs.get_oidc_handler()
+        sso_handler = hs.get_sso_handler()
+        # Mock the render error method.
+        self.render_error = Mock(return_value=None)
+        sso_handler.render_error = self.render_error
+
+        # Reduce the number of attempts when generating MXIDs.
+        sso_handler._MAP_USERNAME_RETRIES = 3
 
         return hs
 
@@ -161,12 +169,12 @@ class OidcHandlerTestCase(HomeserverTestCase):
         return patch.dict(self.handler._provider_metadata, values)
 
     def assertRenderedError(self, error, error_description=None):
-        args = self.handler._render_error.call_args[0]
+        args = self.render_error.call_args[0]
         self.assertEqual(args[1], error)
         if error_description is not None:
             self.assertEqual(args[2], error_description)
         # Reset the render_error mock
-        self.handler._render_error.reset_mock()
+        self.render_error.reset_mock()
 
     def test_config(self):
         """Basic config correctly sets up the callback URL and client auth correctly."""
@@ -286,9 +294,15 @@ class OidcHandlerTestCase(HomeserverTestCase):
                 h._validate_metadata,
             )
 
-        # Tests for configs that the userinfo endpoint
+        # Tests for configs that require the userinfo endpoint
         self.assertFalse(h._uses_userinfo)
-        h._scopes = []  # do not request the openid scope
+        self.assertEqual(h._user_profile_method, "auto")
+        h._user_profile_method = "userinfo_endpoint"
+        self.assertTrue(h._uses_userinfo)
+
+        # Revert the profile method and do not request the "openid" scope.
+        h._user_profile_method = "auto"
+        h._scopes = []
         self.assertTrue(h._uses_userinfo)
         self.assertRaisesRegex(ValueError, "userinfo_endpoint", h._validate_metadata)
 
@@ -350,7 +364,6 @@ class OidcHandlerTestCase(HomeserverTestCase):
 
     def test_callback_error(self):
         """Errors from the provider returned in the callback are displayed."""
-        self.handler._render_error = Mock()
         request = Mock(args={})
         request.args[b"error"] = [b"invalid_client"]
         self.get_success(self.handler.handle_oidc_callback(request))
@@ -381,14 +394,20 @@ class OidcHandlerTestCase(HomeserverTestCase):
             "preferred_username": "bar",
         }
         user_id = "@foo:domain.org"
-        self.handler._render_error = Mock(return_value=None)
         self.handler._exchange_code = simple_async_mock(return_value=token)
         self.handler._parse_id_token = simple_async_mock(return_value=userinfo)
         self.handler._fetch_userinfo = simple_async_mock(return_value=userinfo)
         self.handler._map_userinfo_to_user = simple_async_mock(return_value=user_id)
         self.handler._auth_handler.complete_sso_login = simple_async_mock()
         request = Mock(
-            spec=["args", "getCookie", "addCookie", "requestHeaders", "getClientIP"]
+            spec=[
+                "args",
+                "getCookie",
+                "addCookie",
+                "requestHeaders",
+                "getClientIP",
+                "get_user_agent",
+            ]
         )
 
         code = "code"
@@ -408,9 +427,8 @@ class OidcHandlerTestCase(HomeserverTestCase):
         request.args[b"code"] = [code.encode("utf-8")]
         request.args[b"state"] = [state.encode("utf-8")]
 
-        request.requestHeaders = Mock(spec=["getRawHeaders"])
-        request.requestHeaders.getRawHeaders.return_value = [user_agent.encode("ascii")]
         request.getClientIP.return_value = ip_address
+        request.get_user_agent.return_value = user_agent
 
         self.get_success(self.handler.handle_oidc_callback(request))
 
@@ -423,7 +441,7 @@ class OidcHandlerTestCase(HomeserverTestCase):
             userinfo, token, user_agent, ip_address
         )
         self.handler._fetch_userinfo.assert_not_called()
-        self.handler._render_error.assert_not_called()
+        self.render_error.assert_not_called()
 
         # Handle mapping errors
         self.handler._map_userinfo_to_user = simple_async_mock(
@@ -457,7 +475,7 @@ class OidcHandlerTestCase(HomeserverTestCase):
             userinfo, token, user_agent, ip_address
         )
         self.handler._fetch_userinfo.assert_called_once_with(token)
-        self.handler._render_error.assert_not_called()
+        self.render_error.assert_not_called()
 
         # Handle userinfo fetching error
         self.handler._fetch_userinfo = simple_async_mock(raises=Exception())
@@ -473,7 +491,6 @@ class OidcHandlerTestCase(HomeserverTestCase):
 
     def test_callback_session(self):
         """The callback verifies the session presence and validity"""
-        self.handler._render_error = Mock(return_value=None)
         request = Mock(spec=["args", "getCookie", "addCookie"])
 
         # Missing cookie
@@ -615,7 +632,14 @@ class OidcHandlerTestCase(HomeserverTestCase):
         self.handler._map_userinfo_to_user = simple_async_mock(return_value=user_id)
         self.handler._auth_handler.complete_sso_login = simple_async_mock()
         request = Mock(
-            spec=["args", "getCookie", "addCookie", "requestHeaders", "getClientIP"]
+            spec=[
+                "args",
+                "getCookie",
+                "addCookie",
+                "requestHeaders",
+                "getClientIP",
+                "get_user_agent",
+            ]
         )
 
         state = "state"
@@ -631,9 +655,8 @@ class OidcHandlerTestCase(HomeserverTestCase):
         request.args[b"code"] = [b"code"]
         request.args[b"state"] = [state.encode("utf-8")]
 
-        request.requestHeaders = Mock(spec=["getRawHeaders"])
-        request.requestHeaders.getRawHeaders.return_value = [b"Browser"]
         request.getClientIP.return_value = "10.0.0.1"
+        request.get_user_agent.return_value = "Browser"
 
         self.get_success(self.handler.handle_oidc_callback(request))
 
@@ -681,19 +704,23 @@ class OidcHandlerTestCase(HomeserverTestCase):
             ),
             MappingException,
         )
-        self.assertEqual(str(e.value), "mxid '@test_user_3:test' is already taken")
+        self.assertEqual(
+            str(e.value), "Mapping provider does not support de-duplicating Matrix IDs",
+        )
 
     @override_config({"oidc_config": {"allow_existing_users": True}})
     def test_map_userinfo_to_existing_user(self):
         """Existing users can log in with OpenID Connect when allow_existing_users is True."""
         store = self.hs.get_datastore()
-        user4 = UserID.from_string("@test_user_4:test")
+        user = UserID.from_string("@test_user:test")
         self.get_success(
-            store.register_user(user_id=user4.to_string(), password_hash=None)
+            store.register_user(user_id=user.to_string(), password_hash=None)
         )
+
+        # Map a user via SSO.
         userinfo = {
-            "sub": "test4",
-            "username": "test_user_4",
+            "sub": "test",
+            "username": "test_user",
         }
         token = {}
         mxid = self.get_success(
@@ -701,4 +728,137 @@ class OidcHandlerTestCase(HomeserverTestCase):
                 userinfo, token, "user-agent", "10.10.10.10"
             )
         )
-        self.assertEqual(mxid, "@test_user_4:test")
+        self.assertEqual(mxid, "@test_user:test")
+
+        # Subsequent calls should map to the same mxid.
+        mxid = self.get_success(
+            self.handler._map_userinfo_to_user(
+                userinfo, token, "user-agent", "10.10.10.10"
+            )
+        )
+        self.assertEqual(mxid, "@test_user:test")
+
+        # Note that a second SSO user can be mapped to the same Matrix ID. (This
+        # requires a unique sub, but something that maps to the same matrix ID,
+        # in this case we'll just use the same username. A more realistic example
+        # would be subs which are email addresses, and mapping from the localpart
+        # of the email, e.g. bob@foo.com and bob@bar.com -> @bob:test.)
+        userinfo = {
+            "sub": "test1",
+            "username": "test_user",
+        }
+        token = {}
+        mxid = self.get_success(
+            self.handler._map_userinfo_to_user(
+                userinfo, token, "user-agent", "10.10.10.10"
+            )
+        )
+        self.assertEqual(mxid, "@test_user:test")
+
+        # Register some non-exact matching cases.
+        user2 = UserID.from_string("@TEST_user_2:test")
+        self.get_success(
+            store.register_user(user_id=user2.to_string(), password_hash=None)
+        )
+        user2_caps = UserID.from_string("@test_USER_2:test")
+        self.get_success(
+            store.register_user(user_id=user2_caps.to_string(), password_hash=None)
+        )
+
+        # Attempting to login without matching a name exactly is an error.
+        userinfo = {
+            "sub": "test2",
+            "username": "TEST_USER_2",
+        }
+        e = self.get_failure(
+            self.handler._map_userinfo_to_user(
+                userinfo, token, "user-agent", "10.10.10.10"
+            ),
+            MappingException,
+        )
+        self.assertTrue(
+            str(e.value).startswith(
+                "Attempted to login as '@TEST_USER_2:test' but it matches more than one user inexactly:"
+            )
+        )
+
+        # Logging in when matching a name exactly should work.
+        user2 = UserID.from_string("@TEST_USER_2:test")
+        self.get_success(
+            store.register_user(user_id=user2.to_string(), password_hash=None)
+        )
+
+        mxid = self.get_success(
+            self.handler._map_userinfo_to_user(
+                userinfo, token, "user-agent", "10.10.10.10"
+            )
+        )
+        self.assertEqual(mxid, "@TEST_USER_2:test")
+
+    def test_map_userinfo_to_invalid_localpart(self):
+        """If the mapping provider generates an invalid localpart it should be rejected."""
+        userinfo = {
+            "sub": "test2",
+            "username": "föö",
+        }
+        token = {}
+
+        e = self.get_failure(
+            self.handler._map_userinfo_to_user(
+                userinfo, token, "user-agent", "10.10.10.10"
+            ),
+            MappingException,
+        )
+        self.assertEqual(str(e.value), "localpart is invalid: föö")
+
+    @override_config(
+        {
+            "oidc_config": {
+                "user_mapping_provider": {
+                    "module": __name__ + ".TestMappingProviderFailures"
+                }
+            }
+        }
+    )
+    def test_map_userinfo_to_user_retries(self):
+        """The mapping provider can retry generating an MXID if the MXID is already in use."""
+        store = self.hs.get_datastore()
+        self.get_success(
+            store.register_user(user_id="@test_user:test", password_hash=None)
+        )
+        userinfo = {
+            "sub": "test",
+            "username": "test_user",
+        }
+        token = {}
+        mxid = self.get_success(
+            self.handler._map_userinfo_to_user(
+                userinfo, token, "user-agent", "10.10.10.10"
+            )
+        )
+        # test_user is already taken, so test_user1 gets registered instead.
+        self.assertEqual(mxid, "@test_user1:test")
+
+        # Register all of the potential mxids for a particular OIDC username.
+        self.get_success(
+            store.register_user(user_id="@tester:test", password_hash=None)
+        )
+        for i in range(1, 3):
+            self.get_success(
+                store.register_user(user_id="@tester%d:test" % i, password_hash=None)
+            )
+
+        # Now attempt to map to a username, this will fail since all potential usernames are taken.
+        userinfo = {
+            "sub": "tester",
+            "username": "tester",
+        }
+        e = self.get_failure(
+            self.handler._map_userinfo_to_user(
+                userinfo, token, "user-agent", "10.10.10.10"
+            ),
+            MappingException,
+        )
+        self.assertEqual(
+            str(e.value), "Unable to generate a Matrix ID from the SSO response"
+        )
diff --git a/tests/handlers/test_password_providers.py b/tests/handlers/test_password_providers.py
new file mode 100644
index 0000000000..ceaf0902d2
--- /dev/null
+++ b/tests/handlers/test_password_providers.py
@@ -0,0 +1,580 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests for the password_auth_provider interface"""
+
+from typing import Any, Type, Union
+
+from mock import Mock
+
+from twisted.internet import defer
+
+import synapse
+from synapse.rest.client.v1 import login
+from synapse.rest.client.v2_alpha import devices
+from synapse.types import JsonDict
+
+from tests import unittest
+from tests.server import FakeChannel
+from tests.unittest import override_config
+
+# (possibly experimental) login flows we expect to appear in the list after the normal
+# ones
+ADDITIONAL_LOGIN_FLOWS = [{"type": "uk.half-shot.msc2778.login.application_service"}]
+
+# a mock instance which the dummy auth providers delegate to, so we can see what's going
+# on
+mock_password_provider = Mock()
+
+
+class PasswordOnlyAuthProvider:
+    """A password_provider which only implements `check_password`."""
+
+    @staticmethod
+    def parse_config(self):
+        pass
+
+    def __init__(self, config, account_handler):
+        pass
+
+    def check_password(self, *args):
+        return mock_password_provider.check_password(*args)
+
+
+class CustomAuthProvider:
+    """A password_provider which implements a custom login type."""
+
+    @staticmethod
+    def parse_config(self):
+        pass
+
+    def __init__(self, config, account_handler):
+        pass
+
+    def get_supported_login_types(self):
+        return {"test.login_type": ["test_field"]}
+
+    def check_auth(self, *args):
+        return mock_password_provider.check_auth(*args)
+
+
+class PasswordCustomAuthProvider:
+    """A password_provider which implements password login via `check_auth`, as well
+    as a custom type."""
+
+    @staticmethod
+    def parse_config(self):
+        pass
+
+    def __init__(self, config, account_handler):
+        pass
+
+    def get_supported_login_types(self):
+        return {"m.login.password": ["password"], "test.login_type": ["test_field"]}
+
+    def check_auth(self, *args):
+        return mock_password_provider.check_auth(*args)
+
+
+def providers_config(*providers: Type[Any]) -> dict:
+    """Returns a config dict that will enable the given password auth providers"""
+    return {
+        "password_providers": [
+            {"module": "%s.%s" % (__name__, provider.__qualname__), "config": {}}
+            for provider in providers
+        ]
+    }
+
+
+class PasswordAuthProviderTests(unittest.HomeserverTestCase):
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+        devices.register_servlets,
+    ]
+
+    def setUp(self):
+        # we use a global mock device, so make sure we are starting with a clean slate
+        mock_password_provider.reset_mock()
+        super().setUp()
+
+    @override_config(providers_config(PasswordOnlyAuthProvider))
+    def test_password_only_auth_provider_login(self):
+        # login flows should only have m.login.password
+        flows = self._get_login_flows()
+        self.assertEqual(flows, [{"type": "m.login.password"}] + ADDITIONAL_LOGIN_FLOWS)
+
+        # check_password must return an awaitable
+        mock_password_provider.check_password.return_value = defer.succeed(True)
+        channel = self._send_password_login("u", "p")
+        self.assertEqual(channel.code, 200, channel.result)
+        self.assertEqual("@u:test", channel.json_body["user_id"])
+        mock_password_provider.check_password.assert_called_once_with("@u:test", "p")
+        mock_password_provider.reset_mock()
+
+        # login with mxid should work too
+        channel = self._send_password_login("@u:bz", "p")
+        self.assertEqual(channel.code, 200, channel.result)
+        self.assertEqual("@u:bz", channel.json_body["user_id"])
+        mock_password_provider.check_password.assert_called_once_with("@u:bz", "p")
+        mock_password_provider.reset_mock()
+
+        # try a weird username / pass. Honestly it's unclear what we *expect* to happen
+        # in these cases, but at least we can guard against the API changing
+        # unexpectedly
+        channel = self._send_password_login(" USER🙂NAME ", " pASS\U0001F622word ")
+        self.assertEqual(channel.code, 200, channel.result)
+        self.assertEqual("@ USER🙂NAME :test", channel.json_body["user_id"])
+        mock_password_provider.check_password.assert_called_once_with(
+            "@ USER🙂NAME :test", " pASS😢word "
+        )
+
+    @override_config(providers_config(PasswordOnlyAuthProvider))
+    def test_password_only_auth_provider_ui_auth(self):
+        """UI Auth should delegate correctly to the password provider"""
+
+        # create the user, otherwise access doesn't work
+        module_api = self.hs.get_module_api()
+        self.get_success(module_api.register_user("u"))
+
+        # log in twice, to get two devices
+        mock_password_provider.check_password.return_value = defer.succeed(True)
+        tok1 = self.login("u", "p")
+        self.login("u", "p", device_id="dev2")
+        mock_password_provider.reset_mock()
+
+        # have the auth provider deny the request to start with
+        mock_password_provider.check_password.return_value = defer.succeed(False)
+
+        # make the initial request which returns a 401
+        session = self._start_delete_device_session(tok1, "dev2")
+        mock_password_provider.check_password.assert_not_called()
+
+        # Make another request providing the UI auth flow.
+        channel = self._authed_delete_device(tok1, "dev2", session, "u", "p")
+        self.assertEqual(channel.code, 401)  # XXX why not a 403?
+        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
+        mock_password_provider.check_password.assert_called_once_with("@u:test", "p")
+        mock_password_provider.reset_mock()
+
+        # Finally, check the request goes through when we allow it
+        mock_password_provider.check_password.return_value = defer.succeed(True)
+        channel = self._authed_delete_device(tok1, "dev2", session, "u", "p")
+        self.assertEqual(channel.code, 200)
+        mock_password_provider.check_password.assert_called_once_with("@u:test", "p")
+
+    @override_config(providers_config(PasswordOnlyAuthProvider))
+    def test_local_user_fallback_login(self):
+        """rejected login should fall back to local db"""
+        self.register_user("localuser", "localpass")
+
+        # check_password must return an awaitable
+        mock_password_provider.check_password.return_value = defer.succeed(False)
+        channel = self._send_password_login("u", "p")
+        self.assertEqual(channel.code, 403, channel.result)
+
+        channel = self._send_password_login("localuser", "localpass")
+        self.assertEqual(channel.code, 200, channel.result)
+        self.assertEqual("@localuser:test", channel.json_body["user_id"])
+
+    @override_config(providers_config(PasswordOnlyAuthProvider))
+    def test_local_user_fallback_ui_auth(self):
+        """rejected login should fall back to local db"""
+        self.register_user("localuser", "localpass")
+
+        # have the auth provider deny the request
+        mock_password_provider.check_password.return_value = defer.succeed(False)
+
+        # log in twice, to get two devices
+        tok1 = self.login("localuser", "localpass")
+        self.login("localuser", "localpass", device_id="dev2")
+        mock_password_provider.check_password.reset_mock()
+
+        # first delete should give a 401
+        session = self._start_delete_device_session(tok1, "dev2")
+        mock_password_provider.check_password.assert_not_called()
+
+        # Wrong password
+        channel = self._authed_delete_device(tok1, "dev2", session, "localuser", "xxx")
+        self.assertEqual(channel.code, 401)  # XXX why not a 403?
+        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
+        mock_password_provider.check_password.assert_called_once_with(
+            "@localuser:test", "xxx"
+        )
+        mock_password_provider.reset_mock()
+
+        # Right password
+        channel = self._authed_delete_device(
+            tok1, "dev2", session, "localuser", "localpass"
+        )
+        self.assertEqual(channel.code, 200)
+        mock_password_provider.check_password.assert_called_once_with(
+            "@localuser:test", "localpass"
+        )
+
+    @override_config(
+        {
+            **providers_config(PasswordOnlyAuthProvider),
+            "password_config": {"localdb_enabled": False},
+        }
+    )
+    def test_no_local_user_fallback_login(self):
+        """localdb_enabled can block login with the local password
+        """
+        self.register_user("localuser", "localpass")
+
+        # check_password must return an awaitable
+        mock_password_provider.check_password.return_value = defer.succeed(False)
+        channel = self._send_password_login("localuser", "localpass")
+        self.assertEqual(channel.code, 403)
+        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
+        mock_password_provider.check_password.assert_called_once_with(
+            "@localuser:test", "localpass"
+        )
+
+    @override_config(
+        {
+            **providers_config(PasswordOnlyAuthProvider),
+            "password_config": {"localdb_enabled": False},
+        }
+    )
+    def test_no_local_user_fallback_ui_auth(self):
+        """localdb_enabled can block ui auth with the local password
+        """
+        self.register_user("localuser", "localpass")
+
+        # allow login via the auth provider
+        mock_password_provider.check_password.return_value = defer.succeed(True)
+
+        # log in twice, to get two devices
+        tok1 = self.login("localuser", "p")
+        self.login("localuser", "p", device_id="dev2")
+        mock_password_provider.check_password.reset_mock()
+
+        # first delete should give a 401
+        channel = self._delete_device(tok1, "dev2")
+        self.assertEqual(channel.code, 401)
+        # m.login.password UIA is permitted because the auth provider allows it,
+        # even though the localdb does not.
+        self.assertEqual(channel.json_body["flows"], [{"stages": ["m.login.password"]}])
+        session = channel.json_body["session"]
+        mock_password_provider.check_password.assert_not_called()
+
+        # now try deleting with the local password
+        mock_password_provider.check_password.return_value = defer.succeed(False)
+        channel = self._authed_delete_device(
+            tok1, "dev2", session, "localuser", "localpass"
+        )
+        self.assertEqual(channel.code, 401)  # XXX why not a 403?
+        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
+        mock_password_provider.check_password.assert_called_once_with(
+            "@localuser:test", "localpass"
+        )
+
+    @override_config(
+        {
+            **providers_config(PasswordOnlyAuthProvider),
+            "password_config": {"enabled": False},
+        }
+    )
+    def test_password_auth_disabled(self):
+        """password auth doesn't work if it's disabled across the board"""
+        # login flows should be empty
+        flows = self._get_login_flows()
+        self.assertEqual(flows, ADDITIONAL_LOGIN_FLOWS)
+
+        # login shouldn't work and should be rejected with a 400 ("unknown login type")
+        channel = self._send_password_login("u", "p")
+        self.assertEqual(channel.code, 400, channel.result)
+        mock_password_provider.check_password.assert_not_called()
+
+    @override_config(providers_config(CustomAuthProvider))
+    def test_custom_auth_provider_login(self):
+        # login flows should have the custom flow and m.login.password, since we
+        # haven't disabled local password lookup.
+        # (password must come first, because reasons)
+        flows = self._get_login_flows()
+        self.assertEqual(
+            flows,
+            [{"type": "m.login.password"}, {"type": "test.login_type"}]
+            + ADDITIONAL_LOGIN_FLOWS,
+        )
+
+        # login with missing param should be rejected
+        channel = self._send_login("test.login_type", "u")
+        self.assertEqual(channel.code, 400, channel.result)
+        mock_password_provider.check_auth.assert_not_called()
+
+        mock_password_provider.check_auth.return_value = defer.succeed("@user:bz")
+        channel = self._send_login("test.login_type", "u", test_field="y")
+        self.assertEqual(channel.code, 200, channel.result)
+        self.assertEqual("@user:bz", channel.json_body["user_id"])
+        mock_password_provider.check_auth.assert_called_once_with(
+            "u", "test.login_type", {"test_field": "y"}
+        )
+        mock_password_provider.reset_mock()
+
+        # try a weird username. Again, it's unclear what we *expect* to happen
+        # in these cases, but at least we can guard against the API changing
+        # unexpectedly
+        mock_password_provider.check_auth.return_value = defer.succeed(
+            "@ MALFORMED! :bz"
+        )
+        channel = self._send_login("test.login_type", " USER🙂NAME ", test_field=" abc ")
+        self.assertEqual(channel.code, 200, channel.result)
+        self.assertEqual("@ MALFORMED! :bz", channel.json_body["user_id"])
+        mock_password_provider.check_auth.assert_called_once_with(
+            " USER🙂NAME ", "test.login_type", {"test_field": " abc "}
+        )
+
+    @override_config(providers_config(CustomAuthProvider))
+    def test_custom_auth_provider_ui_auth(self):
+        # register the user and log in twice, to get two devices
+        self.register_user("localuser", "localpass")
+        tok1 = self.login("localuser", "localpass")
+        self.login("localuser", "localpass", device_id="dev2")
+
+        # make the initial request which returns a 401
+        channel = self._delete_device(tok1, "dev2")
+        self.assertEqual(channel.code, 401)
+        # Ensure that flows are what is expected.
+        self.assertIn({"stages": ["m.login.password"]}, channel.json_body["flows"])
+        self.assertIn({"stages": ["test.login_type"]}, channel.json_body["flows"])
+        session = channel.json_body["session"]
+
+        # missing param
+        body = {
+            "auth": {
+                "type": "test.login_type",
+                "identifier": {"type": "m.id.user", "user": "localuser"},
+                "session": session,
+            },
+        }
+
+        channel = self._delete_device(tok1, "dev2", body)
+        self.assertEqual(channel.code, 400)
+        # there's a perfectly good M_MISSING_PARAM errcode, but heaven forfend we should
+        # use it...
+        self.assertIn("Missing parameters", channel.json_body["error"])
+        mock_password_provider.check_auth.assert_not_called()
+        mock_password_provider.reset_mock()
+
+        # right params, but authing as the wrong user
+        mock_password_provider.check_auth.return_value = defer.succeed("@user:bz")
+        body["auth"]["test_field"] = "foo"
+        channel = self._delete_device(tok1, "dev2", body)
+        self.assertEqual(channel.code, 403)
+        self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
+        mock_password_provider.check_auth.assert_called_once_with(
+            "localuser", "test.login_type", {"test_field": "foo"}
+        )
+        mock_password_provider.reset_mock()
+
+        # and finally, succeed
+        mock_password_provider.check_auth.return_value = defer.succeed(
+            "@localuser:test"
+        )
+        channel = self._delete_device(tok1, "dev2", body)
+        self.assertEqual(channel.code, 200)
+        mock_password_provider.check_auth.assert_called_once_with(
+            "localuser", "test.login_type", {"test_field": "foo"}
+        )
+
+    @override_config(providers_config(CustomAuthProvider))
+    def test_custom_auth_provider_callback(self):
+        callback = Mock(return_value=defer.succeed(None))
+
+        mock_password_provider.check_auth.return_value = defer.succeed(
+            ("@user:bz", callback)
+        )
+        channel = self._send_login("test.login_type", "u", test_field="y")
+        self.assertEqual(channel.code, 200, channel.result)
+        self.assertEqual("@user:bz", channel.json_body["user_id"])
+        mock_password_provider.check_auth.assert_called_once_with(
+            "u", "test.login_type", {"test_field": "y"}
+        )
+
+        # check the args to the callback
+        callback.assert_called_once()
+        call_args, call_kwargs = callback.call_args
+        # should be one positional arg
+        self.assertEqual(len(call_args), 1)
+        self.assertEqual(call_args[0]["user_id"], "@user:bz")
+        for p in ["user_id", "access_token", "device_id", "home_server"]:
+            self.assertIn(p, call_args[0])
+
+    @override_config(
+        {**providers_config(CustomAuthProvider), "password_config": {"enabled": False}}
+    )
+    def test_custom_auth_password_disabled(self):
+        """Test login with a custom auth provider where password login is disabled"""
+        self.register_user("localuser", "localpass")
+
+        flows = self._get_login_flows()
+        self.assertEqual(flows, [{"type": "test.login_type"}] + ADDITIONAL_LOGIN_FLOWS)
+
+        # login shouldn't work and should be rejected with a 400 ("unknown login type")
+        channel = self._send_password_login("localuser", "localpass")
+        self.assertEqual(channel.code, 400, channel.result)
+        mock_password_provider.check_auth.assert_not_called()
+
+    @override_config(
+        {
+            **providers_config(PasswordCustomAuthProvider),
+            "password_config": {"enabled": False},
+        }
+    )
+    def test_password_custom_auth_password_disabled_login(self):
+        """log in with a custom auth provider which implements password, but password
+        login is disabled"""
+        self.register_user("localuser", "localpass")
+
+        flows = self._get_login_flows()
+        self.assertEqual(flows, [{"type": "test.login_type"}] + ADDITIONAL_LOGIN_FLOWS)
+
+        # login shouldn't work and should be rejected with a 400 ("unknown login type")
+        channel = self._send_password_login("localuser", "localpass")
+        self.assertEqual(channel.code, 400, channel.result)
+        mock_password_provider.check_auth.assert_not_called()
+
+    @override_config(
+        {
+            **providers_config(PasswordCustomAuthProvider),
+            "password_config": {"enabled": False},
+        }
+    )
+    def test_password_custom_auth_password_disabled_ui_auth(self):
+        """UI Auth with a custom auth provider which implements password, but password
+        login is disabled"""
+        # register the user and log in twice via the test login type to get two devices,
+        self.register_user("localuser", "localpass")
+        mock_password_provider.check_auth.return_value = defer.succeed(
+            "@localuser:test"
+        )
+        channel = self._send_login("test.login_type", "localuser", test_field="")
+        self.assertEqual(channel.code, 200, channel.result)
+        tok1 = channel.json_body["access_token"]
+
+        channel = self._send_login(
+            "test.login_type", "localuser", test_field="", device_id="dev2"
+        )
+        self.assertEqual(channel.code, 200, channel.result)
+
+        # make the initial request which returns a 401
+        channel = self._delete_device(tok1, "dev2")
+        self.assertEqual(channel.code, 401)
+        # Ensure that flows are what is expected. In particular, "password" should *not*
+        # be present.
+        self.assertIn({"stages": ["test.login_type"]}, channel.json_body["flows"])
+        session = channel.json_body["session"]
+
+        mock_password_provider.reset_mock()
+
+        # check that auth with password is rejected
+        body = {
+            "auth": {
+                "type": "m.login.password",
+                "identifier": {"type": "m.id.user", "user": "localuser"},
+                "password": "localpass",
+                "session": session,
+            },
+        }
+
+        channel = self._delete_device(tok1, "dev2", body)
+        self.assertEqual(channel.code, 400)
+        self.assertEqual(
+            "Password login has been disabled.", channel.json_body["error"]
+        )
+        mock_password_provider.check_auth.assert_not_called()
+        mock_password_provider.reset_mock()
+
+        # successful auth
+        body["auth"]["type"] = "test.login_type"
+        body["auth"]["test_field"] = "x"
+        channel = self._delete_device(tok1, "dev2", body)
+        self.assertEqual(channel.code, 200)
+        mock_password_provider.check_auth.assert_called_once_with(
+            "localuser", "test.login_type", {"test_field": "x"}
+        )
+
+    @override_config(
+        {
+            **providers_config(CustomAuthProvider),
+            "password_config": {"localdb_enabled": False},
+        }
+    )
+    def test_custom_auth_no_local_user_fallback(self):
+        """Test login with a custom auth provider where the local db is disabled"""
+        self.register_user("localuser", "localpass")
+
+        flows = self._get_login_flows()
+        self.assertEqual(flows, [{"type": "test.login_type"}] + ADDITIONAL_LOGIN_FLOWS)
+
+        # password login shouldn't work and should be rejected with a 400
+        # ("unknown login type")
+        channel = self._send_password_login("localuser", "localpass")
+        self.assertEqual(channel.code, 400, channel.result)
+
+    def _get_login_flows(self) -> JsonDict:
+        _, channel = self.make_request("GET", "/_matrix/client/r0/login")
+        self.assertEqual(channel.code, 200, channel.result)
+        return channel.json_body["flows"]
+
+    def _send_password_login(self, user: str, password: str) -> FakeChannel:
+        return self._send_login(type="m.login.password", user=user, password=password)
+
+    def _send_login(self, type, user, **params) -> FakeChannel:
+        params.update({"identifier": {"type": "m.id.user", "user": user}, "type": type})
+        _, channel = self.make_request("POST", "/_matrix/client/r0/login", params)
+        return channel
+
+    def _start_delete_device_session(self, access_token, device_id) -> str:
+        """Make an initial delete device request, and return the UI Auth session ID"""
+        channel = self._delete_device(access_token, device_id)
+        self.assertEqual(channel.code, 401)
+        # Ensure that flows are what is expected.
+        self.assertIn({"stages": ["m.login.password"]}, channel.json_body["flows"])
+        return channel.json_body["session"]
+
+    def _authed_delete_device(
+        self,
+        access_token: str,
+        device_id: str,
+        session: str,
+        user_id: str,
+        password: str,
+    ) -> FakeChannel:
+        """Make a delete device request, authenticating with the given uid/password"""
+        return self._delete_device(
+            access_token,
+            device_id,
+            {
+                "auth": {
+                    "type": "m.login.password",
+                    "identifier": {"type": "m.id.user", "user": user_id},
+                    "password": password,
+                    "session": session,
+                },
+            },
+        )
+
+    def _delete_device(
+        self, access_token: str, device: str, body: Union[JsonDict, bytes] = b"",
+    ) -> FakeChannel:
+        """Delete an individual device."""
+        _, channel = self.make_request(
+            "DELETE", "devices/" + device, body, access_token=access_token
+        )
+        return channel
diff --git a/tests/handlers/test_presence.py b/tests/handlers/test_presence.py
index 306dcfe944..8ed67640f8 100644
--- a/tests/handlers/test_presence.py
+++ b/tests/handlers/test_presence.py
@@ -470,7 +470,7 @@ class PresenceJoinTestCase(unittest.HomeserverTestCase):
     def prepare(self, reactor, clock, hs):
         self.federation_sender = hs.get_federation_sender()
         self.event_builder_factory = hs.get_event_builder_factory()
-        self.federation_handler = hs.get_handlers().federation_handler
+        self.federation_handler = hs.get_federation_handler()
         self.presence_handler = hs.get_presence_handler()
 
         # self.event_builder_for_2 = EventBuilderFactory(hs)
@@ -615,7 +615,7 @@ class PresenceJoinTestCase(unittest.HomeserverTestCase):
             self.store.get_latest_event_ids_in_room(room_id)
         )
 
-        event = self.get_success(builder.build(prev_event_ids))
+        event = self.get_success(builder.build(prev_event_ids, None))
 
         self.get_success(self.federation_handler.on_receive_pdu(hostname, event))
 
diff --git a/tests/handlers/test_profile.py b/tests/handlers/test_profile.py
index 1cef10feff..1999bcbb38 100644
--- a/tests/handlers/test_profile.py
+++ b/tests/handlers/test_profile.py
@@ -20,7 +20,6 @@ from twisted.internet import defer
 
 import synapse.types
 from synapse.api.errors import AuthError, SynapseError
-from synapse.handlers.profile import MasterProfileHandler
 from synapse.types import UserID
 
 from tests import unittest
@@ -28,11 +27,6 @@ from tests.test_utils import make_awaitable
 from tests.utils import setup_test_homeserver
 
 
-class ProfileHandlers:
-    def __init__(self, hs):
-        self.profile_handler = MasterProfileHandler(hs)
-
-
 class ProfileTestCase(unittest.TestCase):
     """ Tests profile management. """
 
@@ -51,7 +45,6 @@ class ProfileTestCase(unittest.TestCase):
         hs = yield setup_test_homeserver(
             self.addCleanup,
             http_client=None,
-            handlers=None,
             resource_for_federation=Mock(),
             federation_client=self.mock_federation,
             federation_server=Mock(),
diff --git a/tests/handlers/test_register.py b/tests/handlers/test_register.py
index 312c03c83d..d979aadcd6 100644
--- a/tests/handlers/test_register.py
+++ b/tests/handlers/test_register.py
@@ -18,7 +18,6 @@ from mock import Mock
 from synapse.api.auth import Auth
 from synapse.api.constants import UserTypes
 from synapse.api.errors import Codes, ResourceLimitError, SynapseError
-from synapse.handlers.register import RegistrationHandler
 from synapse.http.site import SynapseRequest
 from synapse.rest.client.v2_alpha.register import (
     _map_email_to_displayname,
@@ -35,11 +34,6 @@ from tests.utils import mock_getRawHeaders
 from .. import unittest
 
 
-class RegistrationHandlers:
-    def __init__(self, hs):
-        self.registration_handler = RegistrationHandler(hs)
-
-
 class RegistrationTestCase(unittest.HomeserverTestCase):
     """ Tests the RegistrationHandler. """
 
@@ -164,7 +158,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
         room_alias_str = "#room:test"
         user_id = self.get_success(self.handler.register_user(localpart="jeff"))
         rooms = self.get_success(self.store.get_rooms_for_user(user_id))
-        directory_handler = self.hs.get_handlers().directory_handler
+        directory_handler = self.hs.get_directory_handler()
         room_alias = RoomAlias.from_string(room_alias_str)
         room_id = self.get_success(directory_handler.get_association(room_alias))
 
@@ -203,7 +197,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
         user_id = self.get_success(self.handler.register_user(localpart="support"))
         rooms = self.get_success(self.store.get_rooms_for_user(user_id))
         self.assertEqual(len(rooms), 0)
-        directory_handler = self.hs.get_handlers().directory_handler
+        directory_handler = self.hs.get_directory_handler()
         room_alias = RoomAlias.from_string(room_alias_str)
         self.get_failure(directory_handler.get_association(room_alias), SynapseError)
 
@@ -215,7 +209,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
         self.store.is_real_user = Mock(return_value=make_awaitable(True))
         user_id = self.get_success(self.handler.register_user(localpart="real"))
         rooms = self.get_success(self.store.get_rooms_for_user(user_id))
-        directory_handler = self.hs.get_handlers().directory_handler
+        directory_handler = self.hs.get_directory_handler()
         room_alias = RoomAlias.from_string(room_alias_str)
         room_id = self.get_success(directory_handler.get_association(room_alias))
 
@@ -247,7 +241,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
         user_id = self.get_success(self.handler.register_user(localpart="jeff"))
 
         # Ensure the room was created.
-        directory_handler = self.hs.get_handlers().directory_handler
+        directory_handler = self.hs.get_directory_handler()
         room_alias = RoomAlias.from_string(room_alias_str)
         room_id = self.get_success(directory_handler.get_association(room_alias))
 
@@ -276,7 +270,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
         user_id = self.get_success(self.handler.register_user(localpart="jeff"))
 
         # Ensure the room was created.
-        directory_handler = self.hs.get_handlers().directory_handler
+        directory_handler = self.hs.get_directory_handler()
         room_alias = RoomAlias.from_string(room_alias_str)
         room_id = self.get_success(directory_handler.get_association(room_alias))
 
@@ -314,7 +308,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
         user_id = self.get_success(self.handler.register_user(localpart="jeff"))
 
         # Ensure the room was created.
-        directory_handler = self.hs.get_handlers().directory_handler
+        directory_handler = self.hs.get_directory_handler()
         room_alias = RoomAlias.from_string(room_alias_str)
         room_id = self.get_success(directory_handler.get_association(room_alias))
 
@@ -357,7 +351,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
         )
 
         # Ensure the room was created.
-        directory_handler = self.hs.get_handlers().directory_handler
+        directory_handler = self.hs.get_directory_handler()
         room_alias = RoomAlias.from_string(room_alias_str)
         room_id = self.get_success(directory_handler.get_association(room_alias))
 
@@ -394,7 +388,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
         user_id = self.get_success(self.handler.register_user(localpart="jeff"))
 
         # Ensure the room was created.
-        directory_handler = self.hs.get_handlers().directory_handler
+        directory_handler = self.hs.get_directory_handler()
         room_alias = RoomAlias.from_string(room_alias_str)
         room_id = self.get_success(directory_handler.get_association(room_alias))
 
@@ -423,7 +417,7 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            event_creation_handler.send_nonmember_event(requester, event, context)
+            event_creation_handler.handle_new_client_event(requester, event, context)
         )
 
         # Register a second user, which won't be be in the room (or even have an invite)
@@ -626,7 +620,6 @@ class RegistrationTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", "register", body
         )  # type: SynapseRequest, FakeChannel
-        self.render(request)
 
         self.assertEqual(request.code, expected_response)
         return channel
diff --git a/tests/handlers/test_saml.py b/tests/handlers/test_saml.py
new file mode 100644
index 0000000000..45dc17aba5
--- /dev/null
+++ b/tests/handlers/test_saml.py
@@ -0,0 +1,196 @@
+#  Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+import attr
+
+from synapse.api.errors import RedirectException
+from synapse.handlers.sso import MappingException
+
+from tests.unittest import HomeserverTestCase, override_config
+
+# These are a few constants that are used as config parameters in the tests.
+BASE_URL = "https://synapse/"
+
+
+@attr.s
+class FakeAuthnResponse:
+    ava = attr.ib(type=dict)
+
+
+class TestMappingProvider:
+    def __init__(self, config, module):
+        pass
+
+    @staticmethod
+    def parse_config(config):
+        return
+
+    @staticmethod
+    def get_saml_attributes(config):
+        return {"uid"}, {"displayName"}
+
+    def get_remote_user_id(self, saml_response, client_redirect_url):
+        return saml_response.ava["uid"]
+
+    def saml_response_to_user_attributes(
+        self, saml_response, failures, client_redirect_url
+    ):
+        localpart = saml_response.ava["username"] + (str(failures) if failures else "")
+        return {"mxid_localpart": localpart, "displayname": None}
+
+
+class TestRedirectMappingProvider(TestMappingProvider):
+    def saml_response_to_user_attributes(
+        self, saml_response, failures, client_redirect_url
+    ):
+        raise RedirectException(b"https://custom-saml-redirect/")
+
+
+class SamlHandlerTestCase(HomeserverTestCase):
+    def default_config(self):
+        config = super().default_config()
+        config["public_baseurl"] = BASE_URL
+        saml_config = {
+            "sp_config": {"metadata": {}},
+            # Disable grandfathering.
+            "grandfathered_mxid_source_attribute": None,
+            "user_mapping_provider": {"module": __name__ + ".TestMappingProvider"},
+        }
+
+        # Update this config with what's in the default config so that
+        # override_config works as expected.
+        saml_config.update(config.get("saml2_config", {}))
+        config["saml2_config"] = saml_config
+
+        return config
+
+    def make_homeserver(self, reactor, clock):
+        hs = self.setup_test_homeserver()
+
+        self.handler = hs.get_saml_handler()
+
+        # Reduce the number of attempts when generating MXIDs.
+        sso_handler = hs.get_sso_handler()
+        sso_handler._MAP_USERNAME_RETRIES = 3
+
+        return hs
+
+    def test_map_saml_response_to_user(self):
+        """Ensure that mapping the SAML response returned from a provider to an MXID works properly."""
+        saml_response = FakeAuthnResponse({"uid": "test_user", "username": "test_user"})
+        # The redirect_url doesn't matter with the default user mapping provider.
+        redirect_url = ""
+        mxid = self.get_success(
+            self.handler._map_saml_response_to_user(
+                saml_response, redirect_url, "user-agent", "10.10.10.10"
+            )
+        )
+        self.assertEqual(mxid, "@test_user:test")
+
+    @override_config({"saml2_config": {"grandfathered_mxid_source_attribute": "mxid"}})
+    def test_map_saml_response_to_existing_user(self):
+        """Existing users can log in with SAML account."""
+        store = self.hs.get_datastore()
+        self.get_success(
+            store.register_user(user_id="@test_user:test", password_hash=None)
+        )
+
+        # Map a user via SSO.
+        saml_response = FakeAuthnResponse(
+            {"uid": "tester", "mxid": ["test_user"], "username": "test_user"}
+        )
+        redirect_url = ""
+        mxid = self.get_success(
+            self.handler._map_saml_response_to_user(
+                saml_response, redirect_url, "user-agent", "10.10.10.10"
+            )
+        )
+        self.assertEqual(mxid, "@test_user:test")
+
+        # Subsequent calls should map to the same mxid.
+        mxid = self.get_success(
+            self.handler._map_saml_response_to_user(
+                saml_response, redirect_url, "user-agent", "10.10.10.10"
+            )
+        )
+        self.assertEqual(mxid, "@test_user:test")
+
+    def test_map_saml_response_to_invalid_localpart(self):
+        """If the mapping provider generates an invalid localpart it should be rejected."""
+        saml_response = FakeAuthnResponse({"uid": "test", "username": "föö"})
+        redirect_url = ""
+        e = self.get_failure(
+            self.handler._map_saml_response_to_user(
+                saml_response, redirect_url, "user-agent", "10.10.10.10"
+            ),
+            MappingException,
+        )
+        self.assertEqual(str(e.value), "localpart is invalid: föö")
+
+    def test_map_saml_response_to_user_retries(self):
+        """The mapping provider can retry generating an MXID if the MXID is already in use."""
+        store = self.hs.get_datastore()
+        self.get_success(
+            store.register_user(user_id="@test_user:test", password_hash=None)
+        )
+        saml_response = FakeAuthnResponse({"uid": "test", "username": "test_user"})
+        redirect_url = ""
+        mxid = self.get_success(
+            self.handler._map_saml_response_to_user(
+                saml_response, redirect_url, "user-agent", "10.10.10.10"
+            )
+        )
+        # test_user is already taken, so test_user1 gets registered instead.
+        self.assertEqual(mxid, "@test_user1:test")
+
+        # Register all of the potential mxids for a particular SAML username.
+        self.get_success(
+            store.register_user(user_id="@tester:test", password_hash=None)
+        )
+        for i in range(1, 3):
+            self.get_success(
+                store.register_user(user_id="@tester%d:test" % i, password_hash=None)
+            )
+
+        # Now attempt to map to a username, this will fail since all potential usernames are taken.
+        saml_response = FakeAuthnResponse({"uid": "tester", "username": "tester"})
+        e = self.get_failure(
+            self.handler._map_saml_response_to_user(
+                saml_response, redirect_url, "user-agent", "10.10.10.10"
+            ),
+            MappingException,
+        )
+        self.assertEqual(
+            str(e.value), "Unable to generate a Matrix ID from the SSO response"
+        )
+
+    @override_config(
+        {
+            "saml2_config": {
+                "user_mapping_provider": {
+                    "module": __name__ + ".TestRedirectMappingProvider"
+                },
+            }
+        }
+    )
+    def test_map_saml_response_redirect(self):
+        saml_response = FakeAuthnResponse({"uid": "test", "username": "test_user"})
+        redirect_url = ""
+        e = self.get_failure(
+            self.handler._map_saml_response_to_user(
+                saml_response, redirect_url, "user-agent", "10.10.10.10"
+            ),
+            RedirectException,
+        )
+        self.assertEqual(e.value.location, b"https://custom-saml-redirect/")
diff --git a/tests/handlers/test_sync.py b/tests/handlers/test_sync.py
index e178d7765b..e62586142e 100644
--- a/tests/handlers/test_sync.py
+++ b/tests/handlers/test_sync.py
@@ -16,7 +16,7 @@
 from synapse.api.errors import Codes, ResourceLimitError
 from synapse.api.filtering import DEFAULT_FILTER_COLLECTION
 from synapse.handlers.sync import SyncConfig
-from synapse.types import UserID
+from synapse.types import UserID, create_requester
 
 import tests.unittest
 import tests.utils
@@ -38,6 +38,7 @@ class SyncTestCase(tests.unittest.HomeserverTestCase):
         user_id1 = "@user1:test"
         user_id2 = "@user2:test"
         sync_config = self._generate_sync_config(user_id1)
+        requester = create_requester(user_id1)
 
         self.reactor.advance(100)  # So we get not 0 time
         self.auth_blocking._limit_usage_by_mau = True
@@ -45,21 +46,26 @@ class SyncTestCase(tests.unittest.HomeserverTestCase):
 
         # Check that the happy case does not throw errors
         self.get_success(self.store.upsert_monthly_active_user(user_id1))
-        self.get_success(self.sync_handler.wait_for_sync_for_user(sync_config))
+        self.get_success(
+            self.sync_handler.wait_for_sync_for_user(requester, sync_config)
+        )
 
         # Test that global lock works
         self.auth_blocking._hs_disabled = True
         e = self.get_failure(
-            self.sync_handler.wait_for_sync_for_user(sync_config), ResourceLimitError
+            self.sync_handler.wait_for_sync_for_user(requester, sync_config),
+            ResourceLimitError,
         )
         self.assertEquals(e.value.errcode, Codes.RESOURCE_LIMIT_EXCEEDED)
 
         self.auth_blocking._hs_disabled = False
 
         sync_config = self._generate_sync_config(user_id2)
+        requester = create_requester(user_id2)
 
         e = self.get_failure(
-            self.sync_handler.wait_for_sync_for_user(sync_config), ResourceLimitError
+            self.sync_handler.wait_for_sync_for_user(requester, sync_config),
+            ResourceLimitError,
         )
         self.assertEquals(e.value.errcode, Codes.RESOURCE_LIMIT_EXCEEDED)
 
diff --git a/tests/handlers/test_typing.py b/tests/handlers/test_typing.py
index 3fec09ea8a..abbdf2d524 100644
--- a/tests/handlers/test_typing.py
+++ b/tests/handlers/test_typing.py
@@ -65,26 +65,6 @@ class TypingNotificationsTestCase(unittest.HomeserverTestCase):
         mock_federation_client = Mock(spec=["put_json"])
         mock_federation_client.put_json.return_value = defer.succeed((200, "OK"))
 
-        datastores = Mock()
-        datastores.main = Mock(
-            spec=[
-                # Bits that Federation needs
-                "prep_send_transaction",
-                "delivered_txn",
-                "get_received_txn_response",
-                "set_received_txn_response",
-                "get_destination_last_successful_stream_ordering",
-                "get_destination_retry_timings",
-                "get_devices_by_remote",
-                "maybe_store_room_on_invite",
-                # Bits that user_directory needs
-                "get_user_directory_stream_pos",
-                "get_current_state_deltas",
-                "get_device_updates_by_remote",
-                "get_room_max_stream_ordering",
-            ]
-        )
-
         # the tests assume that we are starting at unix time 1000
         reactor.pump((1000,))
 
@@ -95,8 +75,6 @@ class TypingNotificationsTestCase(unittest.HomeserverTestCase):
             replication_streams={},
         )
 
-        hs.datastores = datastores
-
         return hs
 
     def prepare(self, reactor, clock, hs):
@@ -114,16 +92,16 @@ class TypingNotificationsTestCase(unittest.HomeserverTestCase):
             "retry_interval": 0,
             "failure_ts": None,
         }
-        self.datastore.get_destination_retry_timings.return_value = defer.succeed(
-            retry_timings_res
+        self.datastore.get_destination_retry_timings = Mock(
+            return_value=defer.succeed(retry_timings_res)
         )
 
-        self.datastore.get_device_updates_by_remote.return_value = make_awaitable(
-            (0, [])
+        self.datastore.get_device_updates_by_remote = Mock(
+            return_value=make_awaitable((0, []))
         )
 
-        self.datastore.get_destination_last_successful_stream_ordering.return_value = make_awaitable(
-            None
+        self.datastore.get_destination_last_successful_stream_ordering = Mock(
+            return_value=make_awaitable(None)
         )
 
         def get_received_txn_response(*args):
@@ -145,17 +123,19 @@ class TypingNotificationsTestCase(unittest.HomeserverTestCase):
 
         self.datastore.get_joined_hosts_for_room = get_joined_hosts_for_room
 
-        def get_users_in_room(room_id):
-            return defer.succeed({str(u) for u in self.room_members})
+        async def get_users_in_room(room_id):
+            return {str(u) for u in self.room_members}
 
         self.datastore.get_users_in_room = get_users_in_room
 
-        self.datastore.get_user_directory_stream_pos.side_effect = (
-            # we deliberately return a non-None stream pos to avoid doing an initial_spam
-            lambda: make_awaitable(1)
+        self.datastore.get_user_directory_stream_pos = Mock(
+            side_effect=(
+                # we deliberately return a non-None stream pos to avoid doing an initial_spam
+                lambda: make_awaitable(1)
+            )
         )
 
-        self.datastore.get_current_state_deltas.return_value = (0, None)
+        self.datastore.get_current_state_deltas = Mock(return_value=(0, None))
 
         self.datastore.get_to_device_stream_token = lambda: 0
         self.datastore.get_new_device_msgs_for_remote = lambda *args, **kargs: make_awaitable(
@@ -248,7 +228,6 @@ class TypingNotificationsTestCase(unittest.HomeserverTestCase):
             ),
             federation_auth_origin=b"farm",
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         self.on_new_event.assert_has_calls([call("typing_key", 1, rooms=[ROOM_ID])])
diff --git a/tests/handlers/test_user_directory.py b/tests/handlers/test_user_directory.py
index 48f750d357..4f6a912ac4 100644
--- a/tests/handlers/test_user_directory.py
+++ b/tests/handlers/test_user_directory.py
@@ -537,7 +537,6 @@ class TestUserDirSearchDisabled(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", b"user_directory/search", b'{"search_term":"user2"}'
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
         self.assertTrue(len(channel.json_body["results"]) > 0)
 
@@ -546,7 +545,6 @@ class TestUserDirSearchDisabled(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", b"user_directory/search", b'{"search_term":"user2"}'
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
         self.assertTrue(len(channel.json_body["results"]) == 0)
 
@@ -587,7 +585,6 @@ class UserInfoTestCase(unittest.FederatingHomeserverTestCase):
             access_token=user_three_token,
             shorthand=False,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
         # Check the state of user_one matches
@@ -617,7 +614,6 @@ class UserInfoTestCase(unittest.FederatingHomeserverTestCase):
             path="/_matrix/federation/unstable/users/info",
             content={"user_ids": [user_one, user_two, user_three]},
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         # Check the state of user_one matches
@@ -660,7 +656,7 @@ class UserInfoTestCase(unittest.FederatingHomeserverTestCase):
         return user_one, user_two, user_three, user_three_token
 
     def expire(self, user_id_to_expire, admin_tok):
-        url = "/_matrix/client/unstable/admin/account_validity/validity"
+        url = "/_synapse/admin/v1/account_validity/validity"
         request_data = {
             "user_id": user_id_to_expire,
             "expiration_ts": 0,
@@ -669,7 +665,6 @@ class UserInfoTestCase(unittest.FederatingHomeserverTestCase):
         request, channel = self.make_request(
             "POST", url, request_data, access_token=admin_tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
     def deactivate(self, user_id, tok):
@@ -680,5 +675,4 @@ class UserInfoTestCase(unittest.FederatingHomeserverTestCase):
         request, channel = self.make_request(
             "POST", "account/deactivate", request_data, access_token=tok
         )
-        self.render(request)
         self.assertEqual(request.code, 200)
diff --git a/tests/http/test_additional_resource.py b/tests/http/test_additional_resource.py
index 62d36c2906..05e9c449be 100644
--- a/tests/http/test_additional_resource.py
+++ b/tests/http/test_additional_resource.py
@@ -17,6 +17,7 @@
 from synapse.http.additional_resource import AdditionalResource
 from synapse.http.server import respond_with_json
 
+from tests.server import FakeSite, make_request
 from tests.unittest import HomeserverTestCase
 
 
@@ -43,20 +44,18 @@ class AdditionalResourceTests(HomeserverTestCase):
 
     def test_async(self):
         handler = _AsyncTestCustomEndpoint({}, None).handle_request
-        self.resource = AdditionalResource(self.hs, handler)
+        resource = AdditionalResource(self.hs, handler)
 
-        request, channel = self.make_request("GET", "/")
-        self.render(request)
+        request, channel = make_request(self.reactor, FakeSite(resource), "GET", "/")
 
         self.assertEqual(request.code, 200)
         self.assertEqual(channel.json_body, {"some_key": "some_value_async"})
 
     def test_sync(self):
         handler = _SyncTestCustomEndpoint({}, None).handle_request
-        self.resource = AdditionalResource(self.hs, handler)
+        resource = AdditionalResource(self.hs, handler)
 
-        request, channel = self.make_request("GET", "/")
-        self.render(request)
+        request, channel = make_request(self.reactor, FakeSite(resource), "GET", "/")
 
         self.assertEqual(request.code, 200)
         self.assertEqual(channel.json_body, {"some_key": "some_value_sync"})
diff --git a/tests/logging/__init__.py b/tests/logging/__init__.py
index e69de29bb2..a58d51441c 100644
--- a/tests/logging/__init__.py
+++ b/tests/logging/__init__.py
@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+
+
+class LoggerCleanupMixin:
+    def get_logger(self, handler):
+        """
+        Attach a handler to a logger and add clean-ups to remove revert this.
+        """
+        # Create a logger and add the handler to it.
+        logger = logging.getLogger(__name__)
+        logger.addHandler(handler)
+
+        # Ensure the logger actually logs something.
+        logger.setLevel(logging.INFO)
+
+        # Ensure the logger gets cleaned-up appropriately.
+        self.addCleanup(logger.removeHandler, handler)
+        self.addCleanup(logger.setLevel, logging.NOTSET)
+
+        return logger
diff --git a/tests/logging/test_remote_handler.py b/tests/logging/test_remote_handler.py
new file mode 100644
index 0000000000..4bc27a1d7d
--- /dev/null
+++ b/tests/logging/test_remote_handler.py
@@ -0,0 +1,169 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from twisted.test.proto_helpers import AccumulatingProtocol
+
+from synapse.logging import RemoteHandler
+
+from tests.logging import LoggerCleanupMixin
+from tests.server import FakeTransport, get_clock
+from tests.unittest import TestCase
+
+
+def connect_logging_client(reactor, client_id):
+    # This is essentially tests.server.connect_client, but disabling autoflush on
+    # the client transport. This is necessary to avoid an infinite loop due to
+    # sending of data via the logging transport causing additional logs to be
+    # written.
+    factory = reactor.tcpClients.pop(client_id)[2]
+    client = factory.buildProtocol(None)
+    server = AccumulatingProtocol()
+    server.makeConnection(FakeTransport(client, reactor))
+    client.makeConnection(FakeTransport(server, reactor, autoflush=False))
+
+    return client, server
+
+
+class RemoteHandlerTestCase(LoggerCleanupMixin, TestCase):
+    def setUp(self):
+        self.reactor, _ = get_clock()
+
+    def test_log_output(self):
+        """
+        The remote handler delivers logs over TCP.
+        """
+        handler = RemoteHandler("127.0.0.1", 9000, _reactor=self.reactor)
+        logger = self.get_logger(handler)
+
+        logger.info("Hello there, %s!", "wally")
+
+        # Trigger the connection
+        client, server = connect_logging_client(self.reactor, 0)
+
+        # Trigger data being sent
+        client.transport.flush()
+
+        # One log message, with a single trailing newline
+        logs = server.data.decode("utf8").splitlines()
+        self.assertEqual(len(logs), 1)
+        self.assertEqual(server.data.count(b"\n"), 1)
+
+        # Ensure the data passed through properly.
+        self.assertEqual(logs[0], "Hello there, wally!")
+
+    def test_log_backpressure_debug(self):
+        """
+        When backpressure is hit, DEBUG logs will be shed.
+        """
+        handler = RemoteHandler(
+            "127.0.0.1", 9000, maximum_buffer=10, _reactor=self.reactor
+        )
+        logger = self.get_logger(handler)
+
+        # Send some debug messages
+        for i in range(0, 3):
+            logger.debug("debug %s" % (i,))
+
+        # Send a bunch of useful messages
+        for i in range(0, 7):
+            logger.info("info %s" % (i,))
+
+        # The last debug message pushes it past the maximum buffer
+        logger.debug("too much debug")
+
+        # Allow the reconnection
+        client, server = connect_logging_client(self.reactor, 0)
+        client.transport.flush()
+
+        # Only the 7 infos made it through, the debugs were elided
+        logs = server.data.splitlines()
+        self.assertEqual(len(logs), 7)
+        self.assertNotIn(b"debug", server.data)
+
+    def test_log_backpressure_info(self):
+        """
+        When backpressure is hit, DEBUG and INFO logs will be shed.
+        """
+        handler = RemoteHandler(
+            "127.0.0.1", 9000, maximum_buffer=10, _reactor=self.reactor
+        )
+        logger = self.get_logger(handler)
+
+        # Send some debug messages
+        for i in range(0, 3):
+            logger.debug("debug %s" % (i,))
+
+        # Send a bunch of useful messages
+        for i in range(0, 10):
+            logger.warning("warn %s" % (i,))
+
+        # Send a bunch of info messages
+        for i in range(0, 3):
+            logger.info("info %s" % (i,))
+
+        # The last debug message pushes it past the maximum buffer
+        logger.debug("too much debug")
+
+        # Allow the reconnection
+        client, server = connect_logging_client(self.reactor, 0)
+        client.transport.flush()
+
+        # The 10 warnings made it through, the debugs and infos were elided
+        logs = server.data.splitlines()
+        self.assertEqual(len(logs), 10)
+        self.assertNotIn(b"debug", server.data)
+        self.assertNotIn(b"info", server.data)
+
+    def test_log_backpressure_cut_middle(self):
+        """
+        When backpressure is hit, and no more DEBUG and INFOs cannot be culled,
+        it will cut the middle messages out.
+        """
+        handler = RemoteHandler(
+            "127.0.0.1", 9000, maximum_buffer=10, _reactor=self.reactor
+        )
+        logger = self.get_logger(handler)
+
+        # Send a bunch of useful messages
+        for i in range(0, 20):
+            logger.warning("warn %s" % (i,))
+
+        # Allow the reconnection
+        client, server = connect_logging_client(self.reactor, 0)
+        client.transport.flush()
+
+        # The first five and last five warnings made it through, the debugs and
+        # infos were elided
+        logs = server.data.decode("utf8").splitlines()
+        self.assertEqual(
+            ["warn %s" % (i,) for i in range(5)]
+            + ["warn %s" % (i,) for i in range(15, 20)],
+            logs,
+        )
+
+    def test_cancel_connection(self):
+        """
+        Gracefully handle the connection being cancelled.
+        """
+        handler = RemoteHandler(
+            "127.0.0.1", 9000, maximum_buffer=10, _reactor=self.reactor
+        )
+        logger = self.get_logger(handler)
+
+        # Send a message.
+        logger.info("Hello there, %s!", "wally")
+
+        # Do not accept the connection and shutdown. This causes the pending
+        # connection to be cancelled (and should not raise any exceptions).
+        handler.close()
diff --git a/tests/logging/test_structured.py b/tests/logging/test_structured.py
deleted file mode 100644
index d36f5f426c..0000000000
--- a/tests/logging/test_structured.py
+++ /dev/null
@@ -1,214 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2019 The Matrix.org Foundation C.I.C.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-import logging
-import os
-import os.path
-import shutil
-import sys
-import textwrap
-
-from twisted.logger import Logger, eventAsText, eventsFromJSONLogFile
-
-from synapse.config.logger import setup_logging
-from synapse.logging._structured import setup_structured_logging
-from synapse.logging.context import LoggingContext
-
-from tests.unittest import DEBUG, HomeserverTestCase
-
-
-class FakeBeginner:
-    def beginLoggingTo(self, observers, **kwargs):
-        self.observers = observers
-
-
-class StructuredLoggingTestBase:
-    """
-    Test base that registers a cleanup handler to reset the stdlib log handler
-    to 'unset'.
-    """
-
-    def prepare(self, reactor, clock, hs):
-        def _cleanup():
-            logging.getLogger("synapse").setLevel(logging.NOTSET)
-
-        self.addCleanup(_cleanup)
-
-
-class StructuredLoggingTestCase(StructuredLoggingTestBase, HomeserverTestCase):
-    """
-    Tests for Synapse's structured logging support.
-    """
-
-    def test_output_to_json_round_trip(self):
-        """
-        Synapse logs can be outputted to JSON and then read back again.
-        """
-        temp_dir = self.mktemp()
-        os.mkdir(temp_dir)
-        self.addCleanup(shutil.rmtree, temp_dir)
-
-        json_log_file = os.path.abspath(os.path.join(temp_dir, "out.json"))
-
-        log_config = {
-            "drains": {"jsonfile": {"type": "file_json", "location": json_log_file}}
-        }
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs, self.hs.config, log_config, logBeginner=beginner
-        )
-
-        # Make a logger and send an event
-        logger = Logger(
-            namespace="tests.logging.test_structured", observer=beginner.observers[0]
-        )
-        logger.info("Hello there, {name}!", name="wally")
-
-        # Read the log file and check it has the event we sent
-        with open(json_log_file, "r") as f:
-            logged_events = list(eventsFromJSONLogFile(f))
-        self.assertEqual(len(logged_events), 1)
-
-        # The event pulled from the file should render fine
-        self.assertEqual(
-            eventAsText(logged_events[0], includeTimestamp=False),
-            "[tests.logging.test_structured#info] Hello there, wally!",
-        )
-
-    def test_output_to_text(self):
-        """
-        Synapse logs can be outputted to text.
-        """
-        temp_dir = self.mktemp()
-        os.mkdir(temp_dir)
-        self.addCleanup(shutil.rmtree, temp_dir)
-
-        log_file = os.path.abspath(os.path.join(temp_dir, "out.log"))
-
-        log_config = {"drains": {"file": {"type": "file", "location": log_file}}}
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs, self.hs.config, log_config, logBeginner=beginner
-        )
-
-        # Make a logger and send an event
-        logger = Logger(
-            namespace="tests.logging.test_structured", observer=beginner.observers[0]
-        )
-        logger.info("Hello there, {name}!", name="wally")
-
-        # Read the log file and check it has the event we sent
-        with open(log_file, "r") as f:
-            logged_events = f.read().strip().split("\n")
-        self.assertEqual(len(logged_events), 1)
-
-        # The event pulled from the file should render fine
-        self.assertTrue(
-            logged_events[0].endswith(
-                " - tests.logging.test_structured - INFO - None - Hello there, wally!"
-            )
-        )
-
-    def test_collects_logcontext(self):
-        """
-        Test that log outputs have the attached logging context.
-        """
-        log_config = {"drains": {}}
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        publisher = setup_structured_logging(
-            self.hs, self.hs.config, log_config, logBeginner=beginner
-        )
-
-        logs = []
-
-        publisher.addObserver(logs.append)
-
-        # Make a logger and send an event
-        logger = Logger(
-            namespace="tests.logging.test_structured", observer=beginner.observers[0]
-        )
-
-        with LoggingContext("testcontext", request="somereq"):
-            logger.info("Hello there, {name}!", name="steve")
-
-        self.assertEqual(len(logs), 1)
-        self.assertEqual(logs[0]["request"], "somereq")
-
-
-class StructuredLoggingConfigurationFileTestCase(
-    StructuredLoggingTestBase, HomeserverTestCase
-):
-    def make_homeserver(self, reactor, clock):
-
-        tempdir = self.mktemp()
-        os.mkdir(tempdir)
-        log_config_file = os.path.abspath(os.path.join(tempdir, "log.config.yaml"))
-        self.homeserver_log = os.path.abspath(os.path.join(tempdir, "homeserver.log"))
-
-        config = self.default_config()
-        config["log_config"] = log_config_file
-
-        with open(log_config_file, "w") as f:
-            f.write(
-                textwrap.dedent(
-                    """\
-                    structured: true
-
-                    drains:
-                        file:
-                            type: file_json
-                            location: %s
-                    """
-                    % (self.homeserver_log,)
-                )
-            )
-
-        self.addCleanup(self._sys_cleanup)
-
-        return self.setup_test_homeserver(config=config)
-
-    def _sys_cleanup(self):
-        sys.stdout = sys.__stdout__
-        sys.stderr = sys.__stderr__
-
-    # Do not remove! We need the logging system to be set other than WARNING.
-    @DEBUG
-    def test_log_output(self):
-        """
-        When a structured logging config is given, Synapse will use it.
-        """
-        beginner = FakeBeginner()
-        publisher = setup_logging(self.hs, self.hs.config, logBeginner=beginner)
-
-        # Make a logger and send an event
-        logger = Logger(namespace="tests.logging.test_structured", observer=publisher)
-
-        with LoggingContext("testcontext", request="somereq"):
-            logger.info("Hello there, {name}!", name="steve")
-
-        with open(self.homeserver_log, "r") as f:
-            logged_events = [
-                eventAsText(x, includeTimestamp=False) for x in eventsFromJSONLogFile(f)
-            ]
-
-        logs = "\n".join(logged_events)
-        self.assertTrue("***** STARTING SERVER *****" in logs)
-        self.assertTrue("Hello there, steve!" in logs)
diff --git a/tests/logging/test_terse_json.py b/tests/logging/test_terse_json.py
index 4cf81f7128..73f469b802 100644
--- a/tests/logging/test_terse_json.py
+++ b/tests/logging/test_terse_json.py
@@ -14,57 +14,33 @@
 # limitations under the License.
 
 import json
-from collections import Counter
+import logging
+from io import StringIO
 
-from twisted.logger import Logger
+from synapse.logging._terse_json import JsonFormatter, TerseJsonFormatter
 
-from synapse.logging._structured import setup_structured_logging
-
-from tests.server import connect_client
-from tests.unittest import HomeserverTestCase
-
-from .test_structured import FakeBeginner, StructuredLoggingTestBase
+from tests.logging import LoggerCleanupMixin
+from tests.unittest import TestCase
 
 
-class TerseJSONTCPTestCase(StructuredLoggingTestBase, HomeserverTestCase):
-    def test_log_output(self):
+class TerseJsonTestCase(LoggerCleanupMixin, TestCase):
+    def test_terse_json_output(self):
         """
-        The Terse JSON outputter delivers simplified structured logs over TCP.
+        The Terse JSON formatter converts log messages to JSON.
         """
-        log_config = {
-            "drains": {
-                "tersejson": {
-                    "type": "network_json_terse",
-                    "host": "127.0.0.1",
-                    "port": 8000,
-                }
-            }
-        }
+        output = StringIO()
 
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs, self.hs.config, log_config, logBeginner=beginner
-        )
+        handler = logging.StreamHandler(output)
+        handler.setFormatter(TerseJsonFormatter())
+        logger = self.get_logger(handler)
 
-        logger = Logger(
-            namespace="tests.logging.test_terse_json", observer=beginner.observers[0]
-        )
-        logger.info("Hello there, {name}!", name="wally")
+        logger.info("Hello there, %s!", "wally")
 
-        # Trigger the connection
-        self.pump()
-
-        _, server = connect_client(self.reactor, 0)
-
-        # Trigger data being sent
-        self.pump()
-
-        # One log message, with a single trailing newline
-        logs = server.data.decode("utf8").splitlines()
+        # One log message, with a single trailing newline.
+        data = output.getvalue()
+        logs = data.splitlines()
         self.assertEqual(len(logs), 1)
-        self.assertEqual(server.data.count(b"\n"), 1)
-
+        self.assertEqual(data.count("\n"), 1)
         log = json.loads(logs[0])
 
         # The terse logger should give us these keys.
@@ -72,163 +48,74 @@ class TerseJSONTCPTestCase(StructuredLoggingTestBase, HomeserverTestCase):
             "log",
             "time",
             "level",
-            "log_namespace",
-            "request",
-            "scope",
-            "server_name",
-            "name",
+            "namespace",
         ]
-        self.assertEqual(set(log.keys()), set(expected_log_keys))
+        self.assertCountEqual(log.keys(), expected_log_keys)
+        self.assertEqual(log["log"], "Hello there, wally!")
 
-        # It contains the data we expect.
-        self.assertEqual(log["name"], "wally")
-
-    def test_log_backpressure_debug(self):
+    def test_extra_data(self):
         """
-        When backpressure is hit, DEBUG logs will be shed.
+        Additional information can be included in the structured logging.
         """
-        log_config = {
-            "loggers": {"synapse": {"level": "DEBUG"}},
-            "drains": {
-                "tersejson": {
-                    "type": "network_json_terse",
-                    "host": "127.0.0.1",
-                    "port": 8000,
-                    "maximum_buffer": 10,
-                }
-            },
-        }
+        output = StringIO()
 
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs,
-            self.hs.config,
-            log_config,
-            logBeginner=beginner,
-            redirect_stdlib_logging=False,
+        handler = logging.StreamHandler(output)
+        handler.setFormatter(TerseJsonFormatter())
+        logger = self.get_logger(handler)
+
+        logger.info(
+            "Hello there, %s!", "wally", extra={"foo": "bar", "int": 3, "bool": True}
         )
 
-        logger = Logger(
-            namespace="synapse.logging.test_terse_json", observer=beginner.observers[0]
-        )
+        # One log message, with a single trailing newline.
+        data = output.getvalue()
+        logs = data.splitlines()
+        self.assertEqual(len(logs), 1)
+        self.assertEqual(data.count("\n"), 1)
+        log = json.loads(logs[0])
 
-        # Send some debug messages
-        for i in range(0, 3):
-            logger.debug("debug %s" % (i,))
+        # The terse logger should give us these keys.
+        expected_log_keys = [
+            "log",
+            "time",
+            "level",
+            "namespace",
+            # The additional keys given via extra.
+            "foo",
+            "int",
+            "bool",
+        ]
+        self.assertCountEqual(log.keys(), expected_log_keys)
 
-        # Send a bunch of useful messages
-        for i in range(0, 7):
-            logger.info("test message %s" % (i,))
+        # Check the values of the extra fields.
+        self.assertEqual(log["foo"], "bar")
+        self.assertEqual(log["int"], 3)
+        self.assertIs(log["bool"], True)
 
-        # The last debug message pushes it past the maximum buffer
-        logger.debug("too much debug")
-
-        # Allow the reconnection
-        _, server = connect_client(self.reactor, 0)
-        self.pump()
-
-        # Only the 7 infos made it through, the debugs were elided
-        logs = server.data.splitlines()
-        self.assertEqual(len(logs), 7)
-
-    def test_log_backpressure_info(self):
+    def test_json_output(self):
         """
-        When backpressure is hit, DEBUG and INFO logs will be shed.
+        The Terse JSON formatter converts log messages to JSON.
         """
-        log_config = {
-            "loggers": {"synapse": {"level": "DEBUG"}},
-            "drains": {
-                "tersejson": {
-                    "type": "network_json_terse",
-                    "host": "127.0.0.1",
-                    "port": 8000,
-                    "maximum_buffer": 10,
-                }
-            },
-        }
+        output = StringIO()
 
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs,
-            self.hs.config,
-            log_config,
-            logBeginner=beginner,
-            redirect_stdlib_logging=False,
-        )
+        handler = logging.StreamHandler(output)
+        handler.setFormatter(JsonFormatter())
+        logger = self.get_logger(handler)
 
-        logger = Logger(
-            namespace="synapse.logging.test_terse_json", observer=beginner.observers[0]
-        )
+        logger.info("Hello there, %s!", "wally")
 
-        # Send some debug messages
-        for i in range(0, 3):
-            logger.debug("debug %s" % (i,))
+        # One log message, with a single trailing newline.
+        data = output.getvalue()
+        logs = data.splitlines()
+        self.assertEqual(len(logs), 1)
+        self.assertEqual(data.count("\n"), 1)
+        log = json.loads(logs[0])
 
-        # Send a bunch of useful messages
-        for i in range(0, 10):
-            logger.warn("test warn %s" % (i,))
-
-        # Send a bunch of info messages
-        for i in range(0, 3):
-            logger.info("test message %s" % (i,))
-
-        # The last debug message pushes it past the maximum buffer
-        logger.debug("too much debug")
-
-        # Allow the reconnection
-        client, server = connect_client(self.reactor, 0)
-        self.pump()
-
-        # The 10 warnings made it through, the debugs and infos were elided
-        logs = list(map(json.loads, server.data.decode("utf8").splitlines()))
-        self.assertEqual(len(logs), 10)
-
-        self.assertEqual(Counter([x["level"] for x in logs]), {"WARN": 10})
-
-    def test_log_backpressure_cut_middle(self):
-        """
-        When backpressure is hit, and no more DEBUG and INFOs cannot be culled,
-        it will cut the middle messages out.
-        """
-        log_config = {
-            "loggers": {"synapse": {"level": "DEBUG"}},
-            "drains": {
-                "tersejson": {
-                    "type": "network_json_terse",
-                    "host": "127.0.0.1",
-                    "port": 8000,
-                    "maximum_buffer": 10,
-                }
-            },
-        }
-
-        # Begin the logger with our config
-        beginner = FakeBeginner()
-        setup_structured_logging(
-            self.hs,
-            self.hs.config,
-            log_config,
-            logBeginner=beginner,
-            redirect_stdlib_logging=False,
-        )
-
-        logger = Logger(
-            namespace="synapse.logging.test_terse_json", observer=beginner.observers[0]
-        )
-
-        # Send a bunch of useful messages
-        for i in range(0, 20):
-            logger.warn("test warn", num=i)
-
-        # Allow the reconnection
-        client, server = connect_client(self.reactor, 0)
-        self.pump()
-
-        # The first five and last five warnings made it through, the debugs and
-        # infos were elided
-        logs = list(map(json.loads, server.data.decode("utf8").splitlines()))
-        self.assertEqual(len(logs), 10)
-        self.assertEqual(Counter([x["level"] for x in logs]), {"WARN": 10})
-        self.assertEqual([0, 1, 2, 3, 4, 15, 16, 17, 18, 19], [x["num"] for x in logs])
+        # The terse logger should give us these keys.
+        expected_log_keys = [
+            "log",
+            "level",
+            "namespace",
+        ]
+        self.assertCountEqual(log.keys(), expected_log_keys)
+        self.assertEqual(log["log"], "Hello there, wally!")
diff --git a/tests/module_api/test_api.py b/tests/module_api/test_api.py
index ccbb82f6a3..27206ca3db 100644
--- a/tests/module_api/test_api.py
+++ b/tests/module_api/test_api.py
@@ -15,7 +15,6 @@
 from mock import Mock
 
 from synapse.events import EventBase
-from synapse.module_api import ModuleApi
 from synapse.rest import admin
 from synapse.rest.client.v1 import login, room
 from synapse.types import create_requester
@@ -32,7 +31,7 @@ class ModuleApiTestCase(HomeserverTestCase):
 
     def prepare(self, reactor, clock, homeserver):
         self.store = homeserver.get_datastore()
-        self.module_api = ModuleApi(homeserver, homeserver.get_auth_handler())
+        self.module_api = homeserver.get_module_api()
         self.event_creation_handler = homeserver.get_event_creation_handler()
 
     def test_can_register_user(self):
@@ -95,9 +94,13 @@ class ModuleApiTestCase(HomeserverTestCase):
         self.assertFalse(hasattr(event, "state_key"))
         self.assertDictEqual(event.content, content)
 
+        expected_requester = create_requester(
+            user_id, authenticated_entity=self.hs.hostname
+        )
+
         # Check that the event was sent
         self.event_creation_handler.create_and_send_nonmember_event.assert_called_with(
-            create_requester(user_id), event_dict, ratelimit=False,
+            expected_requester, event_dict, ratelimit=False, ignore_shadow_ban=True,
         )
 
         # Create and send a state event
@@ -126,7 +129,7 @@ class ModuleApiTestCase(HomeserverTestCase):
 
         # Check that the event was sent
         self.event_creation_handler.create_and_send_nonmember_event.assert_called_with(
-            create_requester(user_id),
+            expected_requester,
             {
                 "type": "m.room.power_levels",
                 "content": content,
@@ -135,6 +138,7 @@ class ModuleApiTestCase(HomeserverTestCase):
                 "state_key": "",
             },
             ratelimit=False,
+            ignore_shadow_ban=True,
         )
 
         # Check that we can't send membership events
diff --git a/tests/push/test_email.py b/tests/push/test_email.py
index 3224568640..bcdcafa5a9 100644
--- a/tests/push/test_email.py
+++ b/tests/push/test_email.py
@@ -100,7 +100,7 @@ class EmailPusherTests(HomeserverTestCase):
         user_tuple = self.get_success(
             self.hs.get_datastore().get_user_by_access_token(self.access_token)
         )
-        token_id = user_tuple["token_id"]
+        token_id = user_tuple.token_id
 
         self.pusher = self.get_success(
             self.hs.get_pusherpool().add_pusher(
@@ -131,6 +131,35 @@ class EmailPusherTests(HomeserverTestCase):
         # We should get emailed about that message
         self._check_for_mail()
 
+    def test_invite_sends_email(self):
+        # Create a room and invite the user to it
+        room = self.helper.create_room_as(self.others[0].id, tok=self.others[0].token)
+        self.helper.invite(
+            room=room,
+            src=self.others[0].id,
+            tok=self.others[0].token,
+            targ=self.user_id,
+        )
+
+        # We should get emailed about the invite
+        self._check_for_mail()
+
+    def test_invite_to_empty_room_sends_email(self):
+        # Create a room and invite the user to it
+        room = self.helper.create_room_as(self.others[0].id, tok=self.others[0].token)
+        self.helper.invite(
+            room=room,
+            src=self.others[0].id,
+            tok=self.others[0].token,
+            targ=self.user_id,
+        )
+
+        # Then have the original user leave
+        self.helper.leave(room, self.others[0].id, tok=self.others[0].token)
+
+        # We should get emailed about the invite
+        self._check_for_mail()
+
     def test_multiple_members_email(self):
         # We want to test multiple notifications, so we pause processing of push
         # while we send messages.
@@ -158,8 +187,21 @@ class EmailPusherTests(HomeserverTestCase):
         # We should get emailed about those messages
         self._check_for_mail()
 
+    def test_encrypted_message(self):
+        room = self.helper.create_room_as(self.user_id, tok=self.access_token)
+        self.helper.invite(
+            room=room, src=self.user_id, tok=self.access_token, targ=self.others[0].id
+        )
+        self.helper.join(room=room, user=self.others[0].id, tok=self.others[0].token)
+
+        # The other user sends some messages
+        self.helper.send_event(room, "m.room.encrypted", {}, tok=self.others[0].token)
+
+        # We should get emailed about that message
+        self._check_for_mail()
+
     def _check_for_mail(self):
-        "Check that the user receives an email notification"
+        """Check that the user receives an email notification"""
 
         # Get the stream ordering before it gets sent
         pushers = self.get_success(
diff --git a/tests/push/test_http.py b/tests/push/test_http.py
index 2f56cacc7a..cd46c485dd 100644
--- a/tests/push/test_http.py
+++ b/tests/push/test_http.py
@@ -12,7 +12,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 from mock import Mock
 
 from twisted.internet.defer import Deferred
@@ -20,8 +19,9 @@ from twisted.internet.defer import Deferred
 import synapse.rest.admin
 from synapse.logging.context import make_deferred_yieldable
 from synapse.rest.client.v1 import login, room
+from synapse.rest.client.v2_alpha import receipts
 
-from tests.unittest import HomeserverTestCase
+from tests.unittest import HomeserverTestCase, override_config
 
 
 class HTTPPusherTests(HomeserverTestCase):
@@ -29,6 +29,7 @@ class HTTPPusherTests(HomeserverTestCase):
         synapse.rest.admin.register_servlets_for_client_rest_resource,
         room.register_servlets,
         login.register_servlets,
+        receipts.register_servlets,
     ]
     user_id = True
     hijack_auth = False
@@ -69,7 +70,7 @@ class HTTPPusherTests(HomeserverTestCase):
         user_tuple = self.get_success(
             self.hs.get_datastore().get_user_by_access_token(access_token)
         )
-        token_id = user_tuple["token_id"]
+        token_id = user_tuple.token_id
 
         self.get_success(
             self.hs.get_pusherpool().add_pusher(
@@ -181,7 +182,7 @@ class HTTPPusherTests(HomeserverTestCase):
         user_tuple = self.get_success(
             self.hs.get_datastore().get_user_by_access_token(access_token)
         )
-        token_id = user_tuple["token_id"]
+        token_id = user_tuple.token_id
 
         self.get_success(
             self.hs.get_pusherpool().add_pusher(
@@ -297,7 +298,7 @@ class HTTPPusherTests(HomeserverTestCase):
         user_tuple = self.get_success(
             self.hs.get_datastore().get_user_by_access_token(access_token)
         )
-        token_id = user_tuple["token_id"]
+        token_id = user_tuple.token_id
 
         self.get_success(
             self.hs.get_pusherpool().add_pusher(
@@ -379,7 +380,7 @@ class HTTPPusherTests(HomeserverTestCase):
         user_tuple = self.get_success(
             self.hs.get_datastore().get_user_by_access_token(access_token)
         )
-        token_id = user_tuple["token_id"]
+        token_id = user_tuple.token_id
 
         self.get_success(
             self.hs.get_pusherpool().add_pusher(
@@ -452,7 +453,7 @@ class HTTPPusherTests(HomeserverTestCase):
         user_tuple = self.get_success(
             self.hs.get_datastore().get_user_by_access_token(access_token)
         )
-        token_id = user_tuple["token_id"]
+        token_id = user_tuple.token_id
 
         self.get_success(
             self.hs.get_pusherpool().add_pusher(
@@ -499,3 +500,161 @@ class HTTPPusherTests(HomeserverTestCase):
 
         # check that this is high-priority
         self.assertEqual(self.push_attempts[1][2]["notification"]["prio"], "high")
+
+    def test_push_unread_count_group_by_room(self):
+        """
+        The HTTP pusher will group unread count by number of unread rooms.
+        """
+        # Carry out common push count tests and setup
+        self._test_push_unread_count()
+
+        # Carry out our option-value specific test
+        #
+        # This push should still only contain an unread count of 1 (for 1 unread room)
+        self.assertEqual(
+            self.push_attempts[5][2]["notification"]["counts"]["unread"], 1
+        )
+
+    @override_config({"push": {"group_unread_count_by_room": False}})
+    def test_push_unread_count_message_count(self):
+        """
+        The HTTP pusher will send the total unread message count.
+        """
+        # Carry out common push count tests and setup
+        self._test_push_unread_count()
+
+        # Carry out our option-value specific test
+        #
+        # We're counting every unread message, so there should now be 4 since the
+        # last read receipt
+        self.assertEqual(
+            self.push_attempts[5][2]["notification"]["counts"]["unread"], 4
+        )
+
+    def _test_push_unread_count(self):
+        """
+        Tests that the correct unread count appears in sent push notifications
+
+        Note that:
+        * Sending messages will cause push notifications to go out to relevant users
+        * Sending a read receipt will cause a "badge update" notification to go out to
+          the user that sent the receipt
+        """
+        # Register the user who gets notified
+        user_id = self.register_user("user", "pass")
+        access_token = self.login("user", "pass")
+
+        # Register the user who sends the message
+        other_user_id = self.register_user("other_user", "pass")
+        other_access_token = self.login("other_user", "pass")
+
+        # Create a room (as other_user)
+        room_id = self.helper.create_room_as(other_user_id, tok=other_access_token)
+
+        # The user to get notified joins
+        self.helper.join(room=room_id, user=user_id, tok=access_token)
+
+        # Register the pusher
+        user_tuple = self.get_success(
+            self.hs.get_datastore().get_user_by_access_token(access_token)
+        )
+        token_id = user_tuple.token_id
+
+        self.get_success(
+            self.hs.get_pusherpool().add_pusher(
+                user_id=user_id,
+                access_token=token_id,
+                kind="http",
+                app_id="m.http",
+                app_display_name="HTTP Push Notifications",
+                device_display_name="pushy push",
+                pushkey="a@example.com",
+                lang=None,
+                data={"url": "example.com"},
+            )
+        )
+
+        # Send a message
+        response = self.helper.send(
+            room_id, body="Hello there!", tok=other_access_token
+        )
+        # To get an unread count, the user who is getting notified has to have a read
+        # position in the room. We'll set the read position to this event in a moment
+        first_message_event_id = response["event_id"]
+
+        # Advance time a bit (so the pusher will register something has happened) and
+        # make the push succeed
+        self.push_attempts[0][0].callback({})
+        self.pump()
+
+        # Check our push made it
+        self.assertEqual(len(self.push_attempts), 1)
+        self.assertEqual(self.push_attempts[0][1], "example.com")
+
+        # Check that the unread count for the room is 0
+        #
+        # The unread count is zero as the user has no read receipt in the room yet
+        self.assertEqual(
+            self.push_attempts[0][2]["notification"]["counts"]["unread"], 0
+        )
+
+        # Now set the user's read receipt position to the first event
+        #
+        # This will actually trigger a new notification to be sent out so that
+        # even if the user does not receive another message, their unread
+        # count goes down
+        request, channel = self.make_request(
+            "POST",
+            "/rooms/%s/receipt/m.read/%s" % (room_id, first_message_event_id),
+            {},
+            access_token=access_token,
+        )
+        self.assertEqual(channel.code, 200, channel.json_body)
+
+        # Advance time and make the push succeed
+        self.push_attempts[1][0].callback({})
+        self.pump()
+
+        # Unread count is still zero as we've read the only message in the room
+        self.assertEqual(len(self.push_attempts), 2)
+        self.assertEqual(
+            self.push_attempts[1][2]["notification"]["counts"]["unread"], 0
+        )
+
+        # Send another message
+        self.helper.send(
+            room_id, body="How's the weather today?", tok=other_access_token
+        )
+
+        # Advance time and make the push succeed
+        self.push_attempts[2][0].callback({})
+        self.pump()
+
+        # This push should contain an unread count of 1 as there's now been one
+        # message since our last read receipt
+        self.assertEqual(len(self.push_attempts), 3)
+        self.assertEqual(
+            self.push_attempts[2][2]["notification"]["counts"]["unread"], 1
+        )
+
+        # Since we're grouping by room, sending more messages shouldn't increase the
+        # unread count, as they're all being sent in the same room
+        self.helper.send(room_id, body="Hello?", tok=other_access_token)
+
+        # Advance time and make the push succeed
+        self.pump()
+        self.push_attempts[3][0].callback({})
+
+        self.helper.send(room_id, body="Hello??", tok=other_access_token)
+
+        # Advance time and make the push succeed
+        self.pump()
+        self.push_attempts[4][0].callback({})
+
+        self.helper.send(room_id, body="HELLO???", tok=other_access_token)
+
+        # Advance time and make the push succeed
+        self.pump()
+        self.push_attempts[5][0].callback({})
+
+        self.assertEqual(len(self.push_attempts), 6)
diff --git a/tests/replication/_base.py b/tests/replication/_base.py
index ae60874ec3..295c5d58a6 100644
--- a/tests/replication/_base.py
+++ b/tests/replication/_base.py
@@ -12,13 +12,13 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 import logging
 from typing import Any, Callable, List, Optional, Tuple
 
 import attr
 
 from twisted.internet.interfaces import IConsumer, IPullProducer, IReactorTime
+from twisted.internet.protocol import Protocol
 from twisted.internet.task import LoopingCall
 from twisted.web.http import HTTPChannel
 
@@ -27,7 +27,7 @@ from synapse.app.generic_worker import (
     GenericWorkerServer,
 )
 from synapse.http.server import JsonResource
-from synapse.http.site import SynapseRequest
+from synapse.http.site import SynapseRequest, SynapseSite
 from synapse.replication.http import ReplicationRestResource, streams
 from synapse.replication.tcp.handler import ReplicationCommandHandler
 from synapse.replication.tcp.protocol import ClientReplicationStreamProtocol
@@ -36,7 +36,12 @@ from synapse.server import HomeServer
 from synapse.util import Clock
 
 from tests import unittest
-from tests.server import FakeTransport, render
+from tests.server import FakeTransport
+
+try:
+    import hiredis
+except ImportError:
+    hiredis = None
 
 logger = logging.getLogger(__name__)
 
@@ -44,6 +49,11 @@ logger = logging.getLogger(__name__)
 class BaseStreamTestCase(unittest.HomeserverTestCase):
     """Base class for tests of the replication streams"""
 
+    # hiredis is an optional dependency so we don't want to require it for running
+    # the tests.
+    if not hiredis:
+        skip = "Requires hiredis"
+
     servlets = [
         streams.register_servlets,
     ]
@@ -58,7 +68,7 @@ class BaseStreamTestCase(unittest.HomeserverTestCase):
         self.reactor.lookups["testserv"] = "1.2.3.4"
         self.worker_hs = self.setup_test_homeserver(
             http_client=None,
-            homeserverToUse=GenericWorkerServer,
+            homeserver_to_use=GenericWorkerServer,
             config=self._get_worker_hs_config(),
             reactor=self.reactor,
         )
@@ -68,7 +78,7 @@ class BaseStreamTestCase(unittest.HomeserverTestCase):
         self.worker_hs.get_datastore().db_pool = hs.get_datastore().db_pool
 
         self.test_handler = self._build_replication_data_handler()
-        self.worker_hs.replication_data_handler = self.test_handler
+        self.worker_hs._replication_data_handler = self.test_handler
 
         repl_handler = ReplicationCommandHandler(self.worker_hs)
         self.client = ClientReplicationStreamProtocol(
@@ -197,23 +207,41 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         self.server_factory = ReplicationStreamProtocolFactory(self.hs)
         self.streamer = self.hs.get_replication_streamer()
 
+        # Fake in memory Redis server that servers can connect to.
+        self._redis_server = FakeRedisPubSubServer()
+
         store = self.hs.get_datastore()
         self.database_pool = store.db_pool
 
         self.reactor.lookups["testserv"] = "1.2.3.4"
+        self.reactor.lookups["localhost"] = "127.0.0.1"
 
-        self._worker_hs_to_resource = {}
+        # A map from a HS instance to the associated HTTP Site to use for
+        # handling inbound HTTP requests to that instance.
+        self._hs_to_site = {self.hs: self.site}
+
+        if self.hs.config.redis.redis_enabled:
+            # Handle attempts to connect to fake redis server.
+            self.reactor.add_tcp_client_callback(
+                "localhost", 6379, self.connect_any_redis_attempts,
+            )
+
+            self.hs.get_tcp_replication().start_replication(self.hs)
 
         # When we see a connection attempt to the master replication listener we
         # automatically set up the connection. This is so that tests don't
         # manually have to go and explicitly set it up each time (plus sometimes
         # it is impossible to write the handling explicitly in the tests).
+        #
+        # Register the master replication listener:
         self.reactor.add_tcp_client_callback(
-            "1.2.3.4", 8765, self._handle_http_replication_attempt
+            "1.2.3.4",
+            8765,
+            lambda: self._handle_http_replication_attempt(self.hs, 8765),
         )
 
-    def create_test_json_resource(self):
-        """Overrides `HomeserverTestCase.create_test_json_resource`.
+    def create_test_resource(self):
+        """Overrides `HomeserverTestCase.create_test_resource`.
         """
         # We override this so that it automatically registers all the HTTP
         # replication servlets, without having to explicitly do that in all
@@ -247,34 +275,69 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         config.update(extra_config)
 
         worker_hs = self.setup_test_homeserver(
-            homeserverToUse=GenericWorkerServer,
+            homeserver_to_use=GenericWorkerServer,
             config=config,
             reactor=self.reactor,
-            **kwargs
+            **kwargs,
         )
 
+        # If the instance is in the `instance_map` config then workers may try
+        # and send HTTP requests to it, so we register it with
+        # `_handle_http_replication_attempt` like we do with the master HS.
+        instance_name = worker_hs.get_instance_name()
+        instance_loc = worker_hs.config.worker.instance_map.get(instance_name)
+        if instance_loc:
+            # Ensure the host is one that has a fake DNS entry.
+            if instance_loc.host not in self.reactor.lookups:
+                raise Exception(
+                    "Host does not have an IP for instance_map[%r].host = %r"
+                    % (instance_name, instance_loc.host,)
+                )
+
+            self.reactor.add_tcp_client_callback(
+                self.reactor.lookups[instance_loc.host],
+                instance_loc.port,
+                lambda: self._handle_http_replication_attempt(
+                    worker_hs, instance_loc.port
+                ),
+            )
+
         store = worker_hs.get_datastore()
         store.db_pool._db_pool = self.database_pool._db_pool
 
-        repl_handler = ReplicationCommandHandler(worker_hs)
-        client = ClientReplicationStreamProtocol(
-            worker_hs, "client", "test", self.clock, repl_handler,
-        )
-        server = self.server_factory.buildProtocol(None)
+        # Set up TCP replication between master and the new worker if we don't
+        # have Redis support enabled.
+        if not worker_hs.config.redis_enabled:
+            repl_handler = ReplicationCommandHandler(worker_hs)
+            client = ClientReplicationStreamProtocol(
+                worker_hs, "client", "test", self.clock, repl_handler,
+            )
+            server = self.server_factory.buildProtocol(None)
 
-        client_transport = FakeTransport(server, self.reactor)
-        client.makeConnection(client_transport)
+            client_transport = FakeTransport(server, self.reactor)
+            client.makeConnection(client_transport)
 
-        server_transport = FakeTransport(client, self.reactor)
-        server.makeConnection(server_transport)
+            server_transport = FakeTransport(client, self.reactor)
+            server.makeConnection(server_transport)
 
         # Set up a resource for the worker
-        resource = ReplicationRestResource(self.hs)
+        resource = ReplicationRestResource(worker_hs)
 
         for servlet in self.servlets:
             servlet(worker_hs, resource)
 
-        self._worker_hs_to_resource[worker_hs] = resource
+        self._hs_to_site[worker_hs] = SynapseSite(
+            logger_name="synapse.access.http.fake",
+            site_tag="{}-{}".format(
+                worker_hs.config.server.server_name, worker_hs.get_instance_name()
+            ),
+            config=worker_hs.config.server.listeners[0],
+            resource=resource,
+            server_version_string="1",
+        )
+
+        if worker_hs.config.redis.redis_enabled:
+            worker_hs.get_tcp_replication().start_replication(worker_hs)
 
         return worker_hs
 
@@ -284,9 +347,6 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         config["worker_replication_http_port"] = "8765"
         return config
 
-    def render_on_worker(self, worker_hs: HomeServer, request: SynapseRequest):
-        render(request, self._worker_hs_to_resource[worker_hs], self.reactor)
-
     def replicate(self):
         """Tell the master side of replication that something has happened, and then
         wait for the replication to occur.
@@ -294,9 +354,9 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         self.streamer.on_notifier_poke()
         self.pump()
 
-    def _handle_http_replication_attempt(self):
-        """Handles a connection attempt to the master replication HTTP
-        listener.
+    def _handle_http_replication_attempt(self, hs, repl_port):
+        """Handles a connection attempt to the given HS replication HTTP
+        listener on the given port.
         """
 
         # We should have at least one outbound connection attempt, where the
@@ -305,7 +365,7 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         self.assertGreaterEqual(len(clients), 1)
         (host, port, client_factory, _timeout, _bindAddress) = clients.pop()
         self.assertEqual(host, "1.2.3.4")
-        self.assertEqual(port, 8765)
+        self.assertEqual(port, repl_port)
 
         # Set up client side protocol
         client_protocol = client_factory.buildProtocol(None)
@@ -315,7 +375,7 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         # Set up the server side protocol
         channel = _PushHTTPChannel(self.reactor)
         channel.requestFactory = request_factory
-        channel.site = self.site
+        channel.site = self._hs_to_site[hs]
 
         # Connect client to server and vice versa.
         client_to_server_transport = FakeTransport(
@@ -333,6 +393,32 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         # inside `connecTCP` before the connection has been passed back to the
         # code that requested the TCP connection.
 
+    def connect_any_redis_attempts(self):
+        """If redis is enabled we need to deal with workers connecting to a
+        redis server. We don't want to use a real Redis server so we use a
+        fake one.
+        """
+        clients = self.reactor.tcpClients
+        self.assertEqual(len(clients), 1)
+        (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)
+        self.assertEqual(host, "localhost")
+        self.assertEqual(port, 6379)
+
+        client_protocol = client_factory.buildProtocol(None)
+        server_protocol = self._redis_server.buildProtocol(None)
+
+        client_to_server_transport = FakeTransport(
+            server_protocol, self.reactor, client_protocol
+        )
+        client_protocol.makeConnection(client_to_server_transport)
+
+        server_to_client_transport = FakeTransport(
+            client_protocol, self.reactor, server_protocol
+        )
+        server_protocol.makeConnection(server_to_client_transport)
+
+        return client_to_server_transport, server_to_client_transport
+
 
 class TestReplicationDataHandler(GenericWorkerReplicationHandler):
     """Drop-in for ReplicationDataHandler which just collects RDATA rows"""
@@ -467,3 +553,105 @@ class _PullToPushProducer:
                 pass
 
             self.stopProducing()
+
+
+class FakeRedisPubSubServer:
+    """A fake Redis server for pub/sub.
+    """
+
+    def __init__(self):
+        self._subscribers = set()
+
+    def add_subscriber(self, conn):
+        """A connection has called SUBSCRIBE
+        """
+        self._subscribers.add(conn)
+
+    def remove_subscriber(self, conn):
+        """A connection has called UNSUBSCRIBE
+        """
+        self._subscribers.discard(conn)
+
+    def publish(self, conn, channel, msg) -> int:
+        """A connection want to publish a message to subscribers.
+        """
+        for sub in self._subscribers:
+            sub.send(["message", channel, msg])
+
+        return len(self._subscribers)
+
+    def buildProtocol(self, addr):
+        return FakeRedisPubSubProtocol(self)
+
+
+class FakeRedisPubSubProtocol(Protocol):
+    """A connection from a client talking to the fake Redis server.
+    """
+
+    def __init__(self, server: FakeRedisPubSubServer):
+        self._server = server
+        self._reader = hiredis.Reader()
+
+    def dataReceived(self, data):
+        self._reader.feed(data)
+
+        # We might get multiple messages in one packet.
+        while True:
+            msg = self._reader.gets()
+
+            if msg is False:
+                # No more messages.
+                return
+
+            if not isinstance(msg, list):
+                # Inbound commands should always be a list
+                raise Exception("Expected redis list")
+
+            self.handle_command(msg[0], *msg[1:])
+
+    def handle_command(self, command, *args):
+        """Received a Redis command from the client.
+        """
+
+        # We currently only support pub/sub.
+        if command == b"PUBLISH":
+            channel, message = args
+            num_subscribers = self._server.publish(self, channel, message)
+            self.send(num_subscribers)
+        elif command == b"SUBSCRIBE":
+            (channel,) = args
+            self._server.add_subscriber(self)
+            self.send(["subscribe", channel, 1])
+        else:
+            raise Exception("Unknown command")
+
+    def send(self, msg):
+        """Send a message back to the client.
+        """
+        raw = self.encode(msg).encode("utf-8")
+
+        self.transport.write(raw)
+        self.transport.flush()
+
+    def encode(self, obj):
+        """Encode an object to its Redis format.
+
+        Supports: strings/bytes, integers and list/tuples.
+        """
+
+        if isinstance(obj, bytes):
+            # We assume bytes are just unicode strings.
+            obj = obj.decode("utf-8")
+
+        if isinstance(obj, str):
+            return "${len}\r\n{str}\r\n".format(len=len(obj), str=obj)
+        if isinstance(obj, int):
+            return ":{val}\r\n".format(val=obj)
+        if isinstance(obj, (list, tuple)):
+            items = "".join(self.encode(a) for a in obj)
+            return "*{len}\r\n{items}".format(len=len(obj), items=items)
+
+        raise Exception("Unrecognized type for encoding redis: %r: %r", type(obj), obj)
+
+    def connectionLost(self, reason):
+        self._server.remove_subscriber(self)
diff --git a/tests/replication/tcp/streams/test_events.py b/tests/replication/tcp/streams/test_events.py
index c9998e88e6..bad0df08cf 100644
--- a/tests/replication/tcp/streams/test_events.py
+++ b/tests/replication/tcp/streams/test_events.py
@@ -449,7 +449,7 @@ class EventsStreamTestCase(BaseStreamTestCase):
                 sender=sender,
                 type="test_event",
                 content={"body": body},
-                **kwargs
+                **kwargs,
             )
         )
 
diff --git a/tests/replication/test_client_reader_shard.py b/tests/replication/test_client_reader_shard.py
index 86c03fd89c..96801db473 100644
--- a/tests/replication/test_client_reader_shard.py
+++ b/tests/replication/test_client_reader_shard.py
@@ -20,7 +20,7 @@ from synapse.rest.client.v2_alpha import register
 
 from tests.replication._base import BaseMultiWorkerStreamTestCase
 from tests.rest.client.v2_alpha.test_auth import DummyRecaptchaChecker
-from tests.server import FakeChannel
+from tests.server import FakeChannel, make_request
 
 logger = logging.getLogger(__name__)
 
@@ -46,23 +46,28 @@ class ClientReaderTestCase(BaseMultiWorkerStreamTestCase):
         """Test that registration works when using a single client reader worker.
         """
         worker_hs = self.make_worker_hs("synapse.app.client_reader")
+        site = self._hs_to_site[worker_hs]
 
-        request_1, channel_1 = self.make_request(
+        request_1, channel_1 = make_request(
+            self.reactor,
+            site,
             "POST",
             "register",
             {"username": "user", "type": "m.login.password", "password": "bar"},
         )  # type: SynapseRequest, FakeChannel
-        self.render_on_worker(worker_hs, request_1)
         self.assertEqual(request_1.code, 401)
 
         # Grab the session
         session = channel_1.json_body["session"]
 
         # also complete the dummy auth
-        request_2, channel_2 = self.make_request(
-            "POST", "register", {"auth": {"session": session, "type": "m.login.dummy"}}
+        request_2, channel_2 = make_request(
+            self.reactor,
+            site,
+            "POST",
+            "register",
+            {"auth": {"session": session, "type": "m.login.dummy"}},
         )  # type: SynapseRequest, FakeChannel
-        self.render_on_worker(worker_hs, request_2)
         self.assertEqual(request_2.code, 200)
 
         # We're given a registered user.
@@ -74,22 +79,28 @@ class ClientReaderTestCase(BaseMultiWorkerStreamTestCase):
         worker_hs_1 = self.make_worker_hs("synapse.app.client_reader")
         worker_hs_2 = self.make_worker_hs("synapse.app.client_reader")
 
-        request_1, channel_1 = self.make_request(
+        site_1 = self._hs_to_site[worker_hs_1]
+        request_1, channel_1 = make_request(
+            self.reactor,
+            site_1,
             "POST",
             "register",
             {"username": "user", "type": "m.login.password", "password": "bar"},
         )  # type: SynapseRequest, FakeChannel
-        self.render_on_worker(worker_hs_1, request_1)
         self.assertEqual(request_1.code, 401)
 
         # Grab the session
         session = channel_1.json_body["session"]
 
         # also complete the dummy auth
-        request_2, channel_2 = self.make_request(
-            "POST", "register", {"auth": {"session": session, "type": "m.login.dummy"}}
+        site_2 = self._hs_to_site[worker_hs_2]
+        request_2, channel_2 = make_request(
+            self.reactor,
+            site_2,
+            "POST",
+            "register",
+            {"auth": {"session": session, "type": "m.login.dummy"}},
         )  # type: SynapseRequest, FakeChannel
-        self.render_on_worker(worker_hs_2, request_2)
         self.assertEqual(request_2.code, 200)
 
         # We're given a registered user.
diff --git a/tests/replication/test_federation_ack.py b/tests/replication/test_federation_ack.py
index 23be1167a3..1853667558 100644
--- a/tests/replication/test_federation_ack.py
+++ b/tests/replication/test_federation_ack.py
@@ -31,7 +31,7 @@ class FederationAckTestCase(HomeserverTestCase):
         return config
 
     def make_homeserver(self, reactor, clock):
-        hs = self.setup_test_homeserver(homeserverToUse=GenericWorkerServer)
+        hs = self.setup_test_homeserver(homeserver_to_use=GenericWorkerServer)
 
         return hs
 
diff --git a/tests/replication/test_federation_sender_shard.py b/tests/replication/test_federation_sender_shard.py
index 1d7edee5ba..779745ae9d 100644
--- a/tests/replication/test_federation_sender_shard.py
+++ b/tests/replication/test_federation_sender_shard.py
@@ -207,7 +207,7 @@ class FederationSenderTestCase(BaseMultiWorkerStreamTestCase):
     def create_room_with_remote_server(self, user, token, remote_server="other_server"):
         room = self.helper.create_room_as(user, tok=token)
         store = self.hs.get_datastore()
-        federation = self.hs.get_handlers().federation_handler
+        federation = self.hs.get_federation_handler()
 
         prev_event_ids = self.get_success(store.get_latest_event_ids_in_room(room))
         room_version = self.get_success(store.get_room_version(room))
@@ -226,7 +226,7 @@ class FederationSenderTestCase(BaseMultiWorkerStreamTestCase):
         }
 
         builder = factory.for_room_version(room_version, event_dict)
-        join_event = self.get_success(builder.build(prev_event_ids))
+        join_event = self.get_success(builder.build(prev_event_ids, None))
 
         self.get_success(federation.on_send_join_request(remote_server, join_event))
         self.replicate()
diff --git a/tests/replication/test_multi_media_repo.py b/tests/replication/test_multi_media_repo.py
new file mode 100644
index 0000000000..48b574ccbe
--- /dev/null
+++ b/tests/replication/test_multi_media_repo.py
@@ -0,0 +1,279 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+import os
+from binascii import unhexlify
+from typing import Tuple
+
+from twisted.internet.protocol import Factory
+from twisted.protocols.tls import TLSMemoryBIOFactory
+from twisted.web.http import HTTPChannel
+from twisted.web.server import Request
+
+from synapse.rest import admin
+from synapse.rest.client.v1 import login
+from synapse.server import HomeServer
+
+from tests.http import TestServerTLSConnectionFactory, get_test_ca_cert_file
+from tests.replication._base import BaseMultiWorkerStreamTestCase
+from tests.server import FakeChannel, FakeSite, FakeTransport, make_request
+
+logger = logging.getLogger(__name__)
+
+test_server_connection_factory = None
+
+
+class MediaRepoShardTestCase(BaseMultiWorkerStreamTestCase):
+    """Checks running multiple media repos work correctly.
+    """
+
+    servlets = [
+        admin.register_servlets_for_client_rest_resource,
+        login.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.user_id = self.register_user("user", "pass")
+        self.access_token = self.login("user", "pass")
+
+        self.reactor.lookups["example.com"] = "127.0.0.2"
+
+    def default_config(self):
+        conf = super().default_config()
+        conf["federation_custom_ca_list"] = [get_test_ca_cert_file()]
+        return conf
+
+    def _get_media_req(
+        self, hs: HomeServer, target: str, media_id: str
+    ) -> Tuple[FakeChannel, Request]:
+        """Request some remote media from the given HS by calling the download
+        API.
+
+        This then triggers an outbound request from the HS to the target.
+
+        Returns:
+            The channel for the *client* request and the *outbound* request for
+            the media which the caller should respond to.
+        """
+        resource = hs.get_media_repository_resource().children[b"download"]
+        _, channel = make_request(
+            self.reactor,
+            FakeSite(resource),
+            "GET",
+            "/{}/{}".format(target, media_id),
+            shorthand=False,
+            access_token=self.access_token,
+            await_result=False,
+        )
+        self.pump()
+
+        clients = self.reactor.tcpClients
+        self.assertGreaterEqual(len(clients), 1)
+        (host, port, client_factory, _timeout, _bindAddress) = clients.pop()
+
+        # build the test server
+        server_tls_protocol = _build_test_server(get_connection_factory())
+
+        # now, tell the client protocol factory to build the client protocol (it will be a
+        # _WrappingProtocol, around a TLSMemoryBIOProtocol, around an
+        # HTTP11ClientProtocol) and wire the output of said protocol up to the server via
+        # a FakeTransport.
+        #
+        # Normally this would be done by the TCP socket code in Twisted, but we are
+        # stubbing that out here.
+        client_protocol = client_factory.buildProtocol(None)
+        client_protocol.makeConnection(
+            FakeTransport(server_tls_protocol, self.reactor, client_protocol)
+        )
+
+        # tell the server tls protocol to send its stuff back to the client, too
+        server_tls_protocol.makeConnection(
+            FakeTransport(client_protocol, self.reactor, server_tls_protocol)
+        )
+
+        # fish the test server back out of the server-side TLS protocol.
+        http_server = server_tls_protocol.wrappedProtocol
+
+        # give the reactor a pump to get the TLS juices flowing.
+        self.reactor.pump((0.1,))
+
+        self.assertEqual(len(http_server.requests), 1)
+        request = http_server.requests[0]
+
+        self.assertEqual(request.method, b"GET")
+        self.assertEqual(
+            request.path,
+            "/_matrix/media/r0/download/{}/{}".format(target, media_id).encode("utf-8"),
+        )
+        self.assertEqual(
+            request.requestHeaders.getRawHeaders(b"host"), [target.encode("utf-8")]
+        )
+
+        return channel, request
+
+    def test_basic(self):
+        """Test basic fetching of remote media from a single worker.
+        """
+        hs1 = self.make_worker_hs("synapse.app.generic_worker")
+
+        channel, request = self._get_media_req(hs1, "example.com:443", "ABC123")
+
+        request.setResponseCode(200)
+        request.responseHeaders.setRawHeaders(b"Content-Type", [b"text/plain"])
+        request.write(b"Hello!")
+        request.finish()
+
+        self.pump(0.1)
+
+        self.assertEqual(channel.code, 200)
+        self.assertEqual(channel.result["body"], b"Hello!")
+
+    def test_download_simple_file_race(self):
+        """Test that fetching remote media from two different processes at the
+        same time works.
+        """
+        hs1 = self.make_worker_hs("synapse.app.generic_worker")
+        hs2 = self.make_worker_hs("synapse.app.generic_worker")
+
+        start_count = self._count_remote_media()
+
+        # Make two requests without responding to the outbound media requests.
+        channel1, request1 = self._get_media_req(hs1, "example.com:443", "ABC123")
+        channel2, request2 = self._get_media_req(hs2, "example.com:443", "ABC123")
+
+        # Respond to the first outbound media request and check that the client
+        # request is successful
+        request1.setResponseCode(200)
+        request1.responseHeaders.setRawHeaders(b"Content-Type", [b"text/plain"])
+        request1.write(b"Hello!")
+        request1.finish()
+
+        self.pump(0.1)
+
+        self.assertEqual(channel1.code, 200, channel1.result["body"])
+        self.assertEqual(channel1.result["body"], b"Hello!")
+
+        # Now respond to the second with the same content.
+        request2.setResponseCode(200)
+        request2.responseHeaders.setRawHeaders(b"Content-Type", [b"text/plain"])
+        request2.write(b"Hello!")
+        request2.finish()
+
+        self.pump(0.1)
+
+        self.assertEqual(channel2.code, 200, channel2.result["body"])
+        self.assertEqual(channel2.result["body"], b"Hello!")
+
+        # We expect only one new file to have been persisted.
+        self.assertEqual(start_count + 1, self._count_remote_media())
+
+    def test_download_image_race(self):
+        """Test that fetching remote *images* from two different processes at
+        the same time works.
+
+        This checks that races generating thumbnails are handled correctly.
+        """
+        hs1 = self.make_worker_hs("synapse.app.generic_worker")
+        hs2 = self.make_worker_hs("synapse.app.generic_worker")
+
+        start_count = self._count_remote_thumbnails()
+
+        channel1, request1 = self._get_media_req(hs1, "example.com:443", "PIC1")
+        channel2, request2 = self._get_media_req(hs2, "example.com:443", "PIC1")
+
+        png_data = unhexlify(
+            b"89504e470d0a1a0a0000000d4948445200000001000000010806"
+            b"0000001f15c4890000000a49444154789c63000100000500010d"
+            b"0a2db40000000049454e44ae426082"
+        )
+
+        request1.setResponseCode(200)
+        request1.responseHeaders.setRawHeaders(b"Content-Type", [b"image/png"])
+        request1.write(png_data)
+        request1.finish()
+
+        self.pump(0.1)
+
+        self.assertEqual(channel1.code, 200, channel1.result["body"])
+        self.assertEqual(channel1.result["body"], png_data)
+
+        request2.setResponseCode(200)
+        request2.responseHeaders.setRawHeaders(b"Content-Type", [b"image/png"])
+        request2.write(png_data)
+        request2.finish()
+
+        self.pump(0.1)
+
+        self.assertEqual(channel2.code, 200, channel2.result["body"])
+        self.assertEqual(channel2.result["body"], png_data)
+
+        # We expect only three new thumbnails to have been persisted.
+        self.assertEqual(start_count + 3, self._count_remote_thumbnails())
+
+    def _count_remote_media(self) -> int:
+        """Count the number of files in our remote media directory.
+        """
+        path = os.path.join(
+            self.hs.get_media_repository().primary_base_path, "remote_content"
+        )
+        return sum(len(files) for _, _, files in os.walk(path))
+
+    def _count_remote_thumbnails(self) -> int:
+        """Count the number of files in our remote thumbnails directory.
+        """
+        path = os.path.join(
+            self.hs.get_media_repository().primary_base_path, "remote_thumbnail"
+        )
+        return sum(len(files) for _, _, files in os.walk(path))
+
+
+def get_connection_factory():
+    # this needs to happen once, but not until we are ready to run the first test
+    global test_server_connection_factory
+    if test_server_connection_factory is None:
+        test_server_connection_factory = TestServerTLSConnectionFactory(
+            sanlist=[b"DNS:example.com"]
+        )
+    return test_server_connection_factory
+
+
+def _build_test_server(connection_creator):
+    """Construct a test server
+
+    This builds an HTTP channel, wrapped with a TLSMemoryBIOProtocol
+
+    Args:
+        connection_creator (IOpenSSLServerConnectionCreator): thing to build
+            SSL connections
+        sanlist (list[bytes]): list of the SAN entries for the cert returned
+            by the server
+
+    Returns:
+        TLSMemoryBIOProtocol
+    """
+    server_factory = Factory.forProtocol(HTTPChannel)
+    # Request.finish expects the factory to have a 'log' method.
+    server_factory.log = _log_request
+
+    server_tls_factory = TLSMemoryBIOFactory(
+        connection_creator, isClient=False, wrappedFactory=server_factory
+    )
+
+    return server_tls_factory.buildProtocol(None)
+
+
+def _log_request(request):
+    """Implements Factory.log, which is expected by Request.finish"""
+    logger.info("Completed request %s", request)
diff --git a/tests/replication/test_pusher_shard.py b/tests/replication/test_pusher_shard.py
index 2bdc6edbb1..67c27a089f 100644
--- a/tests/replication/test_pusher_shard.py
+++ b/tests/replication/test_pusher_shard.py
@@ -55,7 +55,7 @@ class PusherShardTestCase(BaseMultiWorkerStreamTestCase):
         user_dict = self.get_success(
             self.hs.get_datastore().get_user_by_access_token(access_token)
         )
-        token_id = user_dict["token_id"]
+        token_id = user_dict.token_id
 
         self.get_success(
             self.hs.get_pusherpool().add_pusher(
diff --git a/tests/replication/test_sharded_event_persister.py b/tests/replication/test_sharded_event_persister.py
new file mode 100644
index 0000000000..77fc3856d5
--- /dev/null
+++ b/tests/replication/test_sharded_event_persister.py
@@ -0,0 +1,333 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+
+from mock import patch
+
+from synapse.api.room_versions import RoomVersion
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
+from synapse.rest.client.v2_alpha import sync
+
+from tests.replication._base import BaseMultiWorkerStreamTestCase
+from tests.server import make_request
+from tests.utils import USE_POSTGRES_FOR_TESTS
+
+logger = logging.getLogger(__name__)
+
+
+class EventPersisterShardTestCase(BaseMultiWorkerStreamTestCase):
+    """Checks event persisting sharding works
+    """
+
+    # Event persister sharding requires postgres (due to needing
+    # `MutliWriterIdGenerator`).
+    if not USE_POSTGRES_FOR_TESTS:
+        skip = "Requires Postgres"
+
+    servlets = [
+        admin.register_servlets_for_client_rest_resource,
+        room.register_servlets,
+        login.register_servlets,
+        sync.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        # Register a user who sends a message that we'll get notified about
+        self.other_user_id = self.register_user("otheruser", "pass")
+        self.other_access_token = self.login("otheruser", "pass")
+
+        self.room_creator = self.hs.get_room_creation_handler()
+        self.store = hs.get_datastore()
+
+    def default_config(self):
+        conf = super().default_config()
+        conf["redis"] = {"enabled": "true"}
+        conf["stream_writers"] = {"events": ["worker1", "worker2"]}
+        conf["instance_map"] = {
+            "worker1": {"host": "testserv", "port": 1001},
+            "worker2": {"host": "testserv", "port": 1002},
+        }
+        return conf
+
+    def _create_room(self, room_id: str, user_id: str, tok: str):
+        """Create a room with given room_id
+        """
+
+        # We control the room ID generation by patching out the
+        # `_generate_room_id` method
+        async def generate_room(
+            creator_id: str, is_public: bool, room_version: RoomVersion
+        ):
+            await self.store.store_room(
+                room_id=room_id,
+                room_creator_user_id=creator_id,
+                is_public=is_public,
+                room_version=room_version,
+            )
+            return room_id
+
+        with patch(
+            "synapse.handlers.room.RoomCreationHandler._generate_room_id"
+        ) as mock:
+            mock.side_effect = generate_room
+            self.helper.create_room_as(user_id, tok=tok)
+
+    def test_basic(self):
+        """Simple test to ensure that multiple rooms can be created and joined,
+        and that different rooms get handled by different instances.
+        """
+
+        self.make_worker_hs(
+            "synapse.app.generic_worker", {"worker_name": "worker1"},
+        )
+
+        self.make_worker_hs(
+            "synapse.app.generic_worker", {"worker_name": "worker2"},
+        )
+
+        persisted_on_1 = False
+        persisted_on_2 = False
+
+        store = self.hs.get_datastore()
+
+        user_id = self.register_user("user", "pass")
+        access_token = self.login("user", "pass")
+
+        # Keep making new rooms until we see rooms being persisted on both
+        # workers.
+        for _ in range(10):
+            # Create a room
+            room = self.helper.create_room_as(user_id, tok=access_token)
+
+            # The other user joins
+            self.helper.join(
+                room=room, user=self.other_user_id, tok=self.other_access_token
+            )
+
+            # The other user sends some messages
+            rseponse = self.helper.send(room, body="Hi!", tok=self.other_access_token)
+            event_id = rseponse["event_id"]
+
+            # The event position includes which instance persisted the event.
+            pos = self.get_success(store.get_position_for_event(event_id))
+
+            persisted_on_1 |= pos.instance_name == "worker1"
+            persisted_on_2 |= pos.instance_name == "worker2"
+
+            if persisted_on_1 and persisted_on_2:
+                break
+
+        self.assertTrue(persisted_on_1)
+        self.assertTrue(persisted_on_2)
+
+    def test_vector_clock_token(self):
+        """Tests that using a stream token with a vector clock component works
+        correctly with basic /sync and /messages usage.
+        """
+
+        self.make_worker_hs(
+            "synapse.app.generic_worker", {"worker_name": "worker1"},
+        )
+
+        worker_hs2 = self.make_worker_hs(
+            "synapse.app.generic_worker", {"worker_name": "worker2"},
+        )
+
+        sync_hs = self.make_worker_hs(
+            "synapse.app.generic_worker", {"worker_name": "sync"},
+        )
+        sync_hs_site = self._hs_to_site[sync_hs]
+
+        # Specially selected room IDs that get persisted on different workers.
+        room_id1 = "!foo:test"
+        room_id2 = "!baz:test"
+
+        self.assertEqual(
+            self.hs.config.worker.events_shard_config.get_instance(room_id1), "worker1"
+        )
+        self.assertEqual(
+            self.hs.config.worker.events_shard_config.get_instance(room_id2), "worker2"
+        )
+
+        user_id = self.register_user("user", "pass")
+        access_token = self.login("user", "pass")
+
+        store = self.hs.get_datastore()
+
+        # Create two room on the different workers.
+        self._create_room(room_id1, user_id, access_token)
+        self._create_room(room_id2, user_id, access_token)
+
+        # The other user joins
+        self.helper.join(
+            room=room_id1, user=self.other_user_id, tok=self.other_access_token
+        )
+        self.helper.join(
+            room=room_id2, user=self.other_user_id, tok=self.other_access_token
+        )
+
+        # Do an initial sync so that we're up to date.
+        request, channel = make_request(
+            self.reactor, sync_hs_site, "GET", "/sync", access_token=access_token
+        )
+        next_batch = channel.json_body["next_batch"]
+
+        # We now gut wrench into the events stream MultiWriterIdGenerator on
+        # worker2 to mimic it getting stuck persisting an event. This ensures
+        # that when we send an event on worker1 we end up in a state where
+        # worker2 events stream position lags that on worker1, resulting in a
+        # RoomStreamToken with a non-empty instance map component.
+        #
+        # Worker2's event stream position will not advance until we call
+        # __aexit__ again.
+        actx = worker_hs2.get_datastore()._stream_id_gen.get_next()
+        self.get_success(actx.__aenter__())
+
+        response = self.helper.send(room_id1, body="Hi!", tok=self.other_access_token)
+        first_event_in_room1 = response["event_id"]
+
+        # Assert that the current stream token has an instance map component, as
+        # we are trying to test vector clock tokens.
+        room_stream_token = store.get_room_max_token()
+        self.assertNotEqual(len(room_stream_token.instance_map), 0)
+
+        # Check that syncing still gets the new event, despite the gap in the
+        # stream IDs.
+        request, channel = make_request(
+            self.reactor,
+            sync_hs_site,
+            "GET",
+            "/sync?since={}".format(next_batch),
+            access_token=access_token,
+        )
+
+        # We should only see the new event and nothing else
+        self.assertIn(room_id1, channel.json_body["rooms"]["join"])
+        self.assertNotIn(room_id2, channel.json_body["rooms"]["join"])
+
+        events = channel.json_body["rooms"]["join"][room_id1]["timeline"]["events"]
+        self.assertListEqual(
+            [first_event_in_room1], [event["event_id"] for event in events]
+        )
+
+        # Get the next batch and makes sure its a vector clock style token.
+        vector_clock_token = channel.json_body["next_batch"]
+        self.assertTrue(vector_clock_token.startswith("m"))
+
+        # Now that we've got a vector clock token we finish the fake persisting
+        # an event we started above.
+        self.get_success(actx.__aexit__(None, None, None))
+
+        # Now try and send an event to the other rooom so that we can test that
+        # the vector clock style token works as a `since` token.
+        response = self.helper.send(room_id2, body="Hi!", tok=self.other_access_token)
+        first_event_in_room2 = response["event_id"]
+
+        request, channel = make_request(
+            self.reactor,
+            sync_hs_site,
+            "GET",
+            "/sync?since={}".format(vector_clock_token),
+            access_token=access_token,
+        )
+
+        self.assertNotIn(room_id1, channel.json_body["rooms"]["join"])
+        self.assertIn(room_id2, channel.json_body["rooms"]["join"])
+
+        events = channel.json_body["rooms"]["join"][room_id2]["timeline"]["events"]
+        self.assertListEqual(
+            [first_event_in_room2], [event["event_id"] for event in events]
+        )
+
+        next_batch = channel.json_body["next_batch"]
+
+        # We also want to test that the vector clock style token works with
+        # pagination. We do this by sending a couple of new events into the room
+        # and syncing again to get a prev_batch token for each room, then
+        # paginating from there back to the vector clock token.
+        self.helper.send(room_id1, body="Hi again!", tok=self.other_access_token)
+        self.helper.send(room_id2, body="Hi again!", tok=self.other_access_token)
+
+        request, channel = make_request(
+            self.reactor,
+            sync_hs_site,
+            "GET",
+            "/sync?since={}".format(next_batch),
+            access_token=access_token,
+        )
+
+        prev_batch1 = channel.json_body["rooms"]["join"][room_id1]["timeline"][
+            "prev_batch"
+        ]
+        prev_batch2 = channel.json_body["rooms"]["join"][room_id2]["timeline"][
+            "prev_batch"
+        ]
+
+        # Paginating back in the first room should not produce any results, as
+        # no events have happened in it. This tests that we are correctly
+        # filtering results based on the vector clock portion.
+        request, channel = make_request(
+            self.reactor,
+            sync_hs_site,
+            "GET",
+            "/rooms/{}/messages?from={}&to={}&dir=b".format(
+                room_id1, prev_batch1, vector_clock_token
+            ),
+            access_token=access_token,
+        )
+        self.assertListEqual([], channel.json_body["chunk"])
+
+        # Paginating back on the second room should produce the first event
+        # again. This tests that pagination isn't completely broken.
+        request, channel = make_request(
+            self.reactor,
+            sync_hs_site,
+            "GET",
+            "/rooms/{}/messages?from={}&to={}&dir=b".format(
+                room_id2, prev_batch2, vector_clock_token
+            ),
+            access_token=access_token,
+        )
+        self.assertEqual(len(channel.json_body["chunk"]), 1)
+        self.assertEqual(
+            channel.json_body["chunk"][0]["event_id"], first_event_in_room2
+        )
+
+        # Paginating forwards should give the same results
+        request, channel = make_request(
+            self.reactor,
+            sync_hs_site,
+            "GET",
+            "/rooms/{}/messages?from={}&to={}&dir=f".format(
+                room_id1, vector_clock_token, prev_batch1
+            ),
+            access_token=access_token,
+        )
+        self.assertListEqual([], channel.json_body["chunk"])
+
+        request, channel = make_request(
+            self.reactor,
+            sync_hs_site,
+            "GET",
+            "/rooms/{}/messages?from={}&to={}&dir=f".format(
+                room_id2, vector_clock_token, prev_batch2,
+            ),
+            access_token=access_token,
+        )
+        self.assertEqual(len(channel.json_body["chunk"]), 1)
+        self.assertEqual(
+            channel.json_body["chunk"][0]["event_id"], first_event_in_room2
+        )
diff --git a/tests/rest/admin/test_admin.py b/tests/rest/admin/test_admin.py
index 0f1144fe1e..4f76f8f768 100644
--- a/tests/rest/admin/test_admin.py
+++ b/tests/rest/admin/test_admin.py
@@ -30,19 +30,19 @@ from synapse.rest.client.v1 import login, room
 from synapse.rest.client.v2_alpha import groups
 
 from tests import unittest
+from tests.server import FakeSite, make_request
 
 
 class VersionTestCase(unittest.HomeserverTestCase):
     url = "/_synapse/admin/v1/server_version"
 
-    def create_test_json_resource(self):
+    def create_test_resource(self):
         resource = JsonResource(self.hs)
         VersionServlet(self.hs).register(resource)
         return resource
 
     def test_version_string(self):
         request, channel = self.make_request("GET", self.url, shorthand=False)
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(
@@ -75,7 +75,6 @@ class DeleteGroupTestCase(unittest.HomeserverTestCase):
             content={"localpart": "test"},
         )
 
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         group_id = channel.json_body["group_id"]
@@ -88,14 +87,12 @@ class DeleteGroupTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", url.encode("ascii"), access_token=self.admin_user_tok, content={}
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         url = "/groups/%s/self/accept_invite" % (group_id,)
         request, channel = self.make_request(
             "PUT", url.encode("ascii"), access_token=self.other_user_token, content={}
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Check other user knows they're in the group
@@ -103,7 +100,7 @@ class DeleteGroupTestCase(unittest.HomeserverTestCase):
         self.assertIn(group_id, self._get_groups_user_is_in(self.other_user_token))
 
         # Now delete the group
-        url = "/admin/delete_group/" + group_id
+        url = "/_synapse/admin/v1/delete_group/" + group_id
         request, channel = self.make_request(
             "POST",
             url.encode("ascii"),
@@ -111,7 +108,6 @@ class DeleteGroupTestCase(unittest.HomeserverTestCase):
             content={"localpart": "test"},
         )
 
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Check group returns 404
@@ -131,7 +127,6 @@ class DeleteGroupTestCase(unittest.HomeserverTestCase):
             "GET", url.encode("ascii"), access_token=self.admin_user_tok
         )
 
-        self.render(request)
         self.assertEqual(
             expect_code, int(channel.result["code"]), msg=channel.result["body"]
         )
@@ -143,7 +138,6 @@ class DeleteGroupTestCase(unittest.HomeserverTestCase):
             "GET", "/joined_groups".encode("ascii"), access_token=access_token
         )
 
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         return channel.json_body["groups"]
@@ -222,11 +216,14 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
 
     def _ensure_quarantined(self, admin_user_tok, server_and_media_id):
         """Ensure a piece of media is quarantined when trying to access it."""
-        request, channel = self.make_request(
-            "GET", server_and_media_id, shorthand=False, access_token=admin_user_tok,
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(self.download_resource),
+            "GET",
+            server_and_media_id,
+            shorthand=False,
+            access_token=admin_user_tok,
         )
-        request.render(self.download_resource)
-        self.pump(1.0)
 
         # Should be quarantined
         self.assertEqual(
@@ -247,7 +244,6 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url.encode("ascii"), access_token=non_admin_user_tok,
         )
-        self.render(request)
 
         # Expect a forbidden error
         self.assertEqual(
@@ -261,7 +257,6 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url.encode("ascii"), access_token=non_admin_user_tok,
         )
-        self.render(request)
 
         # Expect a forbidden error
         self.assertEqual(
@@ -287,14 +282,14 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
         server_name, media_id = server_name_and_media_id.split("/")
 
         # Attempt to access the media
-        request, channel = self.make_request(
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(self.download_resource),
             "GET",
             server_name_and_media_id,
             shorthand=False,
             access_token=non_admin_user_tok,
         )
-        request.render(self.download_resource)
-        self.pump(1.0)
 
         # Should be successful
         self.assertEqual(200, int(channel.code), msg=channel.result["body"])
@@ -305,7 +300,6 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
             urllib.parse.quote(media_id),
         )
         request, channel = self.make_request("POST", url, access_token=admin_user_tok,)
-        self.render(request)
         self.pump(1.0)
         self.assertEqual(200, int(channel.code), msg=channel.result["body"])
 
@@ -358,7 +352,6 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
                 room_id
             )
         request, channel = self.make_request("POST", url, access_token=admin_user_tok,)
-        self.render(request)
         self.pump(1.0)
         self.assertEqual(200, int(channel.code), msg=channel.result["body"])
         self.assertEqual(
@@ -405,7 +398,6 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url.encode("ascii"), access_token=admin_user_tok,
         )
-        self.render(request)
         self.pump(1.0)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(
@@ -448,7 +440,6 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url.encode("ascii"), access_token=admin_user_tok,
         )
-        self.render(request)
         self.pump(1.0)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(
@@ -462,14 +453,14 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
         self._ensure_quarantined(admin_user_tok, server_and_media_id_1)
 
         # Attempt to access each piece of media
-        request, channel = self.make_request(
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(self.download_resource),
             "GET",
             server_and_media_id_2,
             shorthand=False,
             access_token=non_admin_user_tok,
         )
-        request.render(self.download_resource)
-        self.pump(1.0)
 
         # Shouldn't be quarantined
         self.assertEqual(
diff --git a/tests/rest/admin/test_device.py b/tests/rest/admin/test_device.py
index 92c9058887..cf3a007598 100644
--- a/tests/rest/admin/test_device.py
+++ b/tests/rest/admin/test_device.py
@@ -51,19 +51,16 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         Try to get a device of an user without authentication.
         """
         request, channel = self.make_request("GET", self.url, b"{}")
-        self.render(request)
 
         self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
         request, channel = self.make_request("PUT", self.url, b"{}")
-        self.render(request)
 
         self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
         request, channel = self.make_request("DELETE", self.url, b"{}")
-        self.render(request)
 
         self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
@@ -75,7 +72,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=self.other_user_token,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -83,7 +79,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", self.url, access_token=self.other_user_token,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -91,7 +86,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "DELETE", self.url, access_token=self.other_user_token,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -108,7 +102,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
@@ -116,7 +109,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
@@ -124,7 +116,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "DELETE", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
@@ -141,7 +132,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only lookup local users", channel.json_body["error"])
@@ -149,7 +139,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only lookup local users", channel.json_body["error"])
@@ -157,7 +146,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "DELETE", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only lookup local users", channel.json_body["error"])
@@ -173,7 +161,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
@@ -181,14 +168,12 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
 
         request, channel = self.make_request(
             "DELETE", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         # Delete unknown device returns status 200
         self.assertEqual(200, channel.code, msg=channel.json_body)
@@ -218,7 +203,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.TOO_LARGE, channel.json_body["errcode"])
@@ -227,7 +211,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
         self.assertEqual("new display", channel.json_body["display_name"])
@@ -247,7 +230,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", self.url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
 
@@ -255,7 +237,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
         self.assertEqual("new display", channel.json_body["display_name"])
@@ -272,7 +253,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
 
@@ -280,7 +260,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
         self.assertEqual("new displayname", channel.json_body["display_name"])
@@ -292,7 +271,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
         self.assertEqual(self.other_user, channel.json_body["user_id"])
@@ -316,7 +294,6 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "DELETE", self.url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
 
@@ -347,7 +324,6 @@ class DevicesRestTestCase(unittest.HomeserverTestCase):
         Try to list devices of an user without authentication.
         """
         request, channel = self.make_request("GET", self.url, b"{}")
-        self.render(request)
 
         self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
@@ -361,7 +337,6 @@ class DevicesRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=other_user_token,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -374,7 +349,6 @@ class DevicesRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
@@ -388,11 +362,25 @@ class DevicesRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only lookup local users", channel.json_body["error"])
 
+    def test_user_has_no_devices(self):
+        """
+        Tests that a normal lookup for devices is successfully
+        if user has no devices
+        """
+
+        # Get devices
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(0, channel.json_body["total"])
+        self.assertEqual(0, len(channel.json_body["devices"]))
+
     def test_get_devices(self):
         """
         Tests that a normal lookup for devices is successfully
@@ -406,9 +394,9 @@ class DevicesRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(number_devices, channel.json_body["total"])
         self.assertEqual(number_devices, len(channel.json_body["devices"]))
         self.assertEqual(self.other_user, channel.json_body["devices"][0]["user_id"])
         # Check that all fields are available
@@ -444,7 +432,6 @@ class DeleteDevicesRestTestCase(unittest.HomeserverTestCase):
         Try to delete devices of an user without authentication.
         """
         request, channel = self.make_request("POST", self.url, b"{}")
-        self.render(request)
 
         self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
@@ -458,7 +445,6 @@ class DeleteDevicesRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", self.url, access_token=other_user_token,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -471,7 +457,6 @@ class DeleteDevicesRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
@@ -485,7 +470,6 @@ class DeleteDevicesRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only lookup local users", channel.json_body["error"])
@@ -501,7 +485,6 @@ class DeleteDevicesRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         # Delete unknown devices returns status 200
         self.assertEqual(200, channel.code, msg=channel.json_body)
@@ -533,7 +516,6 @@ class DeleteDevicesRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
 
diff --git a/tests/rest/admin/test_event_reports.py b/tests/rest/admin/test_event_reports.py
index bf79086f78..11b72c10f7 100644
--- a/tests/rest/admin/test_event_reports.py
+++ b/tests/rest/admin/test_event_reports.py
@@ -70,6 +70,15 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
 
         self.url = "/_synapse/admin/v1/event_reports"
 
+    def test_no_auth(self):
+        """
+        Try to get an event report without authentication.
+        """
+        request, channel = self.make_request("GET", self.url, b"{}")
+
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
     def test_requester_is_no_admin(self):
         """
         If the user is not a server admin, an error 403 is returned.
@@ -78,7 +87,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=self.other_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -91,7 +99,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -107,7 +114,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?limit=5", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -123,7 +129,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?from=5", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -139,7 +144,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?from=5&limit=10", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -157,7 +161,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
             self.url + "?room_id=%s" % self.room_id1,
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 10)
@@ -178,7 +181,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
             self.url + "?user_id=%s" % self.other_user,
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 10)
@@ -199,7 +201,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
             self.url + "?user_id=%s&room_id=%s" % (self.other_user, self.room_id1),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 5)
@@ -220,7 +221,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?dir=b", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -237,7 +237,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?dir=f", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -258,7 +257,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?dir=bar", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
@@ -266,13 +264,12 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
 
     def test_limit_is_negative(self):
         """
-        Testing that a negative list parameter returns a 400
+        Testing that a negative limit parameter returns a 400
         """
 
         request, channel = self.make_request(
             "GET", self.url + "?limit=-5", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
@@ -285,7 +282,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?from=-5", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
@@ -300,7 +296,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?limit=20", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -312,7 +307,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?limit=21", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -324,7 +318,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?limit=19", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -337,7 +330,6 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url + "?from=19", access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(channel.json_body["total"], 20)
@@ -356,11 +348,10 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
             json.dumps({"score": -100, "reason": "this makes me sad"}),
             access_token=user_tok,
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
     def _check_fields(self, content):
-        """Checks that all attributes are present in a event report
+        """Checks that all attributes are present in an event report
         """
         for c in content:
             self.assertIn("id", c)
@@ -368,15 +359,167 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
             self.assertIn("room_id", c)
             self.assertIn("event_id", c)
             self.assertIn("user_id", c)
-            self.assertIn("reason", c)
-            self.assertIn("content", c)
             self.assertIn("sender", c)
-            self.assertIn("room_alias", c)
-            self.assertIn("event_json", c)
-            self.assertIn("score", c["content"])
-            self.assertIn("reason", c["content"])
-            self.assertIn("auth_events", c["event_json"])
-            self.assertIn("type", c["event_json"])
-            self.assertIn("room_id", c["event_json"])
-            self.assertIn("sender", c["event_json"])
-            self.assertIn("content", c["event_json"])
+            self.assertIn("canonical_alias", c)
+            self.assertIn("name", c)
+            self.assertIn("score", c)
+            self.assertIn("reason", c)
+
+
+class EventReportDetailTestCase(unittest.HomeserverTestCase):
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+        report_event.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.store = hs.get_datastore()
+
+        self.admin_user = self.register_user("admin", "pass", admin=True)
+        self.admin_user_tok = self.login("admin", "pass")
+
+        self.other_user = self.register_user("user", "pass")
+        self.other_user_tok = self.login("user", "pass")
+
+        self.room_id1 = self.helper.create_room_as(
+            self.other_user, tok=self.other_user_tok, is_public=True
+        )
+        self.helper.join(self.room_id1, user=self.admin_user, tok=self.admin_user_tok)
+
+        self._create_event_and_report(
+            room_id=self.room_id1, user_tok=self.other_user_tok,
+        )
+
+        # first created event report gets `id`=2
+        self.url = "/_synapse/admin/v1/event_reports/2"
+
+    def test_no_auth(self):
+        """
+        Try to get event report without authentication.
+        """
+        request, channel = self.make_request("GET", self.url, b"{}")
+
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
+    def test_requester_is_no_admin(self):
+        """
+        If the user is not a server admin, an error 403 is returned.
+        """
+
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.other_user_tok,
+        )
+
+        self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
+
+    def test_default_success(self):
+        """
+        Testing get a reported event
+        """
+
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self._check_fields(channel.json_body)
+
+    def test_invalid_report_id(self):
+        """
+        Testing that an invalid `report_id` returns a 400.
+        """
+
+        # `report_id` is negative
+        request, channel = self.make_request(
+            "GET",
+            "/_synapse/admin/v1/event_reports/-123",
+            access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+        self.assertEqual(
+            "The report_id parameter must be a string representing a positive integer.",
+            channel.json_body["error"],
+        )
+
+        # `report_id` is a non-numerical string
+        request, channel = self.make_request(
+            "GET",
+            "/_synapse/admin/v1/event_reports/abcdef",
+            access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+        self.assertEqual(
+            "The report_id parameter must be a string representing a positive integer.",
+            channel.json_body["error"],
+        )
+
+        # `report_id` is undefined
+        request, channel = self.make_request(
+            "GET",
+            "/_synapse/admin/v1/event_reports/",
+            access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+        self.assertEqual(
+            "The report_id parameter must be a string representing a positive integer.",
+            channel.json_body["error"],
+        )
+
+    def test_report_id_not_found(self):
+        """
+        Testing that a not existing `report_id` returns a 404.
+        """
+
+        request, channel = self.make_request(
+            "GET",
+            "/_synapse/admin/v1/event_reports/123",
+            access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(404, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
+        self.assertEqual("Event report not found", channel.json_body["error"])
+
+    def _create_event_and_report(self, room_id, user_tok):
+        """Create and report events
+        """
+        resp = self.helper.send(room_id, tok=user_tok)
+        event_id = resp["event_id"]
+
+        request, channel = self.make_request(
+            "POST",
+            "rooms/%s/report/%s" % (room_id, event_id),
+            json.dumps({"score": -100, "reason": "this makes me sad"}),
+            access_token=user_tok,
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+    def _check_fields(self, content):
+        """Checks that all attributes are present in a event report
+        """
+        self.assertIn("id", content)
+        self.assertIn("received_ts", content)
+        self.assertIn("room_id", content)
+        self.assertIn("event_id", content)
+        self.assertIn("user_id", content)
+        self.assertIn("sender", content)
+        self.assertIn("canonical_alias", content)
+        self.assertIn("name", content)
+        self.assertIn("event_json", content)
+        self.assertIn("score", content)
+        self.assertIn("reason", content)
+        self.assertIn("auth_events", content["event_json"])
+        self.assertIn("type", content["event_json"])
+        self.assertIn("room_id", content["event_json"])
+        self.assertIn("sender", content["event_json"])
+        self.assertIn("content", content["event_json"])
diff --git a/tests/rest/admin/test_media.py b/tests/rest/admin/test_media.py
new file mode 100644
index 0000000000..dadf9db660
--- /dev/null
+++ b/tests/rest/admin/test_media.py
@@ -0,0 +1,545 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 Dirk Klimpel
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import json
+import os
+from binascii import unhexlify
+
+import synapse.rest.admin
+from synapse.api.errors import Codes
+from synapse.rest.client.v1 import login, profile, room
+from synapse.rest.media.v1.filepath import MediaFilePaths
+
+from tests import unittest
+from tests.server import FakeSite, make_request
+
+
+class DeleteMediaByIDTestCase(unittest.HomeserverTestCase):
+
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        synapse.rest.admin.register_servlets_for_media_repo,
+        login.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.handler = hs.get_device_handler()
+        self.media_repo = hs.get_media_repository_resource()
+        self.server_name = hs.hostname
+
+        self.admin_user = self.register_user("admin", "pass", admin=True)
+        self.admin_user_tok = self.login("admin", "pass")
+
+        self.filepaths = MediaFilePaths(hs.config.media_store_path)
+
+    def test_no_auth(self):
+        """
+        Try to delete media without authentication.
+        """
+        url = "/_synapse/admin/v1/media/%s/%s" % (self.server_name, "12345")
+
+        request, channel = self.make_request("DELETE", url, b"{}")
+
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
+    def test_requester_is_no_admin(self):
+        """
+        If the user is not a server admin, an error is returned.
+        """
+        self.other_user = self.register_user("user", "pass")
+        self.other_user_token = self.login("user", "pass")
+
+        url = "/_synapse/admin/v1/media/%s/%s" % (self.server_name, "12345")
+
+        request, channel = self.make_request(
+            "DELETE", url, access_token=self.other_user_token,
+        )
+
+        self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
+
+    def test_media_does_not_exist(self):
+        """
+        Tests that a lookup for a media that does not exist returns a 404
+        """
+        url = "/_synapse/admin/v1/media/%s/%s" % (self.server_name, "12345")
+
+        request, channel = self.make_request(
+            "DELETE", url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(404, channel.code, msg=channel.json_body)
+        self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
+
+    def test_media_is_not_local(self):
+        """
+        Tests that a lookup for a media that is not a local returns a 400
+        """
+        url = "/_synapse/admin/v1/media/%s/%s" % ("unknown_domain", "12345")
+
+        request, channel = self.make_request(
+            "DELETE", url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, channel.code, msg=channel.json_body)
+        self.assertEqual("Can only delete local media", channel.json_body["error"])
+
+    def test_delete_media(self):
+        """
+        Tests that delete a media is successfully
+        """
+
+        download_resource = self.media_repo.children[b"download"]
+        upload_resource = self.media_repo.children[b"upload"]
+        image_data = unhexlify(
+            b"89504e470d0a1a0a0000000d4948445200000001000000010806"
+            b"0000001f15c4890000000a49444154789c63000100000500010d"
+            b"0a2db40000000049454e44ae426082"
+        )
+
+        # Upload some media into the room
+        response = self.helper.upload_media(
+            upload_resource, image_data, tok=self.admin_user_tok, expect_code=200
+        )
+        # Extract media ID from the response
+        server_and_media_id = response["content_uri"][6:]  # Cut off 'mxc://'
+        server_name, media_id = server_and_media_id.split("/")
+
+        self.assertEqual(server_name, self.server_name)
+
+        # Attempt to access media
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(download_resource),
+            "GET",
+            server_and_media_id,
+            shorthand=False,
+            access_token=self.admin_user_tok,
+        )
+
+        # Should be successful
+        self.assertEqual(
+            200,
+            channel.code,
+            msg=(
+                "Expected to receive a 200 on accessing media: %s" % server_and_media_id
+            ),
+        )
+
+        # Test if the file exists
+        local_path = self.filepaths.local_media_filepath(media_id)
+        self.assertTrue(os.path.exists(local_path))
+
+        url = "/_synapse/admin/v1/media/%s/%s" % (self.server_name, media_id)
+
+        # Delete media
+        request, channel = self.make_request(
+            "DELETE", url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(1, channel.json_body["total"])
+        self.assertEqual(
+            media_id, channel.json_body["deleted_media"][0],
+        )
+
+        # Attempt to access media
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(download_resource),
+            "GET",
+            server_and_media_id,
+            shorthand=False,
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(
+            404,
+            channel.code,
+            msg=(
+                "Expected to receive a 404 on accessing deleted media: %s"
+                % server_and_media_id
+            ),
+        )
+
+        # Test if the file is deleted
+        self.assertFalse(os.path.exists(local_path))
+
+
+class DeleteMediaByDateSizeTestCase(unittest.HomeserverTestCase):
+
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        synapse.rest.admin.register_servlets_for_media_repo,
+        login.register_servlets,
+        profile.register_servlets,
+        room.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.handler = hs.get_device_handler()
+        self.media_repo = hs.get_media_repository_resource()
+        self.server_name = hs.hostname
+
+        self.admin_user = self.register_user("admin", "pass", admin=True)
+        self.admin_user_tok = self.login("admin", "pass")
+
+        self.filepaths = MediaFilePaths(hs.config.media_store_path)
+        self.url = "/_synapse/admin/v1/media/%s/delete" % self.server_name
+
+    def test_no_auth(self):
+        """
+        Try to delete media without authentication.
+        """
+
+        request, channel = self.make_request("POST", self.url, b"{}")
+
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
+    def test_requester_is_no_admin(self):
+        """
+        If the user is not a server admin, an error is returned.
+        """
+        self.other_user = self.register_user("user", "pass")
+        self.other_user_token = self.login("user", "pass")
+
+        request, channel = self.make_request(
+            "POST", self.url, access_token=self.other_user_token,
+        )
+
+        self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
+
+    def test_media_is_not_local(self):
+        """
+        Tests that a lookup for media that is not local returns a 400
+        """
+        url = "/_synapse/admin/v1/media/%s/delete" % "unknown_domain"
+
+        request, channel = self.make_request(
+            "POST", url + "?before_ts=1234", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, channel.code, msg=channel.json_body)
+        self.assertEqual("Can only delete local media", channel.json_body["error"])
+
+    def test_missing_parameter(self):
+        """
+        If the parameter `before_ts` is missing, an error is returned.
+        """
+        request, channel = self.make_request(
+            "POST", self.url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
+        self.assertEqual(
+            "Missing integer query parameter b'before_ts'", channel.json_body["error"]
+        )
+
+    def test_invalid_parameter(self):
+        """
+        If parameters are invalid, an error is returned.
+        """
+        request, channel = self.make_request(
+            "POST", self.url + "?before_ts=-1234", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+        self.assertEqual(
+            "Query parameter before_ts must be a string representing a positive integer.",
+            channel.json_body["error"],
+        )
+
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=1234&size_gt=-1234",
+            access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+        self.assertEqual(
+            "Query parameter size_gt must be a string representing a positive integer.",
+            channel.json_body["error"],
+        )
+
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=1234&keep_profiles=not_bool",
+            access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.UNKNOWN, channel.json_body["errcode"])
+        self.assertEqual(
+            "Boolean query parameter b'keep_profiles' must be one of ['true', 'false']",
+            channel.json_body["error"],
+        )
+
+    def test_delete_media_never_accessed(self):
+        """
+        Tests that media deleted if it is older than `before_ts` and never accessed
+        `last_access_ts` is `NULL` and `created_ts` < `before_ts`
+        """
+
+        # upload and do not access
+        server_and_media_id = self._create_media()
+        self.pump(1.0)
+
+        # test that the file exists
+        media_id = server_and_media_id.split("/")[1]
+        local_path = self.filepaths.local_media_filepath(media_id)
+        self.assertTrue(os.path.exists(local_path))
+
+        # timestamp after upload/create
+        now_ms = self.clock.time_msec()
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=" + str(now_ms),
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(1, channel.json_body["total"])
+        self.assertEqual(
+            media_id, channel.json_body["deleted_media"][0],
+        )
+
+        self._access_media(server_and_media_id, False)
+
+    def test_keep_media_by_date(self):
+        """
+        Tests that media is not deleted if it is newer than `before_ts`
+        """
+
+        # timestamp before upload
+        now_ms = self.clock.time_msec()
+        server_and_media_id = self._create_media()
+
+        self._access_media(server_and_media_id)
+
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=" + str(now_ms),
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(0, channel.json_body["total"])
+
+        self._access_media(server_and_media_id)
+
+        # timestamp after upload
+        now_ms = self.clock.time_msec()
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=" + str(now_ms),
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(1, channel.json_body["total"])
+        self.assertEqual(
+            server_and_media_id.split("/")[1], channel.json_body["deleted_media"][0],
+        )
+
+        self._access_media(server_and_media_id, False)
+
+    def test_keep_media_by_size(self):
+        """
+        Tests that media is not deleted if its size is smaller than or equal
+        to `size_gt`
+        """
+        server_and_media_id = self._create_media()
+
+        self._access_media(server_and_media_id)
+
+        now_ms = self.clock.time_msec()
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=" + str(now_ms) + "&size_gt=67",
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(0, channel.json_body["total"])
+
+        self._access_media(server_and_media_id)
+
+        now_ms = self.clock.time_msec()
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=" + str(now_ms) + "&size_gt=66",
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(1, channel.json_body["total"])
+        self.assertEqual(
+            server_and_media_id.split("/")[1], channel.json_body["deleted_media"][0],
+        )
+
+        self._access_media(server_and_media_id, False)
+
+    def test_keep_media_by_user_avatar(self):
+        """
+        Tests that we do not delete media if is used as a user avatar
+        Tests parameter `keep_profiles`
+        """
+        server_and_media_id = self._create_media()
+
+        self._access_media(server_and_media_id)
+
+        # set media as avatar
+        request, channel = self.make_request(
+            "PUT",
+            "/profile/%s/avatar_url" % (self.admin_user,),
+            content=json.dumps({"avatar_url": "mxc://%s" % (server_and_media_id,)}),
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+
+        now_ms = self.clock.time_msec()
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=" + str(now_ms) + "&keep_profiles=true",
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(0, channel.json_body["total"])
+
+        self._access_media(server_and_media_id)
+
+        now_ms = self.clock.time_msec()
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=" + str(now_ms) + "&keep_profiles=false",
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(1, channel.json_body["total"])
+        self.assertEqual(
+            server_and_media_id.split("/")[1], channel.json_body["deleted_media"][0],
+        )
+
+        self._access_media(server_and_media_id, False)
+
+    def test_keep_media_by_room_avatar(self):
+        """
+        Tests that we do not delete media if it is used as a room avatar
+        Tests parameter `keep_profiles`
+        """
+        server_and_media_id = self._create_media()
+
+        self._access_media(server_and_media_id)
+
+        # set media as room avatar
+        room_id = self.helper.create_room_as(self.admin_user, tok=self.admin_user_tok)
+        request, channel = self.make_request(
+            "PUT",
+            "/rooms/%s/state/m.room.avatar" % (room_id,),
+            content=json.dumps({"url": "mxc://%s" % (server_and_media_id,)}),
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+
+        now_ms = self.clock.time_msec()
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=" + str(now_ms) + "&keep_profiles=true",
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(0, channel.json_body["total"])
+
+        self._access_media(server_and_media_id)
+
+        now_ms = self.clock.time_msec()
+        request, channel = self.make_request(
+            "POST",
+            self.url + "?before_ts=" + str(now_ms) + "&keep_profiles=false",
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(1, channel.json_body["total"])
+        self.assertEqual(
+            server_and_media_id.split("/")[1], channel.json_body["deleted_media"][0],
+        )
+
+        self._access_media(server_and_media_id, False)
+
+    def _create_media(self):
+        """
+        Create a media and return media_id and server_and_media_id
+        """
+        upload_resource = self.media_repo.children[b"upload"]
+        # file size is 67 Byte
+        image_data = unhexlify(
+            b"89504e470d0a1a0a0000000d4948445200000001000000010806"
+            b"0000001f15c4890000000a49444154789c63000100000500010d"
+            b"0a2db40000000049454e44ae426082"
+        )
+
+        # Upload some media into the room
+        response = self.helper.upload_media(
+            upload_resource, image_data, tok=self.admin_user_tok, expect_code=200
+        )
+        # Extract media ID from the response
+        server_and_media_id = response["content_uri"][6:]  # Cut off 'mxc://'
+        server_name = server_and_media_id.split("/")[0]
+
+        # Check that new media is a local and not remote
+        self.assertEqual(server_name, self.server_name)
+
+        return server_and_media_id
+
+    def _access_media(self, server_and_media_id, expect_success=True):
+        """
+        Try to access a media and check the result
+        """
+        download_resource = self.media_repo.children[b"download"]
+
+        media_id = server_and_media_id.split("/")[1]
+        local_path = self.filepaths.local_media_filepath(media_id)
+
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(download_resource),
+            "GET",
+            server_and_media_id,
+            shorthand=False,
+            access_token=self.admin_user_tok,
+        )
+
+        if expect_success:
+            self.assertEqual(
+                200,
+                channel.code,
+                msg=(
+                    "Expected to receive a 200 on accessing media: %s"
+                    % server_and_media_id
+                ),
+            )
+            # Test that the file exists
+            self.assertTrue(os.path.exists(local_path))
+        else:
+            self.assertEqual(
+                404,
+                channel.code,
+                msg=(
+                    "Expected to receive a 404 on accessing deleted media: %s"
+                    % (server_and_media_id)
+                ),
+            )
+            # Test that the file is deleted
+            self.assertFalse(os.path.exists(local_path))
diff --git a/tests/rest/admin/test_room.py b/tests/rest/admin/test_room.py
index 6dfc709dc5..46933a0493 100644
--- a/tests/rest/admin/test_room.py
+++ b/tests/rest/admin/test_room.py
@@ -78,14 +78,13 @@ class ShutdownRoomTestCase(unittest.HomeserverTestCase):
         )
 
         # Test that the admin can still send shutdown
-        url = "admin/shutdown_room/" + room_id
+        url = "/_synapse/admin/v1/shutdown_room/" + room_id
         request, channel = self.make_request(
             "POST",
             url.encode("ascii"),
             json.dumps({"new_room_user_id": self.admin_user}),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
@@ -110,18 +109,16 @@ class ShutdownRoomTestCase(unittest.HomeserverTestCase):
             json.dumps({"history_visibility": "world_readable"}),
             access_token=self.other_user_token,
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Test that the admin can still send shutdown
-        url = "admin/shutdown_room/" + room_id
+        url = "/_synapse/admin/v1/shutdown_room/" + room_id
         request, channel = self.make_request(
             "POST",
             url.encode("ascii"),
             json.dumps({"new_room_user_id": self.admin_user}),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
@@ -136,7 +133,6 @@ class ShutdownRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok
         )
-        self.render(request)
         self.assertEqual(
             expect_code, int(channel.result["code"]), msg=channel.result["body"]
         )
@@ -145,7 +141,6 @@ class ShutdownRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok
         )
-        self.render(request)
         self.assertEqual(
             expect_code, int(channel.result["code"]), msg=channel.result["body"]
         )
@@ -192,7 +187,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", self.url, json.dumps({}), access_token=self.other_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -206,7 +200,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url, json.dumps({}), access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
@@ -220,7 +213,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url, json.dumps({}), access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(
@@ -239,7 +231,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertIn("new_room_id", channel.json_body)
@@ -259,7 +250,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(
@@ -278,7 +268,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.BAD_JSON, channel.json_body["errcode"])
@@ -295,7 +284,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.BAD_JSON, channel.json_body["errcode"])
@@ -322,7 +310,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(None, channel.json_body["new_room_id"])
@@ -356,7 +343,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(None, channel.json_body["new_room_id"])
@@ -391,7 +377,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(None, channel.json_body["new_room_id"])
@@ -439,7 +424,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             json.dumps({"new_room_user_id": self.admin_user}),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(self.other_user, channel.json_body["kicked_users"][0])
@@ -470,7 +454,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             json.dumps({"history_visibility": "world_readable"}),
             access_token=self.other_user_tok,
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Test that room is not purged
@@ -488,7 +471,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             json.dumps({"new_room_user_id": self.admin_user}),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(self.other_user, channel.json_body["kicked_users"][0])
@@ -531,40 +513,7 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
     def _is_purged(self, room_id):
         """Test that the following tables have been purged of all rows related to the room.
         """
-        for table in (
-            "current_state_events",
-            "event_backward_extremities",
-            "event_forward_extremities",
-            "event_json",
-            "event_push_actions",
-            "event_search",
-            "events",
-            "group_rooms",
-            "public_room_list_stream",
-            "receipts_graph",
-            "receipts_linearized",
-            "room_aliases",
-            "room_depth",
-            "room_memberships",
-            "room_stats_state",
-            "room_stats_current",
-            "room_stats_historical",
-            "room_stats_earliest_token",
-            "rooms",
-            "stream_ordering_to_exterm",
-            "users_in_public_rooms",
-            "users_who_share_private_rooms",
-            "appservice_room_list",
-            "e2e_room_keys",
-            "event_push_summary",
-            "pusher_throttle",
-            "group_summary_rooms",
-            "local_invites",
-            "room_account_data",
-            "room_tags",
-            # "state_groups",  # Current impl leaves orphaned state groups around.
-            "state_groups_state",
-        ):
+        for table in PURGE_TABLES:
             count = self.get_success(
                 self.store.db_pool.simple_select_one_onecol(
                     table=table,
@@ -584,7 +533,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok
         )
-        self.render(request)
         self.assertEqual(
             expect_code, int(channel.result["code"]), msg=channel.result["body"]
         )
@@ -593,7 +541,6 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok
         )
-        self.render(request)
         self.assertEqual(
             expect_code, int(channel.result["code"]), msg=channel.result["body"]
         )
@@ -628,44 +575,11 @@ class PurgeRoomTestCase(unittest.HomeserverTestCase):
             {"room_id": room_id},
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Test that the following tables have been purged of all rows related to the room.
-        for table in (
-            "current_state_events",
-            "event_backward_extremities",
-            "event_forward_extremities",
-            "event_json",
-            "event_push_actions",
-            "event_search",
-            "events",
-            "group_rooms",
-            "public_room_list_stream",
-            "receipts_graph",
-            "receipts_linearized",
-            "room_aliases",
-            "room_depth",
-            "room_memberships",
-            "room_stats_state",
-            "room_stats_current",
-            "room_stats_historical",
-            "room_stats_earliest_token",
-            "rooms",
-            "stream_ordering_to_exterm",
-            "users_in_public_rooms",
-            "users_who_share_private_rooms",
-            "appservice_room_list",
-            "e2e_room_keys",
-            "event_push_summary",
-            "pusher_throttle",
-            "group_summary_rooms",
-            "room_account_data",
-            "room_tags",
-            # "state_groups",  # Current impl leaves orphaned state groups around.
-            "state_groups_state",
-        ):
+        for table in PURGE_TABLES:
             count = self.get_success(
                 self.store.db_pool.simple_select_one_onecol(
                     table=table,
@@ -712,7 +626,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         # Check request completed successfully
         self.assertEqual(200, int(channel.code), msg=channel.json_body)
@@ -794,7 +707,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
             request, channel = self.make_request(
                 "GET", url.encode("ascii"), access_token=self.admin_user_tok,
             )
-            self.render(request)
             self.assertEqual(
                 200, int(channel.result["code"]), msg=channel.result["body"]
             )
@@ -835,7 +747,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok,
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
     def test_correct_room_attributes(self):
@@ -859,7 +770,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
             {"room_id": room_id},
             access_token=self.admin_user_tok,
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Set this new alias as the canonical alias for this room
@@ -887,7 +797,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok,
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Check that rooms were returned
@@ -932,7 +841,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
                 {"room_id": room_id},
                 access_token=admin_user_tok,
             )
-            self.render(request)
             self.assertEqual(
                 200, int(channel.result["code"]), msg=channel.result["body"]
             )
@@ -970,7 +878,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
             request, channel = self.make_request(
                 "GET", url.encode("ascii"), access_token=self.admin_user_tok,
             )
-            self.render(request)
             self.assertEqual(200, channel.code, msg=channel.json_body)
 
             # Check that rooms were returned
@@ -1107,7 +1014,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
             request, channel = self.make_request(
                 "GET", url.encode("ascii"), access_token=self.admin_user_tok,
             )
-            self.render(request)
             self.assertEqual(expected_http_code, channel.code, msg=channel.json_body)
 
             if expected_http_code != 200:
@@ -1169,7 +1075,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok,
         )
-        self.render(request)
         self.assertEqual(200, channel.code, msg=channel.json_body)
 
         self.assertIn("room_id", channel.json_body)
@@ -1217,7 +1122,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok,
         )
-        self.render(request)
         self.assertEqual(200, channel.code, msg=channel.json_body)
 
         self.assertCountEqual(
@@ -1229,7 +1133,6 @@ class RoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url.encode("ascii"), access_token=self.admin_user_tok,
         )
-        self.render(request)
         self.assertEqual(200, channel.code, msg=channel.json_body)
 
         self.assertCountEqual(
@@ -1273,7 +1176,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.second_tok,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -1290,7 +1192,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
@@ -1307,7 +1208,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
@@ -1324,7 +1224,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(
@@ -1345,7 +1244,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("No known servers", channel.json_body["error"])
@@ -1363,7 +1261,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(
@@ -1383,7 +1280,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(self.public_room_id, channel.json_body["room_id"])
@@ -1393,7 +1289,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/joined_rooms", access_token=self.second_tok,
         )
-        self.render(request)
         self.assertEquals(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(self.public_room_id, channel.json_body["joined_rooms"][0])
 
@@ -1414,7 +1309,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -1442,7 +1336,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/joined_rooms", access_token=self.admin_user_tok,
         )
-        self.render(request)
         self.assertEquals(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(private_room_id, channel.json_body["joined_rooms"][0])
 
@@ -1457,7 +1350,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(private_room_id, channel.json_body["room_id"])
 
@@ -1466,7 +1358,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/joined_rooms", access_token=self.second_tok,
         )
-        self.render(request)
         self.assertEquals(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(private_room_id, channel.json_body["joined_rooms"][0])
 
@@ -1487,7 +1378,6 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             content=body.encode(encoding="utf_8"),
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(private_room_id, channel.json_body["room_id"])
@@ -1497,6 +1387,41 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/joined_rooms", access_token=self.second_tok,
         )
-        self.render(request)
         self.assertEquals(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(private_room_id, channel.json_body["joined_rooms"][0])
+
+
+PURGE_TABLES = [
+    "current_state_events",
+    "event_backward_extremities",
+    "event_forward_extremities",
+    "event_json",
+    "event_push_actions",
+    "event_search",
+    "events",
+    "group_rooms",
+    "public_room_list_stream",
+    "receipts_graph",
+    "receipts_linearized",
+    "room_aliases",
+    "room_depth",
+    "room_memberships",
+    "room_stats_state",
+    "room_stats_current",
+    "room_stats_historical",
+    "room_stats_earliest_token",
+    "rooms",
+    "stream_ordering_to_exterm",
+    "users_in_public_rooms",
+    "users_who_share_private_rooms",
+    "appservice_room_list",
+    "e2e_room_keys",
+    "event_push_summary",
+    "pusher_throttle",
+    "group_summary_rooms",
+    "local_invites",
+    "room_account_data",
+    "room_tags",
+    # "state_groups",  # Current impl leaves orphaned state groups around.
+    "state_groups_state",
+]
diff --git a/tests/rest/admin/test_statistics.py b/tests/rest/admin/test_statistics.py
new file mode 100644
index 0000000000..907b49f889
--- /dev/null
+++ b/tests/rest/admin/test_statistics.py
@@ -0,0 +1,458 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 Dirk Klimpel
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import json
+from binascii import unhexlify
+from typing import Any, Dict, List, Optional
+
+import synapse.rest.admin
+from synapse.api.errors import Codes
+from synapse.rest.client.v1 import login
+
+from tests import unittest
+
+
+class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.store = hs.get_datastore()
+        self.media_repo = hs.get_media_repository_resource()
+
+        self.admin_user = self.register_user("admin", "pass", admin=True)
+        self.admin_user_tok = self.login("admin", "pass")
+
+        self.other_user = self.register_user("user", "pass")
+        self.other_user_tok = self.login("user", "pass")
+
+        self.url = "/_synapse/admin/v1/statistics/users/media"
+
+    def test_no_auth(self):
+        """
+        Try to list users without authentication.
+        """
+        request, channel = self.make_request("GET", self.url, b"{}")
+
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
+    def test_requester_is_no_admin(self):
+        """
+        If the user is not a server admin, an error 403 is returned.
+        """
+        request, channel = self.make_request(
+            "GET", self.url, json.dumps({}), access_token=self.other_user_tok,
+        )
+
+        self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
+
+    def test_invalid_parameter(self):
+        """
+        If parameters are invalid, an error is returned.
+        """
+        # unkown order_by
+        request, channel = self.make_request(
+            "GET", self.url + "?order_by=bar", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+        # negative from
+        request, channel = self.make_request(
+            "GET", self.url + "?from=-5", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+        # negative limit
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=-5", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+        # negative from_ts
+        request, channel = self.make_request(
+            "GET", self.url + "?from_ts=-1234", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+        # negative until_ts
+        request, channel = self.make_request(
+            "GET", self.url + "?until_ts=-1234", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+        # until_ts smaller from_ts
+        request, channel = self.make_request(
+            "GET",
+            self.url + "?from_ts=10&until_ts=5",
+            access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+        # empty search term
+        request, channel = self.make_request(
+            "GET", self.url + "?search_term=", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+        # invalid search order
+        request, channel = self.make_request(
+            "GET", self.url + "?dir=bar", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+    def test_limit(self):
+        """
+        Testing list of media with limit
+        """
+        self._create_users_with_media(10, 2)
+
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=5", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], 10)
+        self.assertEqual(len(channel.json_body["users"]), 5)
+        self.assertEqual(channel.json_body["next_token"], 5)
+        self._check_fields(channel.json_body["users"])
+
+    def test_from(self):
+        """
+        Testing list of media with a defined starting point (from)
+        """
+        self._create_users_with_media(20, 2)
+
+        request, channel = self.make_request(
+            "GET", self.url + "?from=5", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], 20)
+        self.assertEqual(len(channel.json_body["users"]), 15)
+        self.assertNotIn("next_token", channel.json_body)
+        self._check_fields(channel.json_body["users"])
+
+    def test_limit_and_from(self):
+        """
+        Testing list of media with a defined starting point and limit
+        """
+        self._create_users_with_media(20, 2)
+
+        request, channel = self.make_request(
+            "GET", self.url + "?from=5&limit=10", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], 20)
+        self.assertEqual(channel.json_body["next_token"], 15)
+        self.assertEqual(len(channel.json_body["users"]), 10)
+        self._check_fields(channel.json_body["users"])
+
+    def test_next_token(self):
+        """
+        Testing that `next_token` appears at the right place
+        """
+
+        number_users = 20
+        self._create_users_with_media(number_users, 3)
+
+        #  `next_token` does not appear
+        # Number of results is the number of entries
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=20", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_users)
+        self.assertEqual(len(channel.json_body["users"]), number_users)
+        self.assertNotIn("next_token", channel.json_body)
+
+        #  `next_token` does not appear
+        # Number of max results is larger than the number of entries
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=21", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_users)
+        self.assertEqual(len(channel.json_body["users"]), number_users)
+        self.assertNotIn("next_token", channel.json_body)
+
+        #  `next_token` does appear
+        # Number of max results is smaller than the number of entries
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=19", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_users)
+        self.assertEqual(len(channel.json_body["users"]), 19)
+        self.assertEqual(channel.json_body["next_token"], 19)
+
+        # Set `from` to value of `next_token` for request remaining entries
+        # Check `next_token` does not appear
+        request, channel = self.make_request(
+            "GET", self.url + "?from=19", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_users)
+        self.assertEqual(len(channel.json_body["users"]), 1)
+        self.assertNotIn("next_token", channel.json_body)
+
+    def test_no_media(self):
+        """
+        Tests that a normal lookup for statistics is successfully
+        if users have no media created
+        """
+
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(0, channel.json_body["total"])
+        self.assertEqual(0, len(channel.json_body["users"]))
+
+    def test_order_by(self):
+        """
+        Testing order list with parameter `order_by`
+        """
+
+        # create users
+        self.register_user("user_a", "pass", displayname="UserZ")
+        userA_tok = self.login("user_a", "pass")
+        self._create_media(userA_tok, 1)
+
+        self.register_user("user_b", "pass", displayname="UserY")
+        userB_tok = self.login("user_b", "pass")
+        self._create_media(userB_tok, 3)
+
+        self.register_user("user_c", "pass", displayname="UserX")
+        userC_tok = self.login("user_c", "pass")
+        self._create_media(userC_tok, 2)
+
+        # order by user_id
+        self._order_test("user_id", ["@user_a:test", "@user_b:test", "@user_c:test"])
+        self._order_test(
+            "user_id", ["@user_a:test", "@user_b:test", "@user_c:test"], "f",
+        )
+        self._order_test(
+            "user_id", ["@user_c:test", "@user_b:test", "@user_a:test"], "b",
+        )
+
+        # order by displayname
+        self._order_test(
+            "displayname", ["@user_c:test", "@user_b:test", "@user_a:test"]
+        )
+        self._order_test(
+            "displayname", ["@user_c:test", "@user_b:test", "@user_a:test"], "f",
+        )
+        self._order_test(
+            "displayname", ["@user_a:test", "@user_b:test", "@user_c:test"], "b",
+        )
+
+        # order by media_length
+        self._order_test(
+            "media_length", ["@user_a:test", "@user_c:test", "@user_b:test"],
+        )
+        self._order_test(
+            "media_length", ["@user_a:test", "@user_c:test", "@user_b:test"], "f",
+        )
+        self._order_test(
+            "media_length", ["@user_b:test", "@user_c:test", "@user_a:test"], "b",
+        )
+
+        # order by media_count
+        self._order_test(
+            "media_count", ["@user_a:test", "@user_c:test", "@user_b:test"],
+        )
+        self._order_test(
+            "media_count", ["@user_a:test", "@user_c:test", "@user_b:test"], "f",
+        )
+        self._order_test(
+            "media_count", ["@user_b:test", "@user_c:test", "@user_a:test"], "b",
+        )
+
+    def test_from_until_ts(self):
+        """
+        Testing filter by time with parameters `from_ts` and `until_ts`
+        """
+        # create media earlier than `ts1` to ensure that `from_ts` is working
+        self._create_media(self.other_user_tok, 3)
+        self.pump(1)
+        ts1 = self.clock.time_msec()
+
+        # list all media when filter is not set
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["users"][0]["media_count"], 3)
+
+        # filter media starting at `ts1` after creating first media
+        # result is 0
+        request, channel = self.make_request(
+            "GET", self.url + "?from_ts=%s" % (ts1,), access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], 0)
+
+        self._create_media(self.other_user_tok, 3)
+        self.pump(1)
+        ts2 = self.clock.time_msec()
+        # create media after `ts2` to ensure that `until_ts` is working
+        self._create_media(self.other_user_tok, 3)
+
+        # filter media between `ts1` and `ts2`
+        request, channel = self.make_request(
+            "GET",
+            self.url + "?from_ts=%s&until_ts=%s" % (ts1, ts2),
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["users"][0]["media_count"], 3)
+
+        # filter media until `ts2` and earlier
+        request, channel = self.make_request(
+            "GET", self.url + "?until_ts=%s" % (ts2,), access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["users"][0]["media_count"], 6)
+
+    def test_search_term(self):
+        self._create_users_with_media(20, 1)
+
+        # check without filter get all users
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], 20)
+
+        # filter user 1 and 10-19 by `user_id`
+        request, channel = self.make_request(
+            "GET",
+            self.url + "?search_term=foo_user_1",
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], 11)
+
+        # filter on this user in `displayname`
+        request, channel = self.make_request(
+            "GET",
+            self.url + "?search_term=bar_user_10",
+            access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["users"][0]["displayname"], "bar_user_10")
+        self.assertEqual(channel.json_body["total"], 1)
+
+        # filter and get empty result
+        request, channel = self.make_request(
+            "GET", self.url + "?search_term=foobar", access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], 0)
+
+    def _create_users_with_media(self, number_users: int, media_per_user: int):
+        """
+        Create a number of users with a number of media
+        Args:
+            number_users: Number of users to be created
+            media_per_user: Number of media to be created for each user
+        """
+        for i in range(number_users):
+            self.register_user("foo_user_%s" % i, "pass", displayname="bar_user_%s" % i)
+            user_tok = self.login("foo_user_%s" % i, "pass")
+            self._create_media(user_tok, media_per_user)
+
+    def _create_media(self, user_token: str, number_media: int):
+        """
+        Create a number of media for a specific user
+        Args:
+            user_token: Access token of the user
+            number_media: Number of media to be created for the user
+        """
+        upload_resource = self.media_repo.children[b"upload"]
+        for i in range(number_media):
+            # file size is 67 Byte
+            image_data = unhexlify(
+                b"89504e470d0a1a0a0000000d4948445200000001000000010806"
+                b"0000001f15c4890000000a49444154789c63000100000500010d"
+                b"0a2db40000000049454e44ae426082"
+            )
+
+            # Upload some media into the room
+            self.helper.upload_media(
+                upload_resource, image_data, tok=user_token, expect_code=200
+            )
+
+    def _check_fields(self, content: List[Dict[str, Any]]):
+        """Checks that all attributes are present in content
+        Args:
+            content: List that is checked for content
+        """
+        for c in content:
+            self.assertIn("user_id", c)
+            self.assertIn("displayname", c)
+            self.assertIn("media_count", c)
+            self.assertIn("media_length", c)
+
+    def _order_test(
+        self, order_type: str, expected_user_list: List[str], dir: Optional[str] = None
+    ):
+        """Request the list of users in a certain order. Assert that order is what
+        we expect
+        Args:
+            order_type: The type of ordering to give the server
+            expected_user_list: The list of user_ids in the order we expect to get
+                back from the server
+            dir: The direction of ordering to give the server
+        """
+
+        url = self.url + "?order_by=%s" % (order_type,)
+        if dir is not None and dir in ("b", "f"):
+            url += "&dir=%s" % (dir,)
+        request, channel = self.make_request(
+            "GET", url.encode("ascii"), access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(channel.json_body["total"], len(expected_user_list))
+
+        returned_order = [row["user_id"] for row in channel.json_body["users"]]
+        self.assertListEqual(expected_user_list, returned_order)
+        self._check_fields(channel.json_body["users"])
diff --git a/tests/rest/admin/test_user.py b/tests/rest/admin/test_user.py
index 98d0623734..54d46f4bd3 100644
--- a/tests/rest/admin/test_user.py
+++ b/tests/rest/admin/test_user.py
@@ -17,14 +17,15 @@ import hashlib
 import hmac
 import json
 import urllib.parse
+from binascii import unhexlify
 
 from mock import Mock
 
 import synapse.rest.admin
 from synapse.api.constants import UserTypes
 from synapse.api.errors import Codes, HttpResponseException, ResourceLimitError
-from synapse.rest.client.v1 import login, room
-from synapse.rest.client.v2_alpha import sync
+from synapse.rest.client.v1 import login, logout, profile, room
+from synapse.rest.client.v2_alpha import devices, sync
 
 from tests import unittest
 from tests.test_utils import make_awaitable
@@ -33,11 +34,14 @@ from tests.unittest import override_config
 
 class UserRegisterTestCase(unittest.HomeserverTestCase):
 
-    servlets = [synapse.rest.admin.register_servlets_for_client_rest_resource]
+    servlets = [
+        synapse.rest.admin.register_servlets_for_client_rest_resource,
+        profile.register_servlets,
+    ]
 
     def make_homeserver(self, reactor, clock):
 
-        self.url = "/_matrix/client/r0/admin/register"
+        self.url = "/_synapse/admin/v1/register"
 
         self.registration_handler = Mock()
         self.identity_handler = Mock()
@@ -67,7 +71,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         self.hs.config.registration_shared_secret = None
 
         request, channel = self.make_request("POST", self.url, b"{}")
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(
@@ -85,7 +88,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         self.hs.get_secrets = Mock(return_value=secrets)
 
         request, channel = self.make_request("GET", self.url)
-        self.render(request)
 
         self.assertEqual(channel.json_body, {"nonce": "abcd"})
 
@@ -95,7 +97,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         only last for SALT_TIMEOUT (60s).
         """
         request, channel = self.make_request("GET", self.url)
-        self.render(request)
         nonce = channel.json_body["nonce"]
 
         # 59 seconds
@@ -103,7 +104,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
 
         body = json.dumps({"nonce": nonce})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("username must be specified", channel.json_body["error"])
@@ -112,7 +112,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         self.reactor.advance(2)
 
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("unrecognised nonce", channel.json_body["error"])
@@ -122,7 +121,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         Only the provided nonce can be used, as it's checked in the MAC.
         """
         request, channel = self.make_request("GET", self.url)
-        self.render(request)
         nonce = channel.json_body["nonce"]
 
         want_mac = hmac.new(key=b"shared", digestmod=hashlib.sha1)
@@ -139,7 +137,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
             }
         )
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("HMAC incorrect", channel.json_body["error"])
@@ -150,7 +147,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         user is registered.
         """
         request, channel = self.make_request("GET", self.url)
-        self.render(request)
         nonce = channel.json_body["nonce"]
 
         want_mac = hmac.new(key=b"shared", digestmod=hashlib.sha1)
@@ -170,7 +166,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
             }
         )
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["user_id"])
@@ -180,7 +175,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         A valid unrecognised nonce.
         """
         request, channel = self.make_request("GET", self.url)
-        self.render(request)
         nonce = channel.json_body["nonce"]
 
         want_mac = hmac.new(key=b"shared", digestmod=hashlib.sha1)
@@ -197,14 +191,12 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
             }
         )
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["user_id"])
 
         # Now, try and reuse it
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("unrecognised nonce", channel.json_body["error"])
@@ -218,7 +210,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
 
         def nonce():
             request, channel = self.make_request("GET", self.url)
-            self.render(request)
             return channel.json_body["nonce"]
 
         #
@@ -228,7 +219,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must be present
         body = json.dumps({})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("nonce must be specified", channel.json_body["error"])
@@ -240,7 +230,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must be present
         body = json.dumps({"nonce": nonce()})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("username must be specified", channel.json_body["error"])
@@ -248,7 +237,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must be a string
         body = json.dumps({"nonce": nonce(), "username": 1234})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("Invalid username", channel.json_body["error"])
@@ -256,7 +244,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must not have null bytes
         body = json.dumps({"nonce": nonce(), "username": "abcd\u0000"})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("Invalid username", channel.json_body["error"])
@@ -264,7 +251,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must not have null bytes
         body = json.dumps({"nonce": nonce(), "username": "a" * 1000})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("Invalid username", channel.json_body["error"])
@@ -276,7 +262,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must be present
         body = json.dumps({"nonce": nonce(), "username": "a"})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("password must be specified", channel.json_body["error"])
@@ -284,7 +269,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must be a string
         body = json.dumps({"nonce": nonce(), "username": "a", "password": 1234})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("Invalid password", channel.json_body["error"])
@@ -292,7 +276,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must not have null bytes
         body = json.dumps({"nonce": nonce(), "username": "a", "password": "abcd\u0000"})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("Invalid password", channel.json_body["error"])
@@ -300,7 +283,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Super long
         body = json.dumps({"nonce": nonce(), "username": "a", "password": "A" * 1000})
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("Invalid password", channel.json_body["error"])
@@ -319,11 +301,112 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
             }
         )
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("Invalid user type", channel.json_body["error"])
 
+    def test_displayname(self):
+        """
+        Test that displayname of new user is set
+        """
+
+        # set no displayname
+        request, channel = self.make_request("GET", self.url)
+        nonce = channel.json_body["nonce"]
+
+        want_mac = hmac.new(key=b"shared", digestmod=hashlib.sha1)
+        want_mac.update(nonce.encode("ascii") + b"\x00bob1\x00abc123\x00notadmin")
+        want_mac = want_mac.hexdigest()
+
+        body = json.dumps(
+            {"nonce": nonce, "username": "bob1", "password": "abc123", "mac": want_mac}
+        )
+        request, channel = self.make_request("POST", self.url, body.encode("utf8"))
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual("@bob1:test", channel.json_body["user_id"])
+
+        request, channel = self.make_request("GET", "/profile/@bob1:test/displayname")
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual("bob1", channel.json_body["displayname"])
+
+        # displayname is None
+        request, channel = self.make_request("GET", self.url)
+        nonce = channel.json_body["nonce"]
+
+        want_mac = hmac.new(key=b"shared", digestmod=hashlib.sha1)
+        want_mac.update(nonce.encode("ascii") + b"\x00bob2\x00abc123\x00notadmin")
+        want_mac = want_mac.hexdigest()
+
+        body = json.dumps(
+            {
+                "nonce": nonce,
+                "username": "bob2",
+                "displayname": None,
+                "password": "abc123",
+                "mac": want_mac,
+            }
+        )
+        request, channel = self.make_request("POST", self.url, body.encode("utf8"))
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual("@bob2:test", channel.json_body["user_id"])
+
+        request, channel = self.make_request("GET", "/profile/@bob2:test/displayname")
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual("bob2", channel.json_body["displayname"])
+
+        # displayname is empty
+        request, channel = self.make_request("GET", self.url)
+        nonce = channel.json_body["nonce"]
+
+        want_mac = hmac.new(key=b"shared", digestmod=hashlib.sha1)
+        want_mac.update(nonce.encode("ascii") + b"\x00bob3\x00abc123\x00notadmin")
+        want_mac = want_mac.hexdigest()
+
+        body = json.dumps(
+            {
+                "nonce": nonce,
+                "username": "bob3",
+                "displayname": "",
+                "password": "abc123",
+                "mac": want_mac,
+            }
+        )
+        request, channel = self.make_request("POST", self.url, body.encode("utf8"))
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual("@bob3:test", channel.json_body["user_id"])
+
+        request, channel = self.make_request("GET", "/profile/@bob3:test/displayname")
+        self.assertEqual(404, int(channel.result["code"]), msg=channel.result["body"])
+
+        # set displayname
+        request, channel = self.make_request("GET", self.url)
+        nonce = channel.json_body["nonce"]
+
+        want_mac = hmac.new(key=b"shared", digestmod=hashlib.sha1)
+        want_mac.update(nonce.encode("ascii") + b"\x00bob4\x00abc123\x00notadmin")
+        want_mac = want_mac.hexdigest()
+
+        body = json.dumps(
+            {
+                "nonce": nonce,
+                "username": "bob4",
+                "displayname": "Bob's Name",
+                "password": "abc123",
+                "mac": want_mac,
+            }
+        )
+        request, channel = self.make_request("POST", self.url, body.encode("utf8"))
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual("@bob4:test", channel.json_body["user_id"])
+
+        request, channel = self.make_request("GET", "/profile/@bob4:test/displayname")
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual("Bob's Name", channel.json_body["displayname"])
+
     @override_config(
         {"limit_usage_by_mau": True, "max_mau_value": 2, "mau_trial_days": 0}
     )
@@ -347,7 +430,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
 
         # Register new user with admin API
         request, channel = self.make_request("GET", self.url)
-        self.render(request)
         nonce = channel.json_body["nonce"]
 
         want_mac = hmac.new(key=b"shared", digestmod=hashlib.sha1)
@@ -367,7 +449,6 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
             }
         )
         request, channel = self.make_request("POST", self.url, body.encode("utf8"))
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["user_id"])
@@ -393,7 +474,6 @@ class UsersListTestCase(unittest.HomeserverTestCase):
         Try to list users without authentication.
         """
         request, channel = self.make_request("GET", self.url, b"{}")
-        self.render(request)
 
         self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("M_MISSING_TOKEN", channel.json_body["errcode"])
@@ -408,7 +488,6 @@ class UsersListTestCase(unittest.HomeserverTestCase):
             b"{}",
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(3, len(channel.json_body["users"]))
@@ -444,7 +523,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.other_user_token,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("You are not a server admin", channel.json_body["error"])
@@ -452,7 +530,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", url, access_token=self.other_user_token, content=b"{}",
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("You are not a server admin", channel.json_body["error"])
@@ -467,7 +544,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             "/_synapse/admin/v2/users/@unknown_person:test",
             access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual("M_NOT_FOUND", channel.json_body["errcode"])
@@ -495,7 +571,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(201, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -508,7 +583,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -541,7 +615,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(201, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -554,7 +627,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -582,7 +654,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/sync", access_token=self.admin_user_tok
         )
-        self.render(request)
 
         if channel.code != 200:
             raise HttpResponseException(
@@ -611,7 +682,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(201, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -651,7 +721,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         # Admin user is not blocked by mau anymore
         self.assertEqual(201, int(channel.result["code"]), msg=channel.result["body"])
@@ -689,7 +758,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(201, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -734,7 +802,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(201, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -761,7 +828,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
@@ -779,7 +845,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@user:test", channel.json_body["name"])
@@ -789,7 +854,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url_other_user, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@user:test", channel.json_body["name"])
@@ -811,7 +875,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@user:test", channel.json_body["name"])
@@ -822,7 +885,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url_other_user, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@user:test", channel.json_body["name"])
@@ -843,7 +905,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@user:test", channel.json_body["name"])
@@ -854,7 +915,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url_other_user, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@user:test", channel.json_body["name"])
@@ -872,7 +932,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=json.dumps({"deactivated": True}).encode(encoding="utf_8"),
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self._is_erased("@user:test", False)
         d = self.store.mark_user_erased("@user:test")
@@ -886,7 +945,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=json.dumps({"deactivated": False}).encode(encoding="utf_8"),
         )
-        self.render(request)
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
 
         # Reactivate the user.
@@ -898,14 +956,12 @@ class UserRestTestCase(unittest.HomeserverTestCase):
                 encoding="utf_8"
             ),
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Get user
         request, channel = self.make_request(
             "GET", self.url_other_user, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@user:test", channel.json_body["name"])
@@ -926,7 +982,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@user:test", channel.json_body["name"])
@@ -936,7 +991,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url_other_user, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@user:test", channel.json_body["name"])
@@ -958,7 +1012,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(201, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -968,7 +1021,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -984,7 +1036,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content=body.encode(encoding="utf_8"),
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
 
@@ -992,7 +1043,6 @@ class UserRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("@bob:test", channel.json_body["name"])
@@ -1016,7 +1066,6 @@ class UserMembershipRestTestCase(unittest.HomeserverTestCase):
     servlets = [
         synapse.rest.admin.register_servlets,
         login.register_servlets,
-        sync.register_servlets,
         room.register_servlets,
     ]
 
@@ -1036,7 +1085,6 @@ class UserMembershipRestTestCase(unittest.HomeserverTestCase):
         Try to list rooms of an user without authentication.
         """
         request, channel = self.make_request("GET", self.url, b"{}")
-        self.render(request)
 
         self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
@@ -1050,7 +1098,6 @@ class UserMembershipRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=other_user_token,
         )
-        self.render(request)
 
         self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -1063,7 +1110,6 @@ class UserMembershipRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
@@ -1077,11 +1123,24 @@ class UserMembershipRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only lookup local users", channel.json_body["error"])
 
+    def test_no_memberships(self):
+        """
+        Tests that a normal lookup for rooms is successfully
+        if user has no memberships
+        """
+        # Get rooms
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(0, channel.json_body["total"])
+        self.assertEqual(0, len(channel.json_body["joined_rooms"]))
+
     def test_get_rooms(self):
         """
         Tests that a normal lookup for rooms is successfully
@@ -1096,8 +1155,724 @@ class UserMembershipRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url, access_token=self.admin_user_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, channel.code, msg=channel.json_body)
         self.assertEqual(number_rooms, channel.json_body["total"])
         self.assertEqual(number_rooms, len(channel.json_body["joined_rooms"]))
+
+
+class PushersRestTestCase(unittest.HomeserverTestCase):
+
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.store = hs.get_datastore()
+
+        self.admin_user = self.register_user("admin", "pass", admin=True)
+        self.admin_user_tok = self.login("admin", "pass")
+
+        self.other_user = self.register_user("user", "pass")
+        self.url = "/_synapse/admin/v1/users/%s/pushers" % urllib.parse.quote(
+            self.other_user
+        )
+
+    def test_no_auth(self):
+        """
+        Try to list pushers of an user without authentication.
+        """
+        request, channel = self.make_request("GET", self.url, b"{}")
+
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
+    def test_requester_is_no_admin(self):
+        """
+        If the user is not a server admin, an error is returned.
+        """
+        other_user_token = self.login("user", "pass")
+
+        request, channel = self.make_request(
+            "GET", self.url, access_token=other_user_token,
+        )
+
+        self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
+
+    def test_user_does_not_exist(self):
+        """
+        Tests that a lookup for a user that does not exist returns a 404
+        """
+        url = "/_synapse/admin/v1/users/@unknown_person:test/pushers"
+        request, channel = self.make_request(
+            "GET", url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(404, channel.code, msg=channel.json_body)
+        self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
+
+    def test_user_is_not_local(self):
+        """
+        Tests that a lookup for a user that is not a local returns a 400
+        """
+        url = "/_synapse/admin/v1/users/@unknown_person:unknown_domain/pushers"
+
+        request, channel = self.make_request(
+            "GET", url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, channel.code, msg=channel.json_body)
+        self.assertEqual("Can only lookup local users", channel.json_body["error"])
+
+    def test_get_pushers(self):
+        """
+        Tests that a normal lookup for pushers is successfully
+        """
+
+        # Get pushers
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(0, channel.json_body["total"])
+
+        # Register the pusher
+        other_user_token = self.login("user", "pass")
+        user_tuple = self.get_success(
+            self.store.get_user_by_access_token(other_user_token)
+        )
+        token_id = user_tuple.token_id
+
+        self.get_success(
+            self.hs.get_pusherpool().add_pusher(
+                user_id=self.other_user,
+                access_token=token_id,
+                kind="http",
+                app_id="m.http",
+                app_display_name="HTTP Push Notifications",
+                device_display_name="pushy push",
+                pushkey="a@example.com",
+                lang=None,
+                data={"url": "example.com"},
+            )
+        )
+
+        # Get pushers
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(1, channel.json_body["total"])
+
+        for p in channel.json_body["pushers"]:
+            self.assertIn("pushkey", p)
+            self.assertIn("kind", p)
+            self.assertIn("app_id", p)
+            self.assertIn("app_display_name", p)
+            self.assertIn("device_display_name", p)
+            self.assertIn("profile_tag", p)
+            self.assertIn("lang", p)
+            self.assertIn("url", p["data"])
+
+
+class UserMediaRestTestCase(unittest.HomeserverTestCase):
+
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.store = hs.get_datastore()
+        self.media_repo = hs.get_media_repository_resource()
+
+        self.admin_user = self.register_user("admin", "pass", admin=True)
+        self.admin_user_tok = self.login("admin", "pass")
+
+        self.other_user = self.register_user("user", "pass")
+        self.url = "/_synapse/admin/v1/users/%s/media" % urllib.parse.quote(
+            self.other_user
+        )
+
+    def test_no_auth(self):
+        """
+        Try to list media of an user without authentication.
+        """
+        request, channel = self.make_request("GET", self.url, b"{}")
+
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
+    def test_requester_is_no_admin(self):
+        """
+        If the user is not a server admin, an error is returned.
+        """
+        other_user_token = self.login("user", "pass")
+
+        request, channel = self.make_request(
+            "GET", self.url, access_token=other_user_token,
+        )
+
+        self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
+
+    def test_user_does_not_exist(self):
+        """
+        Tests that a lookup for a user that does not exist returns a 404
+        """
+        url = "/_synapse/admin/v1/users/@unknown_person:test/media"
+        request, channel = self.make_request(
+            "GET", url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(404, channel.code, msg=channel.json_body)
+        self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
+
+    def test_user_is_not_local(self):
+        """
+        Tests that a lookup for a user that is not a local returns a 400
+        """
+        url = "/_synapse/admin/v1/users/@unknown_person:unknown_domain/media"
+
+        request, channel = self.make_request(
+            "GET", url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, channel.code, msg=channel.json_body)
+        self.assertEqual("Can only lookup local users", channel.json_body["error"])
+
+    def test_limit(self):
+        """
+        Testing list of media with limit
+        """
+
+        number_media = 20
+        other_user_tok = self.login("user", "pass")
+        self._create_media(other_user_tok, number_media)
+
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=5", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_media)
+        self.assertEqual(len(channel.json_body["media"]), 5)
+        self.assertEqual(channel.json_body["next_token"], 5)
+        self._check_fields(channel.json_body["media"])
+
+    def test_from(self):
+        """
+        Testing list of media with a defined starting point (from)
+        """
+
+        number_media = 20
+        other_user_tok = self.login("user", "pass")
+        self._create_media(other_user_tok, number_media)
+
+        request, channel = self.make_request(
+            "GET", self.url + "?from=5", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_media)
+        self.assertEqual(len(channel.json_body["media"]), 15)
+        self.assertNotIn("next_token", channel.json_body)
+        self._check_fields(channel.json_body["media"])
+
+    def test_limit_and_from(self):
+        """
+        Testing list of media with a defined starting point and limit
+        """
+
+        number_media = 20
+        other_user_tok = self.login("user", "pass")
+        self._create_media(other_user_tok, number_media)
+
+        request, channel = self.make_request(
+            "GET", self.url + "?from=5&limit=10", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_media)
+        self.assertEqual(channel.json_body["next_token"], 15)
+        self.assertEqual(len(channel.json_body["media"]), 10)
+        self._check_fields(channel.json_body["media"])
+
+    def test_limit_is_negative(self):
+        """
+        Testing that a negative limit parameter returns a 400
+        """
+
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=-5", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+    def test_from_is_negative(self):
+        """
+        Testing that a negative from parameter returns a 400
+        """
+
+        request, channel = self.make_request(
+            "GET", self.url + "?from=-5", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
+
+    def test_next_token(self):
+        """
+        Testing that `next_token` appears at the right place
+        """
+
+        number_media = 20
+        other_user_tok = self.login("user", "pass")
+        self._create_media(other_user_tok, number_media)
+
+        #  `next_token` does not appear
+        # Number of results is the number of entries
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=20", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_media)
+        self.assertEqual(len(channel.json_body["media"]), number_media)
+        self.assertNotIn("next_token", channel.json_body)
+
+        #  `next_token` does not appear
+        # Number of max results is larger than the number of entries
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=21", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_media)
+        self.assertEqual(len(channel.json_body["media"]), number_media)
+        self.assertNotIn("next_token", channel.json_body)
+
+        #  `next_token` does appear
+        # Number of max results is smaller than the number of entries
+        request, channel = self.make_request(
+            "GET", self.url + "?limit=19", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_media)
+        self.assertEqual(len(channel.json_body["media"]), 19)
+        self.assertEqual(channel.json_body["next_token"], 19)
+
+        # Check
+        # Set `from` to value of `next_token` for request remaining entries
+        #  `next_token` does not appear
+        request, channel = self.make_request(
+            "GET", self.url + "?from=19", access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(channel.json_body["total"], number_media)
+        self.assertEqual(len(channel.json_body["media"]), 1)
+        self.assertNotIn("next_token", channel.json_body)
+
+    def test_user_has_no_media(self):
+        """
+        Tests that a normal lookup for media is successfully
+        if user has no media created
+        """
+
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(0, channel.json_body["total"])
+        self.assertEqual(0, len(channel.json_body["media"]))
+
+    def test_get_media(self):
+        """
+        Tests that a normal lookup for media is successfully
+        """
+
+        number_media = 5
+        other_user_tok = self.login("user", "pass")
+        self._create_media(other_user_tok, number_media)
+
+        request, channel = self.make_request(
+            "GET", self.url, access_token=self.admin_user_tok,
+        )
+
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(number_media, channel.json_body["total"])
+        self.assertEqual(number_media, len(channel.json_body["media"]))
+        self.assertNotIn("next_token", channel.json_body)
+        self._check_fields(channel.json_body["media"])
+
+    def _create_media(self, user_token, number_media):
+        """
+        Create a number of media for a specific user
+        """
+        upload_resource = self.media_repo.children[b"upload"]
+        for i in range(number_media):
+            # file size is 67 Byte
+            image_data = unhexlify(
+                b"89504e470d0a1a0a0000000d4948445200000001000000010806"
+                b"0000001f15c4890000000a49444154789c63000100000500010d"
+                b"0a2db40000000049454e44ae426082"
+            )
+
+            # Upload some media into the room
+            self.helper.upload_media(
+                upload_resource, image_data, tok=user_token, expect_code=200
+            )
+
+    def _check_fields(self, content):
+        """Checks that all attributes are present in content
+        """
+        for m in content:
+            self.assertIn("media_id", m)
+            self.assertIn("media_type", m)
+            self.assertIn("media_length", m)
+            self.assertIn("upload_name", m)
+            self.assertIn("created_ts", m)
+            self.assertIn("last_access_ts", m)
+            self.assertIn("quarantined_by", m)
+            self.assertIn("safe_from_quarantine", m)
+
+
+class UserTokenRestTestCase(unittest.HomeserverTestCase):
+    """Test for /_synapse/admin/v1/users/<user>/login
+    """
+
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+        sync.register_servlets,
+        room.register_servlets,
+        devices.register_servlets,
+        logout.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.store = hs.get_datastore()
+
+        self.admin_user = self.register_user("admin", "pass", admin=True)
+        self.admin_user_tok = self.login("admin", "pass")
+
+        self.other_user = self.register_user("user", "pass")
+        self.other_user_tok = self.login("user", "pass")
+        self.url = "/_synapse/admin/v1/users/%s/login" % urllib.parse.quote(
+            self.other_user
+        )
+
+    def _get_token(self) -> str:
+        request, channel = self.make_request(
+            "POST", self.url, b"{}", access_token=self.admin_user_tok
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+        return channel.json_body["access_token"]
+
+    def test_no_auth(self):
+        """Try to login as a user without authentication.
+        """
+        request, channel = self.make_request("POST", self.url, b"{}")
+
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
+    def test_not_admin(self):
+        """Try to login as a user as a non-admin user.
+        """
+        request, channel = self.make_request(
+            "POST", self.url, b"{}", access_token=self.other_user_tok
+        )
+
+        self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
+
+    def test_send_event(self):
+        """Test that sending event as a user works.
+        """
+        # Create a room.
+        room_id = self.helper.create_room_as(self.other_user, tok=self.other_user_tok)
+
+        # Login in as the user
+        puppet_token = self._get_token()
+
+        # Test that sending works, and generates the event as the right user.
+        resp = self.helper.send_event(room_id, "com.example.test", tok=puppet_token)
+        event_id = resp["event_id"]
+        event = self.get_success(self.store.get_event(event_id))
+        self.assertEqual(event.sender, self.other_user)
+
+    def test_devices(self):
+        """Tests that logging in as a user doesn't create a new device for them.
+        """
+        # Login in as the user
+        self._get_token()
+
+        # Check that we don't see a new device in our devices list
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=self.other_user_tok
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+        # We should only see the one device (from the login in `prepare`)
+        self.assertEqual(len(channel.json_body["devices"]), 1)
+
+    def test_logout(self):
+        """Test that calling `/logout` with the token works.
+        """
+        # Login in as the user
+        puppet_token = self._get_token()
+
+        # Test that we can successfully make a request
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=puppet_token
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+        # Logout with the puppet token
+        request, channel = self.make_request(
+            "POST", "logout", b"{}", access_token=puppet_token
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+        # The puppet token should no longer work
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=puppet_token
+        )
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+
+        # .. but the real user's tokens should still work
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=self.other_user_tok
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+    def test_user_logout_all(self):
+        """Tests that the target user calling `/logout/all` does *not* expire
+        the token.
+        """
+        # Login in as the user
+        puppet_token = self._get_token()
+
+        # Test that we can successfully make a request
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=puppet_token
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+        # Logout all with the real user token
+        request, channel = self.make_request(
+            "POST", "logout/all", b"{}", access_token=self.other_user_tok
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+        # The puppet token should still work
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=puppet_token
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+        # .. but the real user's tokens shouldn't
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=self.other_user_tok
+        )
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+
+    def test_admin_logout_all(self):
+        """Tests that the admin user calling `/logout/all` does expire the
+        token.
+        """
+        # Login in as the user
+        puppet_token = self._get_token()
+
+        # Test that we can successfully make a request
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=puppet_token
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+        # Logout all with the admin user token
+        request, channel = self.make_request(
+            "POST", "logout/all", b"{}", access_token=self.admin_user_tok
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+        # The puppet token should no longer work
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=puppet_token
+        )
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+
+        # .. but the real user's tokens should still work
+        request, channel = self.make_request(
+            "GET", "devices", b"{}", access_token=self.other_user_tok
+        )
+        self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
+
+    @unittest.override_config(
+        {
+            "public_baseurl": "https://example.org/",
+            "user_consent": {
+                "version": "1.0",
+                "policy_name": "My Cool Privacy Policy",
+                "template_dir": "/",
+                "require_at_registration": True,
+                "block_events_error": "You should accept the policy",
+            },
+            "form_secret": "123secret",
+        }
+    )
+    def test_consent(self):
+        """Test that sending a message is not subject to the privacy policies.
+        """
+        # Have the admin user accept the terms.
+        self.get_success(self.store.user_set_consent_version(self.admin_user, "1.0"))
+
+        # First, cheekily accept the terms and create a room
+        self.get_success(self.store.user_set_consent_version(self.other_user, "1.0"))
+        room_id = self.helper.create_room_as(self.other_user, tok=self.other_user_tok)
+        self.helper.send_event(room_id, "com.example.test", tok=self.other_user_tok)
+
+        # Now unaccept it and check that we can't send an event
+        self.get_success(self.store.user_set_consent_version(self.other_user, "0.0"))
+        self.helper.send_event(
+            room_id, "com.example.test", tok=self.other_user_tok, expect_code=403
+        )
+
+        # Login in as the user
+        puppet_token = self._get_token()
+
+        # Sending an event on their behalf should work fine
+        self.helper.send_event(room_id, "com.example.test", tok=puppet_token)
+
+    @override_config(
+        {"limit_usage_by_mau": True, "max_mau_value": 1, "mau_trial_days": 0}
+    )
+    def test_mau_limit(self):
+        # Create a room as the admin user. This will bump the monthly active users to 1.
+        room_id = self.helper.create_room_as(self.admin_user, tok=self.admin_user_tok)
+
+        # Trying to join as the other user should fail due to reaching MAU limit.
+        self.helper.join(
+            room_id, user=self.other_user, tok=self.other_user_tok, expect_code=403
+        )
+
+        # Logging in as the other user and joining a room should work, even
+        # though the MAU limit would stop the user doing so.
+        puppet_token = self._get_token()
+        self.helper.join(room_id, user=self.other_user, tok=puppet_token)
+
+
+class WhoisRestTestCase(unittest.HomeserverTestCase):
+
+    servlets = [
+        synapse.rest.admin.register_servlets,
+        login.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.store = hs.get_datastore()
+
+        self.admin_user = self.register_user("admin", "pass", admin=True)
+        self.admin_user_tok = self.login("admin", "pass")
+
+        self.other_user = self.register_user("user", "pass")
+        self.url1 = "/_synapse/admin/v1/whois/%s" % urllib.parse.quote(self.other_user)
+        self.url2 = "/_matrix/client/r0/admin/whois/%s" % urllib.parse.quote(
+            self.other_user
+        )
+
+    def test_no_auth(self):
+        """
+        Try to get information of an user without authentication.
+        """
+        request, channel = self.make_request("GET", self.url1, b"{}")
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
+        request, channel = self.make_request("GET", self.url2, b"{}")
+        self.assertEqual(401, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
+
+    def test_requester_is_not_admin(self):
+        """
+        If the user is not a server admin, an error is returned.
+        """
+        self.register_user("user2", "pass")
+        other_user2_token = self.login("user2", "pass")
+
+        request, channel = self.make_request(
+            "GET", self.url1, access_token=other_user2_token,
+        )
+        self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
+
+        request, channel = self.make_request(
+            "GET", self.url2, access_token=other_user2_token,
+        )
+        self.assertEqual(403, int(channel.result["code"]), msg=channel.result["body"])
+        self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
+
+    def test_user_is_not_local(self):
+        """
+        Tests that a lookup for a user that is not a local returns a 400
+        """
+        url1 = "/_synapse/admin/v1/whois/@unknown_person:unknown_domain"
+        url2 = "/_matrix/client/r0/admin/whois/@unknown_person:unknown_domain"
+
+        request, channel = self.make_request(
+            "GET", url1, access_token=self.admin_user_tok,
+        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
+        self.assertEqual("Can only whois a local user", channel.json_body["error"])
+
+        request, channel = self.make_request(
+            "GET", url2, access_token=self.admin_user_tok,
+        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
+        self.assertEqual("Can only whois a local user", channel.json_body["error"])
+
+    def test_get_whois_admin(self):
+        """
+        The lookup should succeed for an admin.
+        """
+        request, channel = self.make_request(
+            "GET", self.url1, access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(self.other_user, channel.json_body["user_id"])
+        self.assertIn("devices", channel.json_body)
+
+        request, channel = self.make_request(
+            "GET", self.url2, access_token=self.admin_user_tok,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(self.other_user, channel.json_body["user_id"])
+        self.assertIn("devices", channel.json_body)
+
+    def test_get_whois_user(self):
+        """
+        The lookup should succeed for a normal user looking up their own information.
+        """
+        other_user_token = self.login("user", "pass")
+
+        request, channel = self.make_request(
+            "GET", self.url1, access_token=other_user_token,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(self.other_user, channel.json_body["user_id"])
+        self.assertIn("devices", channel.json_body)
+
+        request, channel = self.make_request(
+            "GET", self.url2, access_token=other_user_token,
+        )
+        self.assertEqual(200, channel.code, msg=channel.json_body)
+        self.assertEqual(self.other_user, channel.json_body["user_id"])
+        self.assertIn("devices", channel.json_body)
diff --git a/tests/rest/client/test_consent.py b/tests/rest/client/test_consent.py
index 6803b372ac..e2e6a5e16d 100644
--- a/tests/rest/client/test_consent.py
+++ b/tests/rest/client/test_consent.py
@@ -21,7 +21,7 @@ from synapse.rest.client.v1 import login, room
 from synapse.rest.consent import consent_resource
 
 from tests import unittest
-from tests.server import render
+from tests.server import FakeSite, make_request
 
 
 class ConsentResourceTestCase(unittest.HomeserverTestCase):
@@ -61,8 +61,9 @@ class ConsentResourceTestCase(unittest.HomeserverTestCase):
     def test_render_public_consent(self):
         """You can observe the terms form without specifying a user"""
         resource = consent_resource.ConsentResource(self.hs)
-        request, channel = self.make_request("GET", "/consent?v=1", shorthand=False)
-        render(request, resource, self.reactor)
+        request, channel = make_request(
+            self.reactor, FakeSite(resource), "GET", "/consent?v=1", shorthand=False
+        )
         self.assertEqual(channel.code, 200)
 
     def test_accept_consent(self):
@@ -81,10 +82,14 @@ class ConsentResourceTestCase(unittest.HomeserverTestCase):
             uri_builder.build_user_consent_uri(user_id).replace("_matrix/", "")
             + "&u=user"
         )
-        request, channel = self.make_request(
-            "GET", consent_uri, access_token=access_token, shorthand=False
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(resource),
+            "GET",
+            consent_uri,
+            access_token=access_token,
+            shorthand=False,
         )
-        render(request, resource, self.reactor)
         self.assertEqual(channel.code, 200)
 
         # Get the version from the body, and whether we've consented
@@ -92,21 +97,26 @@ class ConsentResourceTestCase(unittest.HomeserverTestCase):
         self.assertEqual(consented, "False")
 
         # POST to the consent page, saying we've agreed
-        request, channel = self.make_request(
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(resource),
             "POST",
             consent_uri + "&v=" + version,
             access_token=access_token,
             shorthand=False,
         )
-        render(request, resource, self.reactor)
         self.assertEqual(channel.code, 200)
 
         # Fetch the consent page, to get the consent version -- it should have
         # changed
-        request, channel = self.make_request(
-            "GET", consent_uri, access_token=access_token, shorthand=False
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(resource),
+            "GET",
+            consent_uri,
+            access_token=access_token,
+            shorthand=False,
         )
-        render(request, resource, self.reactor)
         self.assertEqual(channel.code, 200)
 
         # Get the version from the body, and check that it's the version we
diff --git a/tests/rest/client/test_ephemeral_message.py b/tests/rest/client/test_ephemeral_message.py
index 5e9c07ebf3..a1ccc4ee9a 100644
--- a/tests/rest/client/test_ephemeral_message.py
+++ b/tests/rest/client/test_ephemeral_message.py
@@ -94,7 +94,6 @@ class EphemeralMessageTestCase(unittest.HomeserverTestCase):
         url = "/_matrix/client/r0/rooms/%s/event/%s" % (room_id, event_id)
 
         request, channel = self.make_request("GET", url)
-        self.render(request)
 
         self.assertEqual(channel.code, expected_code, channel.result)
 
diff --git a/tests/rest/client/test_identity.py b/tests/rest/client/test_identity.py
index 4224b0a92e..aa094c3543 100644
--- a/tests/rest/client/test_identity.py
+++ b/tests/rest/client/test_identity.py
@@ -53,7 +53,6 @@ class IdentityDisabledTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", "/createRoom", b"{}", access_token=self.tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
         room_id = channel.json_body["room_id"]
 
@@ -67,7 +66,6 @@ class IdentityDisabledTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", request_url, request_data, access_token=self.tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"403", channel.result)
 
     def test_3pid_lookup_disabled(self):
@@ -76,7 +74,6 @@ class IdentityDisabledTestCase(unittest.HomeserverTestCase):
             "?id_server=testis&medium=email&address=foo@bar.baz"
         )
         request, channel = self.make_request("GET", url, access_token=self.tok)
-        self.render(request)
         self.assertEqual(channel.result["code"], b"403", channel.result)
 
     def test_3pid_bulk_lookup_disabled(self):
@@ -89,7 +86,6 @@ class IdentityDisabledTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url, request_data, access_token=self.tok
         )
-        self.render(request)
         self.assertEqual(channel.result["code"], b"403", channel.result)
 
 
@@ -110,8 +106,8 @@ class IdentityEnabledTestCase(unittest.HomeserverTestCase):
         config["trusted_third_party_id_servers"] = ["testis"]
 
         mock_http_client = Mock(spec=["get_json", "post_json_get_json"])
-        mock_http_client.get_json.return_value = defer.succeed((200, "{}"))
-        mock_http_client.post_json_get_json.return_value = defer.succeed((200, "{}"))
+        mock_http_client.get_json.return_value = defer.succeed({"mxid": "@f:test"})
+        mock_http_client.post_json_get_json.return_value = defer.succeed({})
 
         self.hs = self.setup_test_homeserver(
             config=config, simple_http_client=mock_http_client
@@ -120,7 +116,7 @@ class IdentityEnabledTestCase(unittest.HomeserverTestCase):
         # TODO: This class does not use a singleton to get it's http client
         # This should be fixed for easier testing
         # https://github.com/matrix-org/synapse-dinsic/issues/26
-        self.hs.get_handlers().identity_handler.http_client = mock_http_client
+        self.hs.get_identity_handler().http_client = mock_http_client
 
         return self.hs
 
@@ -132,18 +128,9 @@ class IdentityEnabledTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", "/createRoom", b"{}", access_token=self.tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
         room_id = channel.json_body["room_id"]
 
-        # Replace the blacklisting SimpleHttpClient with our mock
-        self.hs.get_room_member_handler().simple_http_client = Mock(
-            spec=["get_json", "post_json_get_json"]
-        )
-        self.hs.get_room_member_handler().simple_http_client.get_json.return_value = defer.succeed(
-            (200, "{}")
-        )
-
         params = {
             "id_server": "testis",
             "medium": "email",
@@ -154,21 +141,20 @@ class IdentityEnabledTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", request_url, request_data, access_token=self.tok
         )
-        self.render(request)
 
-        get_json = self.hs.get_handlers().identity_handler.http_client.get_json
+        get_json = self.hs.get_identity_handler().http_client.get_json
         get_json.assert_called_once_with(
             "https://testis/_matrix/identity/api/v1/lookup",
             {"address": "test@example.com", "medium": "email"},
         )
+        self.assertEquals(channel.result["code"], b"200", channel.result)
 
     def test_3pid_lookup_enabled(self):
         url = (
             "/_matrix/client/unstable/account/3pid/lookup"
             "?id_server=testis&medium=email&address=foo@bar.baz"
         )
-        request, channel = self.make_request("GET", url, access_token=self.tok)
-        self.render(request)
+        self.make_request("GET", url, access_token=self.tok)
 
         get_json = self.hs.get_simple_http_client().get_json
         get_json.assert_called_once_with(
@@ -183,10 +169,7 @@ class IdentityEnabledTestCase(unittest.HomeserverTestCase):
             "threepids": [["email", "foo@bar.baz"], ["email", "john.doe@matrix.org"]],
         }
         request_data = json.dumps(data)
-        request, channel = self.make_request(
-            "POST", url, request_data, access_token=self.tok
-        )
-        self.render(request)
+        self.make_request("POST", url, request_data, access_token=self.tok)
 
         post_json = self.hs.get_simple_http_client().post_json_get_json
         post_json.assert_called_once_with(
diff --git a/tests/rest/client/test_redactions.py b/tests/rest/client/test_redactions.py
index d2bcf256fa..c1f516cc93 100644
--- a/tests/rest/client/test_redactions.py
+++ b/tests/rest/client/test_redactions.py
@@ -72,7 +72,6 @@ class RedactionsTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "POST", path, content={}, access_token=access_token
         )
-        self.render(request)
         self.assertEqual(int(channel.result["code"]), expect_code)
         return channel.json_body
 
@@ -80,7 +79,6 @@ class RedactionsTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "sync", access_token=self.mod_access_token
         )
-        self.render(request)
         self.assertEqual(channel.result["code"], b"200")
         room_sync = channel.json_body["rooms"]["join"][room_id]
         return room_sync["timeline"]["events"]
diff --git a/tests/rest/client/test_retention.py b/tests/rest/client/test_retention.py
index 47c0d5634c..62b41ada42 100644
--- a/tests/rest/client/test_retention.py
+++ b/tests/rest/client/test_retention.py
@@ -328,7 +328,6 @@ class RetentionNoDefaultPolicyTestCase(unittest.HomeserverTestCase):
         url = "/_matrix/client/r0/rooms/%s/event/%s" % (room_id, event_id)
 
         request, channel = self.make_request("GET", url, access_token=self.token)
-        self.render(request)
 
         self.assertEqual(channel.code, expected_code, channel.result)
 
diff --git a/tests/rest/client/test_room_access_rules.py b/tests/rest/client/test_room_access_rules.py
index f233b79de5..f02a613a28 100644
--- a/tests/rest/client/test_room_access_rules.py
+++ b/tests/rest/client/test_room_access_rules.py
@@ -22,6 +22,7 @@ from mock import Mock
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, JoinRules, Membership, RoomCreationPreset
+from synapse.api.errors import SynapseError
 from synapse.rest import admin
 from synapse.rest.client.v1 import directory, login, room
 from synapse.third_party_rules.access_rules import (
@@ -98,9 +99,7 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
         # TODO: This class does not use a singleton to get it's http client
         # This should be fixed for easier testing
         # https://github.com/matrix-org/synapse-dinsic/issues/26
-        self.hs.get_handlers().identity_handler.blacklisting_http_client = (
-            mock_http_client
-        )
+        self.hs.get_identity_handler().blacklisting_http_client = mock_http_client
 
         self.third_party_event_rules = self.hs.get_third_party_event_rules()
 
@@ -279,7 +278,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
             {"visibility": "public"},
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         # List init_state_room_id in the public room list
@@ -289,7 +287,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
             {"visibility": "public"},
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         # Changing access rule to unrestricted should fail.
@@ -364,7 +361,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
         data = {"visibility": "public"}
 
         request, channel = self.make_request("PUT", url, data, access_token=self.tok)
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         # We are allowed to remove the room from the public room list
@@ -372,7 +368,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
         data = {"visibility": "private"}
 
         request, channel = self.make_request("PUT", url, data, access_token=self.tok)
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
     def test_direct(self):
@@ -475,7 +470,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
         data = {"visibility": "public"}
 
         request, channel = self.make_request("PUT", url, data, access_token=self.tok)
-        self.render(request)
         self.assertEqual(channel.code, 403, channel.result)
 
     def test_unrestricted(self):
@@ -555,7 +549,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
         data = {"visibility": "public"}
 
         request, channel = self.make_request("PUT", url, data, access_token=self.tok)
-        self.render(request)
         self.assertEqual(channel.code, 403, channel.result)
 
     def test_change_rules(self):
@@ -614,7 +607,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
         data = {"visibility": "public"}
 
         request, channel = self.make_request("PUT", url, data, access_token=self.tok)
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         # Attempt to switch the room to "unrestricted"
@@ -785,8 +777,8 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
         allowed_requester = create_requester("@user:allowed_domain")
         forbidden_requester = create_requester("@user:forbidden_domain")
 
-        # Create a join event for a forbidden user
-        forbidden_join_event, forbidden_join_event_context = self.get_success(
+        # Assert a join event from a forbidden user to a restricted room is rejected
+        self.get_failure(
             event_creator.create_event(
                 forbidden_requester,
                 {
@@ -796,11 +788,12 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
                     "content": {"membership": Membership.JOIN},
                     "state_key": forbidden_requester.user.to_string(),
                 },
-            )
+            ),
+            SynapseError,
         )
 
-        # Create a join event for an allowed user
-        allowed_join_event, allowed_join_event_context = self.get_success(
+        # A join event from an non-forbidden user to a restricted room is allowed
+        self.get_success(
             event_creator.create_event(
                 allowed_requester,
                 {
@@ -813,26 +806,10 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
             )
         )
 
-        # Assert a join event from a forbidden user to a restricted room is rejected
-        can_join = self.get_success(
-            self.third_party_event_rules.check_event_allowed(
-                forbidden_join_event, forbidden_join_event_context
-            )
-        )
-        self.assertFalse(can_join)
-
-        # But a join event from an non-forbidden user to a restricted room is allowed
-        can_join = self.get_success(
-            self.third_party_event_rules.check_event_allowed(
-                allowed_join_event, allowed_join_event_context
-            )
-        )
-        self.assertTrue(can_join)
-
         # Test that forbidden users can only join unrestricted rooms if they have an invite
 
-        # Recreate the forbidden join event for the unrestricted room instead
-        forbidden_join_event, forbidden_join_event_context = self.get_success(
+        # A forbidden user without an invite should not be able to join an unrestricted room
+        self.get_failure(
             event_creator.create_event(
                 forbidden_requester,
                 {
@@ -842,17 +819,10 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
                     "content": {"membership": Membership.JOIN},
                     "state_key": forbidden_requester.user.to_string(),
                 },
-            )
+            ),
+            SynapseError,
         )
 
-        # A forbidden user without an invite should not be able to join an unrestricted room
-        can_join = self.get_success(
-            self.third_party_event_rules.check_event_allowed(
-                forbidden_join_event, forbidden_join_event_context
-            )
-        )
-        self.assertFalse(can_join)
-
         # However, if we then invite this user...
         self.helper.invite(
             room=self.unrestricted_room,
@@ -863,7 +833,8 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
 
         # And create another join event, making sure that its context states it's coming
         # in after the above invite was made...
-        forbidden_join_event, forbidden_join_event_context = self.get_success(
+        # Then the forbidden user should be able to join!
+        self.get_success(
             event_creator.create_event(
                 forbidden_requester,
                 {
@@ -876,14 +847,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
             )
         )
 
-        # Then the forbidden user should be able to join!
-        can_join = self.get_success(
-            self.third_party_event_rules.check_event_allowed(
-                forbidden_join_event, forbidden_join_event_context
-            )
-        )
-        self.assertTrue(can_join)
-
     def test_freezing_a_room(self):
         """Tests that the power levels in a room change to prevent new events from
         non-admin users when the last admin of a room leaves.
@@ -1040,7 +1003,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", "/_matrix/client/r0/createRoom", content, access_token=self.tok,
         )
-        self.render(request)
 
         self.assertEqual(channel.code, expected_code, channel.result)
 
@@ -1053,7 +1015,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
             "/_matrix/client/r0/rooms/%s/state/%s" % (room_id, ACCESS_RULES_TYPE),
             access_token=self.tok,
         )
-        self.render(request)
 
         self.assertEqual(channel.code, 200, channel.result)
         return channel.json_body["rule"]
@@ -1066,7 +1027,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
             json.dumps(data),
             access_token=self.tok,
         )
-        self.render(request)
 
         self.assertEqual(channel.code, expected_code, channel.result)
 
@@ -1078,7 +1038,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
             json.dumps(data),
             access_token=self.tok,
         )
-        self.render(request)
 
         self.assertEqual(channel.code, expected_code, channel.result)
 
@@ -1091,7 +1050,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
             json.dumps(params),
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, expected_code, channel.result)
 
     def send_state_with_state_key(
@@ -1106,7 +1064,6 @@ class RoomAccessTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", path, json.dumps(body), access_token=tok
         )
-        self.render(request)
 
         self.assertEqual(channel.code, expect_code, channel.result)
 
diff --git a/tests/rest/client/test_shadow_banned.py b/tests/rest/client/test_shadow_banned.py
index dfe4bf7762..94dcfb9f7c 100644
--- a/tests/rest/client/test_shadow_banned.py
+++ b/tests/rest/client/test_shadow_banned.py
@@ -78,7 +78,7 @@ class RoomTestCase(_ShadowBannedBase):
 
     def test_invite_3pid(self):
         """Ensure that a 3PID invite does not attempt to contact the identity server."""
-        identity_handler = self.hs.get_handlers().identity_handler
+        identity_handler = self.hs.get_identity_handler()
         identity_handler.lookup_3pid = Mock(
             side_effect=AssertionError("This should not get called")
         )
@@ -95,7 +95,6 @@ class RoomTestCase(_ShadowBannedBase):
             {"id_server": "test", "medium": "email", "address": "test@test.test"},
             access_token=self.banned_access_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
         # This should have raised an error earlier, but double check this wasn't called.
@@ -110,7 +109,6 @@ class RoomTestCase(_ShadowBannedBase):
             {"visibility": "public", "invite": [self.other_user_id]},
             access_token=self.banned_access_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
         room_id = channel.json_body["room_id"]
 
@@ -166,7 +164,6 @@ class RoomTestCase(_ShadowBannedBase):
             {"new_version": "6"},
             access_token=self.banned_access_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
         # A new room_id should be returned.
         self.assertIn("replacement_room", channel.json_body)
@@ -192,7 +189,6 @@ class RoomTestCase(_ShadowBannedBase):
             {"typing": True, "timeout": 30000},
             access_token=self.banned_access_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         # There should be no typing events.
@@ -208,7 +204,6 @@ class RoomTestCase(_ShadowBannedBase):
             {"typing": True, "timeout": 30000},
             access_token=self.other_access_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         # These appear in the room.
@@ -255,7 +250,6 @@ class ProfileTestCase(_ShadowBannedBase):
             {"displayname": new_display_name},
             access_token=self.banned_access_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
         self.assertEqual(channel.json_body, {})
 
@@ -263,7 +257,6 @@ class ProfileTestCase(_ShadowBannedBase):
         request, channel = self.make_request(
             "GET", "/profile/%s/displayname" % (self.banned_user_id,)
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
         self.assertEqual(channel.json_body["displayname"], new_display_name)
 
@@ -296,7 +289,6 @@ class ProfileTestCase(_ShadowBannedBase):
             {"membership": "join", "displayname": new_display_name},
             access_token=self.banned_access_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
         self.assertIn("event_id", channel.json_body)
 
diff --git a/tests/rest/client/test_third_party_rules.py b/tests/rest/client/test_third_party_rules.py
new file mode 100644
index 0000000000..0e96697f9b
--- /dev/null
+++ b/tests/rest/client/test_third_party_rules.py
@@ -0,0 +1,185 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the 'License');
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an 'AS IS' BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import threading
+from typing import Dict
+
+from mock import Mock
+
+from synapse.events import EventBase
+from synapse.module_api import ModuleApi
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
+from synapse.types import Requester, StateMap
+
+from tests import unittest
+
+thread_local = threading.local()
+
+
+class ThirdPartyRulesTestModule:
+    def __init__(self, config: Dict, module_api: ModuleApi):
+        # keep a record of the "current" rules module, so that the test can patch
+        # it if desired.
+        thread_local.rules_module = self
+        self.module_api = module_api
+
+    async def on_create_room(
+        self, requester: Requester, config: dict, is_requester_admin: bool
+    ):
+        return True
+
+    async def check_event_allowed(self, event: EventBase, state: StateMap[EventBase]):
+        return True
+
+    @staticmethod
+    def parse_config(config):
+        return config
+
+
+def current_rules_module() -> ThirdPartyRulesTestModule:
+    return thread_local.rules_module
+
+
+class ThirdPartyRulesTestCase(unittest.HomeserverTestCase):
+    servlets = [
+        admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+    ]
+
+    def default_config(self):
+        config = super().default_config()
+        config["third_party_event_rules"] = {
+            "module": __name__ + ".ThirdPartyRulesTestModule",
+            "config": {},
+        }
+        return config
+
+    def prepare(self, reactor, clock, homeserver):
+        # Create a user and room to play with during the tests
+        self.user_id = self.register_user("kermit", "monkey")
+        self.tok = self.login("kermit", "monkey")
+
+        self.room_id = self.helper.create_room_as(self.user_id, tok=self.tok)
+
+    def test_third_party_rules(self):
+        """Tests that a forbidden event is forbidden from being sent, but an allowed one
+        can be sent.
+        """
+        # patch the rules module with a Mock which will return False for some event
+        # types
+        async def check(ev, state):
+            return ev.type != "foo.bar.forbidden"
+
+        callback = Mock(spec=[], side_effect=check)
+        current_rules_module().check_event_allowed = callback
+
+        request, channel = self.make_request(
+            "PUT",
+            "/_matrix/client/r0/rooms/%s/send/foo.bar.allowed/1" % self.room_id,
+            {},
+            access_token=self.tok,
+        )
+        self.assertEquals(channel.result["code"], b"200", channel.result)
+
+        callback.assert_called_once()
+
+        # there should be various state events in the state arg: do some basic checks
+        state_arg = callback.call_args[0][1]
+        for k in (("m.room.create", ""), ("m.room.member", self.user_id)):
+            self.assertIn(k, state_arg)
+            ev = state_arg[k]
+            self.assertEqual(ev.type, k[0])
+            self.assertEqual(ev.state_key, k[1])
+
+        request, channel = self.make_request(
+            "PUT",
+            "/_matrix/client/r0/rooms/%s/send/foo.bar.forbidden/2" % self.room_id,
+            {},
+            access_token=self.tok,
+        )
+        self.assertEquals(channel.result["code"], b"403", channel.result)
+
+    def test_cannot_modify_event(self):
+        """cannot accidentally modify an event before it is persisted"""
+
+        # first patch the event checker so that it will try to modify the event
+        async def check(ev: EventBase, state):
+            ev.content = {"x": "y"}
+            return True
+
+        current_rules_module().check_event_allowed = check
+
+        # now send the event
+        request, channel = self.make_request(
+            "PUT",
+            "/_matrix/client/r0/rooms/%s/send/modifyme/1" % self.room_id,
+            {"x": "x"},
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.result["code"], b"500", channel.result)
+
+    def test_modify_event(self):
+        """The module can return a modified version of the event"""
+        # first patch the event checker so that it will modify the event
+        async def check(ev: EventBase, state):
+            d = ev.get_dict()
+            d["content"] = {"x": "y"}
+            return d
+
+        current_rules_module().check_event_allowed = check
+
+        # now send the event
+        request, channel = self.make_request(
+            "PUT",
+            "/_matrix/client/r0/rooms/%s/send/modifyme/1" % self.room_id,
+            {"x": "x"},
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.result["code"], b"200", channel.result)
+        event_id = channel.json_body["event_id"]
+
+        # ... and check that it got modified
+        request, channel = self.make_request(
+            "GET",
+            "/_matrix/client/r0/rooms/%s/event/%s" % (self.room_id, event_id),
+            access_token=self.tok,
+        )
+        self.assertEqual(channel.result["code"], b"200", channel.result)
+        ev = channel.json_body
+        self.assertEqual(ev["content"]["x"], "y")
+
+    def test_send_event(self):
+        """Tests that the module can send an event into a room via the module api"""
+        content = {
+            "msgtype": "m.text",
+            "body": "Hello!",
+        }
+        event_dict = {
+            "room_id": self.room_id,
+            "type": "m.room.message",
+            "content": content,
+            "sender": self.user_id,
+        }
+        event = self.get_success(
+            current_rules_module().module_api.create_and_send_event_into_room(
+                event_dict
+            )
+        )  # type: EventBase
+
+        self.assertEquals(event.sender, self.user_id)
+        self.assertEquals(event.room_id, self.room_id)
+        self.assertEquals(event.type, "m.room.message")
+        self.assertEquals(event.content, content)
diff --git a/tests/rest/client/third_party_rules.py b/tests/rest/client/third_party_rules.py
deleted file mode 100644
index 715e87de08..0000000000
--- a/tests/rest/client/third_party_rules.py
+++ /dev/null
@@ -1,86 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2019 The Matrix.org Foundation C.I.C.
-#
-# Licensed under the Apache License, Version 2.0 (the 'License');
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an 'AS IS' BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-from synapse.rest import admin
-from synapse.rest.client.v1 import login, room
-from synapse.types import Requester
-
-from tests import unittest
-
-
-class ThirdPartyRulesTestModule:
-    def __init__(self, config, *args, **kwargs):
-        pass
-
-    async def on_create_room(
-        self, requester: Requester, config: dict, is_requester_admin: bool
-    ):
-        return True
-
-    async def check_event_allowed(self, event, context):
-        if event.type == "foo.bar.forbidden":
-            return False
-        else:
-            return True
-
-    @staticmethod
-    def parse_config(config):
-        return config
-
-
-class ThirdPartyRulesTestCase(unittest.HomeserverTestCase):
-    servlets = [
-        admin.register_servlets,
-        login.register_servlets,
-        room.register_servlets,
-    ]
-
-    def make_homeserver(self, reactor, clock):
-        config = self.default_config()
-        config["third_party_event_rules"] = {
-            "module": "tests.rest.client.third_party_rules.ThirdPartyRulesTestModule",
-            "config": {},
-        }
-
-        self.hs = self.setup_test_homeserver(config=config)
-        return self.hs
-
-    def prepare(self, reactor, clock, homeserver):
-        # Create a user and room to play with during the tests
-        self.user_id = self.register_user("kermit", "monkey")
-        self.tok = self.login("kermit", "monkey")
-
-        self.room_id = self.helper.create_room_as(self.user_id, tok=self.tok)
-
-    def test_third_party_rules(self):
-        """Tests that a forbidden event is forbidden from being sent, but an allowed one
-        can be sent.
-        """
-        request, channel = self.make_request(
-            "PUT",
-            "/_matrix/client/r0/rooms/%s/send/foo.bar.allowed/1" % self.room_id,
-            {},
-            access_token=self.tok,
-        )
-        self.render(request)
-        self.assertEquals(channel.result["code"], b"200", channel.result)
-
-        request, channel = self.make_request(
-            "PUT",
-            "/_matrix/client/r0/rooms/%s/send/foo.bar.forbidden/1" % self.room_id,
-            {},
-            access_token=self.tok,
-        )
-        self.render(request)
-        self.assertEquals(channel.result["code"], b"403", channel.result)
diff --git a/tests/rest/client/v1/test_directory.py b/tests/rest/client/v1/test_directory.py
index 633b7dbda0..7a2c653df8 100644
--- a/tests/rest/client/v1/test_directory.py
+++ b/tests/rest/client/v1/test_directory.py
@@ -21,6 +21,7 @@ from synapse.types import RoomAlias
 from synapse.util.stringutils import random_string
 
 from tests import unittest
+from tests.unittest import override_config
 
 
 class DirectoryTestCase(unittest.HomeserverTestCase):
@@ -67,10 +68,18 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         self.ensure_user_joined_room()
         self.set_alias_via_directory(400, alias_length=256)
 
-    def test_state_event_in_room(self):
+    @override_config({"default_room_version": 5})
+    def test_state_event_user_in_v5_room(self):
+        """Test that a regular user can add alias events before room v6"""
         self.ensure_user_joined_room()
         self.set_alias_via_state_event(200)
 
+    @override_config({"default_room_version": 6})
+    def test_state_event_v6_room(self):
+        """Test that a regular user can *not* add alias events from room v6"""
+        self.ensure_user_joined_room()
+        self.set_alias_via_state_event(403)
+
     def test_directory_in_room(self):
         self.ensure_user_joined_room()
         self.set_alias_via_directory(200)
@@ -85,7 +94,6 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url, request_data, access_token=self.user_tok
         )
-        self.render(request)
         self.assertEqual(channel.code, 400, channel.result)
 
     def test_room_creation(self):
@@ -99,7 +107,6 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", url, request_data, access_token=self.user_tok
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
     def set_alias_via_state_event(self, expected_code, alias_length=5):
@@ -114,7 +121,6 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", url, request_data, access_token=self.user_tok
         )
-        self.render(request)
         self.assertEqual(channel.code, expected_code, channel.result)
 
     def set_alias_via_directory(self, expected_code, alias_length=5):
@@ -125,7 +131,6 @@ class DirectoryTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", url, request_data, access_token=self.user_tok
         )
-        self.render(request)
         self.assertEqual(channel.code, expected_code, channel.result)
 
     def random_alias(self, length):
diff --git a/tests/rest/client/v1/test_events.py b/tests/rest/client/v1/test_events.py
index f75520877f..12a93f5687 100644
--- a/tests/rest/client/v1/test_events.py
+++ b/tests/rest/client/v1/test_events.py
@@ -42,7 +42,7 @@ class EventStreamPermissionsTestCase(unittest.HomeserverTestCase):
 
         hs = self.setup_test_homeserver(config=config)
 
-        hs.get_handlers().federation_handler = Mock()
+        hs.get_federation_handler = Mock()
 
         return hs
 
@@ -66,14 +66,12 @@ class EventStreamPermissionsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/events?access_token=%s" % ("invalid" + self.token,)
         )
-        self.render(request)
         self.assertEquals(channel.code, 401, msg=channel.result)
 
         # valid token, expect content
         request, channel = self.make_request(
             "GET", "/events?access_token=%s&timeout=0" % (self.token,)
         )
-        self.render(request)
         self.assertEquals(channel.code, 200, msg=channel.result)
         self.assertTrue("chunk" in channel.json_body)
         self.assertTrue("start" in channel.json_body)
@@ -92,7 +90,6 @@ class EventStreamPermissionsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/events?access_token=%s&timeout=0" % (self.token,)
         )
-        self.render(request)
         self.assertEquals(channel.code, 200, msg=channel.result)
 
         # We may get a presence event for ourselves down
@@ -155,5 +152,4 @@ class GetEventsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/events/" + event_id, access_token=self.token,
         )
-        self.render(request)
         self.assertEquals(channel.code, 200, msg=channel.result)
diff --git a/tests/rest/client/v1/test_login.py b/tests/rest/client/v1/test_login.py
index eff17bdf61..ee75f4076f 100644
--- a/tests/rest/client/v1/test_login.py
+++ b/tests/rest/client/v1/test_login.py
@@ -64,7 +64,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
                 "password": "monkey",
             }
             request, channel = self.make_request(b"POST", LOGIN_URL, params)
-            self.render(request)
 
             if i == 5:
                 self.assertEquals(channel.result["code"], b"429", channel.result)
@@ -84,7 +83,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
             "password": "monkey",
         }
         request, channel = self.make_request(b"POST", LOGIN_URL, params)
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
@@ -111,7 +109,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
                 "password": "monkey",
             }
             request, channel = self.make_request(b"POST", LOGIN_URL, params)
-            self.render(request)
 
             if i == 5:
                 self.assertEquals(channel.result["code"], b"429", channel.result)
@@ -131,7 +128,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
             "password": "monkey",
         }
         request, channel = self.make_request(b"POST", LOGIN_URL, params)
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
@@ -158,7 +154,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
                 "password": "notamonkey",
             }
             request, channel = self.make_request(b"POST", LOGIN_URL, params)
-            self.render(request)
 
             if i == 5:
                 self.assertEquals(channel.result["code"], b"429", channel.result)
@@ -178,7 +173,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
             "password": "notamonkey",
         }
         request, channel = self.make_request(b"POST", LOGIN_URL, params)
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"403", channel.result)
 
@@ -188,7 +182,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
 
         # we shouldn't be able to make requests without an access token
         request, channel = self.make_request(b"GET", TEST_URL)
-        self.render(request)
         self.assertEquals(channel.result["code"], b"401", channel.result)
         self.assertEquals(channel.json_body["errcode"], "M_MISSING_TOKEN")
 
@@ -199,7 +192,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
             "password": "monkey",
         }
         request, channel = self.make_request(b"POST", LOGIN_URL, params)
-        self.render(request)
 
         self.assertEquals(channel.code, 200, channel.result)
         access_token = channel.json_body["access_token"]
@@ -209,7 +201,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"GET", TEST_URL, access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.code, 200, channel.result)
 
         # time passes
@@ -219,7 +210,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"GET", TEST_URL, access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.code, 401, channel.result)
         self.assertEquals(channel.json_body["errcode"], "M_UNKNOWN_TOKEN")
         self.assertEquals(channel.json_body["soft_logout"], True)
@@ -236,7 +226,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"GET", TEST_URL, access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.code, 401, channel.result)
         self.assertEquals(channel.json_body["errcode"], "M_UNKNOWN_TOKEN")
         self.assertEquals(channel.json_body["soft_logout"], True)
@@ -247,7 +236,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"GET", TEST_URL, access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.code, 401, channel.result)
         self.assertEquals(channel.json_body["errcode"], "M_UNKNOWN_TOKEN")
         self.assertEquals(channel.json_body["soft_logout"], False)
@@ -257,7 +245,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"DELETE", "devices/" + device_id, access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.code, 401, channel.result)
         # check it's a UI-Auth fail
         self.assertEqual(
@@ -281,7 +268,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
             access_token=access_token,
             content={"auth": auth},
         )
-        self.render(request)
         self.assertEquals(channel.code, 200, channel.result)
 
     @override_config({"session_lifetime": "24h"})
@@ -295,7 +281,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"GET", TEST_URL, access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.code, 200, channel.result)
 
         # time passes
@@ -305,7 +290,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"GET", TEST_URL, access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.code, 401, channel.result)
         self.assertEquals(channel.json_body["errcode"], "M_UNKNOWN_TOKEN")
         self.assertEquals(channel.json_body["soft_logout"], True)
@@ -314,7 +298,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", "/logout", access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
     @override_config({"session_lifetime": "24h"})
@@ -328,7 +311,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"GET", TEST_URL, access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.code, 200, channel.result)
 
         # time passes
@@ -338,7 +320,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"GET", TEST_URL, access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.code, 401, channel.result)
         self.assertEquals(channel.json_body["errcode"], "M_UNKNOWN_TOKEN")
         self.assertEquals(channel.json_body["soft_logout"], True)
@@ -347,7 +328,6 @@ class LoginRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", "/logout/all", access_token=access_token
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
 
@@ -423,7 +403,6 @@ class CASTestCase(unittest.HomeserverTestCase):
 
         # Get Synapse to call the fake CAS and serve the template.
         request, channel = self.make_request("GET", cas_ticket_url)
-        self.render(request)
 
         # Test that the response is HTML.
         self.assertEqual(channel.code, 200)
@@ -468,7 +447,6 @@ class CASTestCase(unittest.HomeserverTestCase):
 
         # Get Synapse to call the fake CAS and serve the template.
         request, channel = self.make_request("GET", cas_ticket_url)
-        self.render(request)
 
         self.assertEqual(channel.code, 302)
         location_headers = channel.headers.getRawHeaders("Location")
@@ -495,7 +473,6 @@ class CASTestCase(unittest.HomeserverTestCase):
 
         # Get Synapse to call the fake CAS and serve the template.
         request, channel = self.make_request("GET", cas_ticket_url)
-        self.render(request)
 
         # Because the user is deactivated they are served an error template.
         self.assertEqual(channel.code, 403)
@@ -530,7 +507,6 @@ class JWTTestCase(unittest.HomeserverTestCase):
             {"type": "org.matrix.login.jwt", "token": self.jwt_encode(*args)}
         )
         request, channel = self.make_request(b"POST", LOGIN_URL, params)
-        self.render(request)
         return channel
 
     def test_login_jwt_valid_registered(self):
@@ -663,7 +639,6 @@ class JWTTestCase(unittest.HomeserverTestCase):
     def test_login_no_token(self):
         params = json.dumps({"type": "org.matrix.login.jwt"})
         request, channel = self.make_request(b"POST", LOGIN_URL, params)
-        self.render(request)
         self.assertEqual(channel.result["code"], b"403", channel.result)
         self.assertEqual(channel.json_body["errcode"], "M_FORBIDDEN")
         self.assertEqual(channel.json_body["error"], "Token field for JWT is missing")
@@ -741,7 +716,6 @@ class JWTPubKeyTestCase(unittest.HomeserverTestCase):
             {"type": "org.matrix.login.jwt", "token": self.jwt_encode(*args)}
         )
         request, channel = self.make_request(b"POST", LOGIN_URL, params)
-        self.render(request)
         return channel
 
     def test_login_jwt_valid(self):
@@ -774,7 +748,6 @@ class AppserviceLoginRestServletTestCase(unittest.HomeserverTestCase):
             "/_matrix/client/r0/register?access_token=%s" % (self.service.token,),
             {"username": username},
         )
-        self.render(request)
 
     def make_homeserver(self, reactor, clock):
         self.hs = self.setup_test_homeserver()
@@ -823,7 +796,6 @@ class AppserviceLoginRestServletTestCase(unittest.HomeserverTestCase):
             b"POST", LOGIN_URL, params, access_token=self.service.token
         )
 
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
     def test_login_appservice_user_bot(self):
@@ -839,7 +811,6 @@ class AppserviceLoginRestServletTestCase(unittest.HomeserverTestCase):
             b"POST", LOGIN_URL, params, access_token=self.service.token
         )
 
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
     def test_login_appservice_wrong_user(self):
@@ -855,7 +826,6 @@ class AppserviceLoginRestServletTestCase(unittest.HomeserverTestCase):
             b"POST", LOGIN_URL, params, access_token=self.service.token
         )
 
-        self.render(request)
         self.assertEquals(channel.result["code"], b"403", channel.result)
 
     def test_login_appservice_wrong_as(self):
@@ -871,7 +841,6 @@ class AppserviceLoginRestServletTestCase(unittest.HomeserverTestCase):
             b"POST", LOGIN_URL, params, access_token=self.another_service.token
         )
 
-        self.render(request)
         self.assertEquals(channel.result["code"], b"403", channel.result)
 
     def test_login_appservice_no_token(self):
@@ -886,5 +855,4 @@ class AppserviceLoginRestServletTestCase(unittest.HomeserverTestCase):
         }
         request, channel = self.make_request(b"POST", LOGIN_URL, params)
 
-        self.render(request)
         self.assertEquals(channel.result["code"], b"401", channel.result)
diff --git a/tests/rest/client/v1/test_presence.py b/tests/rest/client/v1/test_presence.py
index 3c66255dac..5d5c24d01c 100644
--- a/tests/rest/client/v1/test_presence.py
+++ b/tests/rest/client/v1/test_presence.py
@@ -33,12 +33,15 @@ class PresenceTestCase(unittest.HomeserverTestCase):
 
     def make_homeserver(self, reactor, clock):
 
-        hs = self.setup_test_homeserver(
-            "red", http_client=None, federation_client=Mock()
-        )
+        presence_handler = Mock()
+        presence_handler.set_state.return_value = defer.succeed(None)
 
-        hs.presence_handler = Mock()
-        hs.presence_handler.set_state.return_value = defer.succeed(None)
+        hs = self.setup_test_homeserver(
+            "red",
+            http_client=None,
+            federation_client=Mock(),
+            presence_handler=presence_handler,
+        )
 
         return hs
 
@@ -53,10 +56,9 @@ class PresenceTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", "/presence/%s/status" % (self.user_id,), body
         )
-        self.render(request)
 
         self.assertEqual(channel.code, 200)
-        self.assertEqual(self.hs.presence_handler.set_state.call_count, 1)
+        self.assertEqual(self.hs.get_presence_handler().set_state.call_count, 1)
 
     def test_put_presence_disabled(self):
         """
@@ -69,7 +71,6 @@ class PresenceTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", "/presence/%s/status" % (self.user_id,), body
         )
-        self.render(request)
 
         self.assertEqual(channel.code, 200)
-        self.assertEqual(self.hs.presence_handler.set_state.call_count, 0)
+        self.assertEqual(self.hs.get_presence_handler().set_state.call_count, 0)
diff --git a/tests/rest/client/v1/test_profile.py b/tests/rest/client/v1/test_profile.py
index ace0a3c08d..383a9eafac 100644
--- a/tests/rest/client/v1/test_profile.py
+++ b/tests/rest/client/v1/test_profile.py
@@ -195,7 +195,6 @@ class ProfileTestCase(unittest.HomeserverTestCase):
             content=json.dumps({"displayname": "test"}),
             access_token=self.owner_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         res = self.get_displayname()
@@ -209,7 +208,6 @@ class ProfileTestCase(unittest.HomeserverTestCase):
             content=json.dumps({"displayname": "test" * 100}),
             access_token=self.owner_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 400, channel.result)
 
         res = self.get_displayname()
@@ -219,7 +217,6 @@ class ProfileTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/profile/%s/displayname" % (self.owner,)
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
         return channel.json_body["displayname"]
 
@@ -284,7 +281,6 @@ class ProfilesRestrictedTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.profile_url + url_suffix, access_token=access_token
         )
-        self.render(request)
         self.assertEqual(channel.code, expected_code, channel.result)
 
     def ensure_requester_left_room(self):
@@ -327,7 +323,6 @@ class OwnProfileUnrestrictedTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/profile/" + self.requester, access_token=self.requester_tok
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         request, channel = self.make_request(
@@ -335,7 +330,6 @@ class OwnProfileUnrestrictedTestCase(unittest.HomeserverTestCase):
             "/profile/" + self.requester + "/displayname",
             access_token=self.requester_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         request, channel = self.make_request(
@@ -343,5 +337,4 @@ class OwnProfileUnrestrictedTestCase(unittest.HomeserverTestCase):
             "/profile/" + self.requester + "/avatar_url",
             access_token=self.requester_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
diff --git a/tests/rest/client/v1/test_push_rule_attrs.py b/tests/rest/client/v1/test_push_rule_attrs.py
index 081052f6a6..7add5523c8 100644
--- a/tests/rest/client/v1/test_push_rule_attrs.py
+++ b/tests/rest/client/v1/test_push_rule_attrs.py
@@ -48,14 +48,12 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", "/pushrules/global/override/best.friend", body, access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # GET enabled for that new rule
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
         self.assertEqual(channel.json_body["enabled"], True)
 
@@ -79,7 +77,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", "/pushrules/global/override/best.friend", body, access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # disable the rule
@@ -89,14 +86,12 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
             {"enabled": False},
             access_token=token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # check rule disabled
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
         self.assertEqual(channel.json_body["enabled"], False)
 
@@ -104,21 +99,18 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "DELETE", "/pushrules/global/override/best.friend", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # PUT a new rule
         request, channel = self.make_request(
             "PUT", "/pushrules/global/override/best.friend", body, access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # GET enabled for that new rule
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
         self.assertEqual(channel.json_body["enabled"], True)
 
@@ -141,7 +133,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", "/pushrules/global/override/best.friend", body, access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # disable the rule
@@ -151,14 +142,12 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
             {"enabled": False},
             access_token=token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # check rule disabled
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
         self.assertEqual(channel.json_body["enabled"], False)
 
@@ -169,14 +158,12 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
             {"enabled": True},
             access_token=token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # check rule enabled
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
         self.assertEqual(channel.json_body["enabled"], True)
 
@@ -198,7 +185,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
@@ -206,28 +192,24 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", "/pushrules/global/override/best.friend", body, access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # GET enabled for that new rule
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # DELETE the rule
         request, channel = self.make_request(
             "DELETE", "/pushrules/global/override/best.friend", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # check 404 for deleted rule
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
@@ -242,7 +224,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/.m.muahahaha/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
@@ -260,7 +241,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
             {"enabled": True},
             access_token=token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
@@ -278,7 +258,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
             {"enabled": True},
             access_token=token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
@@ -300,14 +279,12 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", "/pushrules/global/override/best.friend", body, access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # GET actions for that new rule
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/actions", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
         self.assertEqual(
             channel.json_body["actions"], ["notify", {"set_tweak": "highlight"}]
@@ -331,7 +308,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", "/pushrules/global/override/best.friend", body, access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # change the rule actions
@@ -341,14 +317,12 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
             {"actions": ["dont_notify"]},
             access_token=token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # GET actions for that new rule
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/actions", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
         self.assertEqual(channel.json_body["actions"], ["dont_notify"])
 
@@ -370,7 +344,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
@@ -378,21 +351,18 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", "/pushrules/global/override/best.friend", body, access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # DELETE the rule
         request, channel = self.make_request(
             "DELETE", "/pushrules/global/override/best.friend", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # check 404 for deleted rule
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/best.friend/enabled", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
@@ -407,7 +377,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/pushrules/global/override/.m.muahahaha/actions", access_token=token
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
@@ -425,7 +394,6 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
             {"actions": ["dont_notify"]},
             access_token=token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
@@ -443,6 +411,5 @@ class PushRuleAttributesTestCase(HomeserverTestCase):
             {"actions": ["dont_notify"]},
             access_token=token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 404)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
diff --git a/tests/rest/client/v1/test_rooms.py b/tests/rest/client/v1/test_rooms.py
index 0d809d25d5..49f1073c88 100644
--- a/tests/rest/client/v1/test_rooms.py
+++ b/tests/rest/client/v1/test_rooms.py
@@ -32,6 +32,7 @@ from synapse.types import JsonDict, RoomAlias, UserID
 from synapse.util.stringutils import random_string
 
 from tests import unittest
+from tests.test_utils import make_awaitable
 
 PATH_PREFIX = b"/_matrix/client/api/v1"
 
@@ -47,7 +48,10 @@ class RoomBase(unittest.HomeserverTestCase):
             "red", http_client=None, federation_client=Mock(),
         )
 
-        self.hs.get_federation_handler = Mock(return_value=Mock())
+        self.hs.get_federation_handler = Mock()
+        self.hs.get_federation_handler.return_value.maybe_backfill = Mock(
+            return_value=make_awaitable(None)
+        )
 
         async def _insert_client_ip(*args, **kwargs):
             return None
@@ -82,7 +86,6 @@ class RoomPermissionsTestCase(RoomBase):
         request, channel = self.make_request(
             "PUT", self.created_rmid_msg_path, b'{"msgtype":"m.text","body":"test msg"}'
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
         # set topic for public room
@@ -91,7 +94,6 @@ class RoomPermissionsTestCase(RoomBase):
             ("rooms/%s/state/m.room.topic" % self.created_public_rmid).encode("ascii"),
             b'{"topic":"Public Room Topic"}',
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
         # auth as user_id now
@@ -114,12 +116,10 @@ class RoomPermissionsTestCase(RoomBase):
             "/rooms/%s/send/m.room.message/mid2" % (self.uncreated_rmid,),
             msg_content,
         )
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
         # send message in created room not joined (no state), expect 403
         request, channel = self.make_request("PUT", send_msg_path(), msg_content)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
         # send message in created room and invited, expect 403
@@ -127,19 +127,16 @@ class RoomPermissionsTestCase(RoomBase):
             room=self.created_rmid, src=self.rmcreator_id, targ=self.user_id
         )
         request, channel = self.make_request("PUT", send_msg_path(), msg_content)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
         # send message in created room and joined, expect 200
         self.helper.join(room=self.created_rmid, user=self.user_id)
         request, channel = self.make_request("PUT", send_msg_path(), msg_content)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         # send message in created room and left, expect 403
         self.helper.leave(room=self.created_rmid, user=self.user_id)
         request, channel = self.make_request("PUT", send_msg_path(), msg_content)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
     def test_topic_perms(self):
@@ -150,20 +147,16 @@ class RoomPermissionsTestCase(RoomBase):
         request, channel = self.make_request(
             "PUT", "/rooms/%s/state/m.room.topic" % self.uncreated_rmid, topic_content
         )
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
         request, channel = self.make_request(
             "GET", "/rooms/%s/state/m.room.topic" % self.uncreated_rmid
         )
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
         # set/get topic in created PRIVATE room not joined, expect 403
         request, channel = self.make_request("PUT", topic_path, topic_content)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
         request, channel = self.make_request("GET", topic_path)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
         # set topic in created PRIVATE room and invited, expect 403
@@ -171,12 +164,10 @@ class RoomPermissionsTestCase(RoomBase):
             room=self.created_rmid, src=self.rmcreator_id, targ=self.user_id
         )
         request, channel = self.make_request("PUT", topic_path, topic_content)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
         # get topic in created PRIVATE room and invited, expect 403
         request, channel = self.make_request("GET", topic_path)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
         # set/get topic in created PRIVATE room and joined, expect 200
@@ -185,29 +176,24 @@ class RoomPermissionsTestCase(RoomBase):
         # Only room ops can set topic by default
         self.helper.auth_user_id = self.rmcreator_id
         request, channel = self.make_request("PUT", topic_path, topic_content)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
         self.helper.auth_user_id = self.user_id
 
         request, channel = self.make_request("GET", topic_path)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
         self.assert_dict(json.loads(topic_content.decode("utf8")), channel.json_body)
 
         # set/get topic in created PRIVATE room and left, expect 403
         self.helper.leave(room=self.created_rmid, user=self.user_id)
         request, channel = self.make_request("PUT", topic_path, topic_content)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
         request, channel = self.make_request("GET", topic_path)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         # get topic in PUBLIC room, not joined, expect 403
         request, channel = self.make_request(
             "GET", "/rooms/%s/state/m.room.topic" % self.created_public_rmid
         )
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
         # set topic in PUBLIC room, not joined, expect 403
@@ -216,14 +202,12 @@ class RoomPermissionsTestCase(RoomBase):
             "/rooms/%s/state/m.room.topic" % self.created_public_rmid,
             topic_content,
         )
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
     def _test_get_membership(self, room=None, members=[], expect_code=None):
         for member in members:
             path = "/rooms/%s/state/m.room.member/%s" % (room, member)
             request, channel = self.make_request("GET", path)
-            self.render(request)
             self.assertEquals(expect_code, channel.code)
 
     def test_membership_basic_room_perms(self):
@@ -396,18 +380,15 @@ class RoomsMemberListTestCase(RoomBase):
     def test_get_member_list(self):
         room_id = self.helper.create_room_as(self.user_id)
         request, channel = self.make_request("GET", "/rooms/%s/members" % room_id)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
     def test_get_member_list_no_room(self):
         request, channel = self.make_request("GET", "/rooms/roomdoesnotexist/members")
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
     def test_get_member_list_no_permission(self):
         room_id = self.helper.create_room_as("@some_other_guy:red")
         request, channel = self.make_request("GET", "/rooms/%s/members" % room_id)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
     def test_get_member_list_mixed_memberships(self):
@@ -417,19 +398,16 @@ class RoomsMemberListTestCase(RoomBase):
         self.helper.invite(room=room_id, src=room_creator, targ=self.user_id)
         # can't see list if you're just invited.
         request, channel = self.make_request("GET", room_path)
-        self.render(request)
         self.assertEquals(403, channel.code, msg=channel.result["body"])
 
         self.helper.join(room=room_id, user=self.user_id)
         # can see list now joined
         request, channel = self.make_request("GET", room_path)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         self.helper.leave(room=room_id, user=self.user_id)
         # can see old list once left
         request, channel = self.make_request("GET", room_path)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
 
@@ -442,7 +420,6 @@ class RoomsCreateTestCase(RoomBase):
         # POST with no config keys, expect new room id
         request, channel = self.make_request("POST", "/createRoom", "{}")
 
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
         self.assertTrue("room_id" in channel.json_body)
 
@@ -451,7 +428,6 @@ class RoomsCreateTestCase(RoomBase):
         request, channel = self.make_request(
             "POST", "/createRoom", b'{"visibility":"private"}'
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         self.assertTrue("room_id" in channel.json_body)
 
@@ -460,7 +436,6 @@ class RoomsCreateTestCase(RoomBase):
         request, channel = self.make_request(
             "POST", "/createRoom", b'{"custom":"stuff"}'
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         self.assertTrue("room_id" in channel.json_body)
 
@@ -469,18 +444,15 @@ class RoomsCreateTestCase(RoomBase):
         request, channel = self.make_request(
             "POST", "/createRoom", b'{"visibility":"private","custom":"things"}'
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         self.assertTrue("room_id" in channel.json_body)
 
     def test_post_room_invalid_content(self):
         # POST with invalid content / paths, expect 400
         request, channel = self.make_request("POST", "/createRoom", b'{"visibili')
-        self.render(request)
         self.assertEquals(400, channel.code)
 
         request, channel = self.make_request("POST", "/createRoom", b'["hello"]')
-        self.render(request)
         self.assertEquals(400, channel.code)
 
     def test_post_room_invitees_invalid_mxid(self):
@@ -489,7 +461,6 @@ class RoomsCreateTestCase(RoomBase):
         request, channel = self.make_request(
             "POST", "/createRoom", b'{"invite":["@alice:example.com "]}'
         )
-        self.render(request)
         self.assertEquals(400, channel.code)
 
 
@@ -506,52 +477,42 @@ class RoomTopicTestCase(RoomBase):
     def test_invalid_puts(self):
         # missing keys or invalid json
         request, channel = self.make_request("PUT", self.path, "{}")
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", self.path, '{"_name":"bo"}')
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", self.path, '{"nao')
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request(
             "PUT", self.path, '[{"_name":"bo"},{"_name":"jill"}]'
         )
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", self.path, "text only")
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", self.path, "")
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         # valid key, wrong type
         content = '{"topic":["Topic name"]}'
         request, channel = self.make_request("PUT", self.path, content)
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
     def test_rooms_topic(self):
         # nothing should be there
         request, channel = self.make_request("GET", self.path)
-        self.render(request)
         self.assertEquals(404, channel.code, msg=channel.result["body"])
 
         # valid put
         content = '{"topic":"Topic name"}'
         request, channel = self.make_request("PUT", self.path, content)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         # valid get
         request, channel = self.make_request("GET", self.path)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
         self.assert_dict(json.loads(content), channel.json_body)
 
@@ -559,12 +520,10 @@ class RoomTopicTestCase(RoomBase):
         # valid put with extra keys
         content = '{"topic":"Seasons","subtopic":"Summer"}'
         request, channel = self.make_request("PUT", self.path, content)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         # valid get
         request, channel = self.make_request("GET", self.path)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
         self.assert_dict(json.loads(content), channel.json_body)
 
@@ -581,29 +540,23 @@ class RoomMemberStateTestCase(RoomBase):
         path = "/rooms/%s/state/m.room.member/%s" % (self.room_id, self.user_id)
         # missing keys or invalid json
         request, channel = self.make_request("PUT", path, "{}")
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", path, '{"_name":"bo"}')
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", path, '{"nao')
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request(
             "PUT", path, b'[{"_name":"bo"},{"_name":"jill"}]'
         )
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", path, "text only")
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", path, "")
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         # valid keys, wrong types
@@ -613,7 +566,6 @@ class RoomMemberStateTestCase(RoomBase):
             Membership.LEAVE,
         )
         request, channel = self.make_request("PUT", path, content.encode("ascii"))
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
     def test_rooms_members_self(self):
@@ -625,11 +577,9 @@ class RoomMemberStateTestCase(RoomBase):
         # valid join message (NOOP since we made the room)
         content = '{"membership":"%s"}' % Membership.JOIN
         request, channel = self.make_request("PUT", path, content.encode("ascii"))
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("GET", path, None)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         expected_response = {"membership": Membership.JOIN}
@@ -645,11 +595,9 @@ class RoomMemberStateTestCase(RoomBase):
         # valid invite message
         content = '{"membership":"%s"}' % Membership.INVITE
         request, channel = self.make_request("PUT", path, content)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("GET", path, None)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
         self.assertEquals(json.loads(content), channel.json_body)
 
@@ -666,11 +614,9 @@ class RoomMemberStateTestCase(RoomBase):
             "Join us!",
         )
         request, channel = self.make_request("PUT", path, content)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("GET", path, None)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
         self.assertEquals(json.loads(content), channel.json_body)
 
@@ -721,7 +667,6 @@ class RoomJoinRatelimitTestCase(RoomBase):
         # Update the display name for the user.
         path = "/_matrix/client/r0/profile/%s/displayname" % self.user_id
         request, channel = self.make_request("PUT", path, {"displayname": "John Doe"})
-        self.render(request)
         self.assertEquals(channel.code, 200, channel.json_body)
 
         # Check that all the rooms have been sent a profile update into.
@@ -732,7 +677,6 @@ class RoomJoinRatelimitTestCase(RoomBase):
             )
 
             request, channel = self.make_request("GET", path)
-            self.render(request)
             self.assertEquals(channel.code, 200)
 
             self.assertIn("displayname", channel.json_body)
@@ -757,7 +701,6 @@ class RoomJoinRatelimitTestCase(RoomBase):
             # if all of these requests ended up joining the user to a room.
             for i in range(4):
                 request, channel = self.make_request("POST", path % room_id, {})
-                self.render(request)
                 self.assertEquals(channel.code, 200)
 
 
@@ -773,29 +716,23 @@ class RoomMessagesTestCase(RoomBase):
         path = "/rooms/%s/send/m.room.message/mid1" % (urlparse.quote(self.room_id))
         # missing keys or invalid json
         request, channel = self.make_request("PUT", path, b"{}")
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", path, b'{"_name":"bo"}')
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", path, b'{"nao')
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request(
             "PUT", path, b'[{"_name":"bo"},{"_name":"jill"}]'
         )
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", path, b"text only")
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         request, channel = self.make_request("PUT", path, b"")
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
     def test_rooms_messages_sent(self):
@@ -803,20 +740,17 @@ class RoomMessagesTestCase(RoomBase):
 
         content = b'{"body":"test","msgtype":{"type":"a"}}'
         request, channel = self.make_request("PUT", path, content)
-        self.render(request)
         self.assertEquals(400, channel.code, msg=channel.result["body"])
 
         # custom message types
         content = b'{"body":"test","msgtype":"test.custom.text"}'
         request, channel = self.make_request("PUT", path, content)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
         # m.text message type
         path = "/rooms/%s/send/m.room.message/mid2" % (urlparse.quote(self.room_id))
         content = b'{"body":"test2","msgtype":"m.text"}'
         request, channel = self.make_request("PUT", path, content)
-        self.render(request)
         self.assertEquals(200, channel.code, msg=channel.result["body"])
 
 
@@ -833,7 +767,6 @@ class RoomInitialSyncTestCase(RoomBase):
         request, channel = self.make_request(
             "GET", "/rooms/%s/initialSync" % self.room_id
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         self.assertEquals(self.room_id, channel.json_body["room_id"])
@@ -877,7 +810,6 @@ class RoomMessageListTestCase(RoomBase):
         request, channel = self.make_request(
             "GET", "/rooms/%s/messages?access_token=x&from=%s" % (self.room_id, token)
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         self.assertTrue("start" in channel.json_body)
         self.assertEquals(token, channel.json_body["start"])
@@ -889,7 +821,6 @@ class RoomMessageListTestCase(RoomBase):
         request, channel = self.make_request(
             "GET", "/rooms/%s/messages?access_token=x&from=%s" % (self.room_id, token)
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         self.assertTrue("start" in channel.json_body)
         self.assertEquals(token, channel.json_body["start"])
@@ -929,7 +860,6 @@ class RoomMessageListTestCase(RoomBase):
                 json.dumps({"types": [EventTypes.Message]}),
             ),
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.json_body)
 
         chunk = channel.json_body["chunk"]
@@ -958,7 +888,6 @@ class RoomMessageListTestCase(RoomBase):
                 json.dumps({"types": [EventTypes.Message]}),
             ),
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.json_body)
 
         chunk = channel.json_body["chunk"]
@@ -976,7 +905,6 @@ class RoomMessageListTestCase(RoomBase):
                 json.dumps({"types": [EventTypes.Message]}),
             ),
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.json_body)
 
         chunk = channel.json_body["chunk"]
@@ -1036,7 +964,6 @@ class RoomSearchTestCase(unittest.HomeserverTestCase):
                 }
             },
         )
-        self.render(request)
 
         # Check we get the results we expect -- one search result, of the sent
         # messages
@@ -1070,7 +997,6 @@ class RoomSearchTestCase(unittest.HomeserverTestCase):
                 }
             },
         )
-        self.render(request)
 
         # Check we get the results we expect -- one search result, of the sent
         # messages
@@ -1107,7 +1033,6 @@ class PublicRoomsRestrictedTestCase(unittest.HomeserverTestCase):
 
     def test_restricted_no_auth(self):
         request, channel = self.make_request("GET", self.url)
-        self.render(request)
         self.assertEqual(channel.code, 401, channel.result)
 
     def test_restricted_auth(self):
@@ -1115,7 +1040,6 @@ class PublicRoomsRestrictedTestCase(unittest.HomeserverTestCase):
         tok = self.login("user", "pass")
 
         request, channel = self.make_request("GET", self.url, access_token=tok)
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
 
@@ -1149,7 +1073,6 @@ class PerRoomProfilesForbiddenTestCase(unittest.HomeserverTestCase):
             request_data,
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         self.room_id = self.helper.create_room_as(self.user_id, tok=self.tok)
@@ -1164,7 +1087,6 @@ class PerRoomProfilesForbiddenTestCase(unittest.HomeserverTestCase):
             request_data,
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
         event_id = channel.json_body["event_id"]
 
@@ -1173,7 +1095,6 @@ class PerRoomProfilesForbiddenTestCase(unittest.HomeserverTestCase):
             "/_matrix/client/r0/rooms/%s/event/%s" % (self.room_id, event_id),
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         res_displayname = channel.json_body["content"]["displayname"]
@@ -1208,7 +1129,6 @@ class RoomMembershipReasonTestCase(unittest.HomeserverTestCase):
             content={"reason": reason},
             access_token=self.second_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         self._check_for_reason(reason)
@@ -1223,7 +1143,6 @@ class RoomMembershipReasonTestCase(unittest.HomeserverTestCase):
             content={"reason": reason},
             access_token=self.second_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         self._check_for_reason(reason)
@@ -1238,7 +1157,6 @@ class RoomMembershipReasonTestCase(unittest.HomeserverTestCase):
             content={"reason": reason, "user_id": self.second_user_id},
             access_token=self.second_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         self._check_for_reason(reason)
@@ -1253,7 +1171,6 @@ class RoomMembershipReasonTestCase(unittest.HomeserverTestCase):
             content={"reason": reason, "user_id": self.second_user_id},
             access_token=self.creator_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         self._check_for_reason(reason)
@@ -1266,7 +1183,6 @@ class RoomMembershipReasonTestCase(unittest.HomeserverTestCase):
             content={"reason": reason, "user_id": self.second_user_id},
             access_token=self.creator_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         self._check_for_reason(reason)
@@ -1279,7 +1195,6 @@ class RoomMembershipReasonTestCase(unittest.HomeserverTestCase):
             content={"reason": reason, "user_id": self.second_user_id},
             access_token=self.creator_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         self._check_for_reason(reason)
@@ -1299,7 +1214,6 @@ class RoomMembershipReasonTestCase(unittest.HomeserverTestCase):
             content={"reason": reason},
             access_token=self.second_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         self._check_for_reason(reason)
@@ -1312,7 +1226,6 @@ class RoomMembershipReasonTestCase(unittest.HomeserverTestCase):
             ),
             access_token=self.creator_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         event_content = channel.json_body
@@ -1361,7 +1274,6 @@ class LabelsTestCase(unittest.HomeserverTestCase):
             % (self.room_id, event_id, json.dumps(self.FILTER_LABELS)),
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         events_before = channel.json_body["events_before"]
@@ -1392,7 +1304,6 @@ class LabelsTestCase(unittest.HomeserverTestCase):
             % (self.room_id, event_id, json.dumps(self.FILTER_NOT_LABELS)),
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         events_before = channel.json_body["events_before"]
@@ -1428,7 +1339,6 @@ class LabelsTestCase(unittest.HomeserverTestCase):
             % (self.room_id, event_id, json.dumps(self.FILTER_LABELS_NOT_LABELS)),
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         events_before = channel.json_body["events_before"]
@@ -1456,7 +1366,6 @@ class LabelsTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/messages?access_token=%s&from=%s&filter=%s"
             % (self.room_id, self.tok, token, json.dumps(self.FILTER_LABELS)),
         )
-        self.render(request)
 
         events = channel.json_body["chunk"]
 
@@ -1474,7 +1383,6 @@ class LabelsTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/messages?access_token=%s&from=%s&filter=%s"
             % (self.room_id, self.tok, token, json.dumps(self.FILTER_NOT_LABELS)),
         )
-        self.render(request)
 
         events = channel.json_body["chunk"]
 
@@ -1503,7 +1411,6 @@ class LabelsTestCase(unittest.HomeserverTestCase):
                 json.dumps(self.FILTER_LABELS_NOT_LABELS),
             ),
         )
-        self.render(request)
 
         events = channel.json_body["chunk"]
 
@@ -1528,7 +1435,6 @@ class LabelsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", "/search?access_token=%s" % self.tok, request_data
         )
-        self.render(request)
 
         results = channel.json_body["search_categories"]["room_events"]["results"]
 
@@ -1564,7 +1470,6 @@ class LabelsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", "/search?access_token=%s" % self.tok, request_data
         )
-        self.render(request)
 
         results = channel.json_body["search_categories"]["room_events"]["results"]
 
@@ -1612,7 +1517,6 @@ class LabelsTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", "/search?access_token=%s" % self.tok, request_data
         )
-        self.render(request)
 
         results = channel.json_body["search_categories"]["room_events"]["results"]
 
@@ -1737,7 +1641,6 @@ class ContextTestCase(unittest.HomeserverTestCase):
             % (self.room_id, event_id),
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         events_before = channel.json_body["events_before"]
@@ -1802,7 +1705,6 @@ class ContextTestCase(unittest.HomeserverTestCase):
             % (self.room_id, event_id),
             access_token=invited_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         events_before = channel.json_body["events_before"]
@@ -1893,7 +1795,6 @@ class RoomAliasListTestCase(unittest.HomeserverTestCase):
             % (self.room_id,),
             access_token=access_token,
         )
-        self.render(request)
         self.assertEqual(channel.code, expected_code, channel.result)
         res = channel.json_body
         self.assertIsInstance(res, dict)
@@ -1912,7 +1813,6 @@ class RoomAliasListTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", url, request_data, access_token=self.room_owner_tok
         )
-        self.render(request)
         self.assertEqual(channel.code, expected_code, channel.result)
 
 
@@ -1943,7 +1843,6 @@ class RoomCanonicalAliasTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "PUT", url, request_data, access_token=self.room_owner_tok
         )
-        self.render(request)
         self.assertEqual(channel.code, expected_code, channel.result)
 
     def _get_canonical_alias(self, expected_code: int = 200) -> JsonDict:
@@ -1953,7 +1852,6 @@ class RoomCanonicalAliasTestCase(unittest.HomeserverTestCase):
             "rooms/%s/state/m.room.canonical_alias" % (self.room_id,),
             access_token=self.room_owner_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, expected_code, channel.result)
         res = channel.json_body
         self.assertIsInstance(res, dict)
@@ -1967,7 +1865,6 @@ class RoomCanonicalAliasTestCase(unittest.HomeserverTestCase):
             json.dumps(content),
             access_token=self.room_owner_tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, expected_code, channel.result)
         res = channel.json_body
         self.assertIsInstance(res, dict)
diff --git a/tests/rest/client/v1/test_typing.py b/tests/rest/client/v1/test_typing.py
index 94d2bf2eb1..bbd30f594b 100644
--- a/tests/rest/client/v1/test_typing.py
+++ b/tests/rest/client/v1/test_typing.py
@@ -44,7 +44,7 @@ class RoomTypingTestCase(unittest.HomeserverTestCase):
 
         self.event_source = hs.get_event_sources().sources["typing"]
 
-        hs.get_handlers().federation_handler = Mock()
+        hs.get_federation_handler = Mock()
 
         async def get_user_by_access_token(token=None, allow_guest=False):
             return {
@@ -99,7 +99,6 @@ class RoomTypingTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/typing/%s" % (self.room_id, self.user_id),
             b'{"typing": true, "timeout": 30000}',
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         self.assertEquals(self.event_source.get_current_key(), 1)
@@ -123,7 +122,6 @@ class RoomTypingTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/typing/%s" % (self.room_id, self.user_id),
             b'{"typing": false}',
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
     def test_typing_timeout(self):
@@ -132,7 +130,6 @@ class RoomTypingTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/typing/%s" % (self.room_id, self.user_id),
             b'{"typing": true, "timeout": 30000}',
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         self.assertEquals(self.event_source.get_current_key(), 1)
@@ -146,7 +143,6 @@ class RoomTypingTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/typing/%s" % (self.room_id, self.user_id),
             b'{"typing": true, "timeout": 30000}',
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         self.assertEquals(self.event_source.get_current_key(), 3)
diff --git a/tests/rest/client/v1/utils.py b/tests/rest/client/v1/utils.py
index afaf9f7b85..737c38c396 100644
--- a/tests/rest/client/v1/utils.py
+++ b/tests/rest/client/v1/utils.py
@@ -23,10 +23,11 @@ from typing import Any, Dict, Optional
 import attr
 
 from twisted.web.resource import Resource
+from twisted.web.server import Site
 
 from synapse.api.constants import Membership
 
-from tests.server import make_request, render
+from tests.server import FakeSite, make_request
 
 
 @attr.s
@@ -36,25 +37,51 @@ class RestHelper:
     """
 
     hs = attr.ib()
-    resource = attr.ib()
+    site = attr.ib(type=Site)
     auth_user_id = attr.ib()
 
     def create_room_as(
-        self, room_creator=None, is_public=True, tok=None, expect_code=200,
-    ):
+        self,
+        room_creator: str = None,
+        is_public: bool = True,
+        room_version: str = None,
+        tok: str = None,
+        expect_code: int = 200,
+    ) -> str:
+        """
+        Create a room.
+
+        Args:
+            room_creator: The user ID to create the room with.
+            is_public: If True, the `visibility` parameter will be set to the
+                default (public). Otherwise, the `visibility` parameter will be set
+                to "private".
+            room_version: The room version to create the room as. Defaults to Synapse's
+                default room version.
+            tok: The access token to use in the request.
+            expect_code: The expected HTTP response code.
+
+        Returns:
+            The ID of the newly created room.
+        """
         temp_id = self.auth_user_id
         self.auth_user_id = room_creator
         path = "/_matrix/client/r0/createRoom"
         content = {}
         if not is_public:
             content["visibility"] = "private"
+        if room_version:
+            content["room_version"] = room_version
         if tok:
             path = path + "?access_token=%s" % tok
 
-        request, channel = make_request(
-            self.hs.get_reactor(), "POST", path, json.dumps(content).encode("utf8")
+        _, channel = make_request(
+            self.hs.get_reactor(),
+            self.site,
+            "POST",
+            path,
+            json.dumps(content).encode("utf8"),
         )
-        render(request, self.resource, self.hs.get_reactor())
 
         assert channel.result["code"] == b"%d" % expect_code, channel.result
         self.auth_user_id = temp_id
@@ -124,12 +151,14 @@ class RestHelper:
         data = {"membership": membership}
         data.update(extra_data)
 
-        request, channel = make_request(
-            self.hs.get_reactor(), "PUT", path, json.dumps(data).encode("utf8")
+        _, channel = make_request(
+            self.hs.get_reactor(),
+            self.site,
+            "PUT",
+            path,
+            json.dumps(data).encode("utf8"),
         )
 
-        render(request, self.resource, self.hs.get_reactor())
-
         assert int(channel.result["code"]) == expect_code, (
             "Expected: %d, got: %d, resp: %r"
             % (expect_code, int(channel.result["code"]), channel.result["body"])
@@ -157,10 +186,13 @@ class RestHelper:
         if tok:
             path = path + "?access_token=%s" % tok
 
-        request, channel = make_request(
-            self.hs.get_reactor(), "PUT", path, json.dumps(content).encode("utf8")
+        _, channel = make_request(
+            self.hs.get_reactor(),
+            self.site,
+            "PUT",
+            path,
+            json.dumps(content).encode("utf8"),
         )
-        render(request, self.resource, self.hs.get_reactor())
 
         assert int(channel.result["code"]) == expect_code, (
             "Expected: %d, got: %d, resp: %r"
@@ -210,9 +242,9 @@ class RestHelper:
         if body is not None:
             content = json.dumps(body).encode("utf8")
 
-        request, channel = make_request(self.hs.get_reactor(), method, path, content)
-
-        render(request, self.resource, self.hs.get_reactor())
+        _, channel = make_request(
+            self.hs.get_reactor(), self.site, method, path, content
+        )
 
         assert int(channel.result["code"]) == expect_code, (
             "Expected: %d, got: %d, resp: %r"
@@ -295,14 +327,15 @@ class RestHelper:
         """
         image_length = len(image_data)
         path = "/_matrix/media/r0/upload?filename=%s" % (filename,)
-        request, channel = make_request(
-            self.hs.get_reactor(), "POST", path, content=image_data, access_token=tok
+        _, channel = make_request(
+            self.hs.get_reactor(),
+            FakeSite(resource),
+            "POST",
+            path,
+            content=image_data,
+            access_token=tok,
+            custom_headers=[(b"Content-Length", str(image_length))],
         )
-        request.requestHeaders.addRawHeader(
-            b"Content-Length", str(image_length).encode("UTF-8")
-        )
-        request.render(resource)
-        self.hs.get_reactor().pump([100])
 
         assert channel.code == expect_code, "Expected: %d, got: %d, resp: %r" % (
             expect_code,
diff --git a/tests/rest/client/v2_alpha/test_account.py b/tests/rest/client/v2_alpha/test_account.py
index ae2cd67f35..2ac1ecb7d3 100644
--- a/tests/rest/client/v2_alpha/test_account.py
+++ b/tests/rest/client/v2_alpha/test_account.py
@@ -31,6 +31,7 @@ from synapse.rest.client.v2_alpha import account, register
 from synapse.rest.synapse.client.password_reset import PasswordResetSubmitTokenResource
 
 from tests import unittest
+from tests.server import FakeSite, make_request
 from tests.unittest import override_config
 
 
@@ -245,7 +246,6 @@ class PasswordResetTestCase(unittest.HomeserverTestCase):
             b"account/password/email/requestToken",
             {"client_secret": client_secret, "email": email, "send_attempt": 1},
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
         return channel.json_body["sid"]
@@ -255,9 +255,14 @@ class PasswordResetTestCase(unittest.HomeserverTestCase):
         path = link.replace("https://example.com", "")
 
         # Load the password reset confirmation page
-        request, channel = self.make_request("GET", path, shorthand=False)
-        request.render(self.submit_token_resource)
-        self.pump()
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(self.submit_token_resource),
+            "GET",
+            path,
+            shorthand=False,
+        )
+
         self.assertEquals(200, channel.code, channel.result)
 
         # Now POST to the same endpoint, mimicking the same behaviour as clicking the
@@ -271,15 +276,15 @@ class PasswordResetTestCase(unittest.HomeserverTestCase):
                 form_args.append(arg)
 
         # Confirm the password reset
-        request, channel = self.make_request(
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(self.submit_token_resource),
             "POST",
             path,
             content=urlencode(form_args).encode("utf8"),
             shorthand=False,
             content_is_form=True,
         )
-        request.render(self.submit_token_resource)
-        self.pump()
         self.assertEquals(200, channel.code, channel.result)
 
     def _get_link_from_email(self):
@@ -319,7 +324,6 @@ class PasswordResetTestCase(unittest.HomeserverTestCase):
                 },
             },
         )
-        self.render(request)
         self.assertEquals(expected_code, channel.code, channel.result)
 
 
@@ -349,10 +353,8 @@ class DeactivateTestCase(unittest.HomeserverTestCase):
 
         # Check that this access token has been invalidated.
         request, channel = self.make_request("GET", "account/whoami")
-        self.render(request)
         self.assertEqual(request.code, 401)
 
-    @unittest.INFO
     def test_pending_invites(self):
         """Tests that deactivating a user rejects every pending invite for them."""
         store = self.hs.get_datastore()
@@ -408,7 +410,6 @@ class DeactivateTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", "account/deactivate", request_data, access_token=tok
         )
-        self.render(request)
         self.assertEqual(request.code, 200)
 
 
@@ -543,7 +544,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
             },
             access_token=self.user_id_tok,
         )
-        self.render(request)
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
@@ -551,7 +551,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url_3pid, access_token=self.user_id_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertFalse(channel.json_body["threepids"])
@@ -576,14 +575,12 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
             {"medium": "email", "address": self.email},
             access_token=self.user_id_tok,
         )
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Get user
         request, channel = self.make_request(
             "GET", self.url_3pid, access_token=self.user_id_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertFalse(channel.json_body["threepids"])
@@ -610,7 +607,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
             {"medium": "email", "address": self.email},
             access_token=self.user_id_tok,
         )
-        self.render(request)
 
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
@@ -619,7 +615,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url_3pid, access_token=self.user_id_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("email", channel.json_body["threepids"][0]["medium"])
@@ -648,7 +643,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
             },
             access_token=self.user_id_tok,
         )
-        self.render(request)
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.THREEPID_AUTH_FAILED, channel.json_body["errcode"])
 
@@ -656,7 +650,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url_3pid, access_token=self.user_id_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertFalse(channel.json_body["threepids"])
@@ -683,7 +676,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
             },
             access_token=self.user_id_tok,
         )
-        self.render(request)
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(Codes.THREEPID_AUTH_FAILED, channel.json_body["errcode"])
 
@@ -691,7 +683,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url_3pid, access_token=self.user_id_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertFalse(channel.json_body["threepids"])
@@ -796,7 +787,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", b"account/3pid/email/requestToken", body,
         )
-        self.render(request)
         self.assertEquals(expect_code, channel.code, channel.result)
 
         return channel.json_body.get("sid")
@@ -809,7 +799,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
             b"account/3pid/email/requestToken",
             {"client_secret": client_secret, "email": email, "send_attempt": 1},
         )
-        self.render(request)
         self.assertEqual(400, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual(expected_errcode, channel.json_body["errcode"])
         self.assertEqual(expected_error, channel.json_body["error"])
@@ -819,7 +808,6 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
         path = link.replace("https://example.com", "")
 
         request, channel = self.make_request("GET", path, shorthand=False)
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
     def _get_link_from_email(self):
@@ -868,14 +856,12 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
             access_token=self.user_id_tok,
         )
 
-        self.render(request)
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
 
         # Get user
         request, channel = self.make_request(
             "GET", self.url_3pid, access_token=self.user_id_tok,
         )
-        self.render(request)
 
         self.assertEqual(200, int(channel.result["code"]), msg=channel.result["body"])
         self.assertEqual("email", channel.json_body["threepids"][0]["medium"])
diff --git a/tests/rest/client/v2_alpha/test_auth.py b/tests/rest/client/v2_alpha/test_auth.py
index 293ccfba2b..77246e478f 100644
--- a/tests/rest/client/v2_alpha/test_auth.py
+++ b/tests/rest/client/v2_alpha/test_auth.py
@@ -38,11 +38,6 @@ class DummyRecaptchaChecker(UserInteractiveAuthChecker):
         return succeed(True)
 
 
-class DummyPasswordChecker(UserInteractiveAuthChecker):
-    def check_auth(self, authdict, clientip):
-        return succeed(authdict["identifier"]["user"])
-
-
 class FallbackAuthTests(unittest.HomeserverTestCase):
 
     servlets = [
@@ -72,7 +67,6 @@ class FallbackAuthTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", "register", body
         )  # type: SynapseRequest, FakeChannel
-        self.render(request)
 
         self.assertEqual(request.code, expected_response)
         return channel
@@ -87,7 +81,6 @@ class FallbackAuthTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "auth/m.login.recaptcha/fallback/web?session=" + session
         )  # type: SynapseRequest, FakeChannel
-        self.render(request)
         self.assertEqual(request.code, 200)
 
         request, channel = self.make_request(
@@ -96,7 +89,6 @@ class FallbackAuthTests(unittest.HomeserverTestCase):
             + post_session
             + "&g-recaptcha-response=a",
         )
-        self.render(request)
         self.assertEqual(request.code, expected_post_response)
 
         # The recaptcha handler is called with the response given
@@ -104,7 +96,6 @@ class FallbackAuthTests(unittest.HomeserverTestCase):
         self.assertEqual(len(attempts), 1)
         self.assertEqual(attempts[0][0]["response"], "a")
 
-    @unittest.INFO
     def test_fallback_captcha(self):
         """Ensure that fallback auth via a captcha works."""
         # Returns a 401 as per the spec
@@ -166,9 +157,6 @@ class UIAuthTests(unittest.HomeserverTestCase):
     ]
 
     def prepare(self, reactor, clock, hs):
-        auth_handler = hs.get_auth_handler()
-        auth_handler.checkers[LoginType.PASSWORD] = DummyPasswordChecker(hs)
-
         self.user_pass = "pass"
         self.user = self.register_user("test", self.user_pass)
         self.user_tok = self.login("test", self.user_pass)
@@ -178,7 +166,6 @@ class UIAuthTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "devices", access_token=self.user_tok,
         )  # type: SynapseRequest, FakeChannel
-        self.render(request)
 
         # Get the ID of the device.
         self.assertEqual(request.code, 200)
@@ -191,7 +178,6 @@ class UIAuthTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "DELETE", "devices/" + device, body, access_token=self.user_tok
         )  # type: SynapseRequest, FakeChannel
-        self.render(request)
 
         # Ensure the response is sane.
         self.assertEqual(request.code, expected_response)
@@ -205,7 +191,6 @@ class UIAuthTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", "delete_devices", body, access_token=self.user_tok,
         )  # type: SynapseRequest, FakeChannel
-        self.render(request)
 
         # Ensure the response is sane.
         self.assertEqual(request.code, expected_response)
@@ -241,6 +226,31 @@ class UIAuthTests(unittest.HomeserverTestCase):
             },
         )
 
+    def test_grandfathered_identifier(self):
+        """Check behaviour without "identifier" dict
+
+        Synapse used to require clients to submit a "user" field for m.login.password
+        UIA - check that still works.
+        """
+
+        device_id = self.get_device_ids()[0]
+        channel = self.delete_device(device_id, 401)
+        session = channel.json_body["session"]
+
+        # Make another request providing the UI auth flow.
+        self.delete_device(
+            device_id,
+            200,
+            {
+                "auth": {
+                    "type": "m.login.password",
+                    "user": self.user,
+                    "password": self.user_pass,
+                    "session": session,
+                },
+            },
+        )
+
     def test_can_change_body(self):
         """
         The client dict can be modified during the user interactive authentication session.
diff --git a/tests/rest/client/v2_alpha/test_capabilities.py b/tests/rest/client/v2_alpha/test_capabilities.py
index b9e01c9418..767e126875 100644
--- a/tests/rest/client/v2_alpha/test_capabilities.py
+++ b/tests/rest/client/v2_alpha/test_capabilities.py
@@ -37,7 +37,6 @@ class CapabilitiesTestCase(unittest.HomeserverTestCase):
 
     def test_check_auth_required(self):
         request, channel = self.make_request("GET", self.url)
-        self.render(request)
 
         self.assertEqual(channel.code, 401)
 
@@ -46,7 +45,6 @@ class CapabilitiesTestCase(unittest.HomeserverTestCase):
         access_token = self.login("user", "pass")
 
         request, channel = self.make_request("GET", self.url, access_token=access_token)
-        self.render(request)
         capabilities = channel.json_body["capabilities"]
 
         self.assertEqual(channel.code, 200)
@@ -65,7 +63,6 @@ class CapabilitiesTestCase(unittest.HomeserverTestCase):
         access_token = self.login(user, password)
 
         request, channel = self.make_request("GET", self.url, access_token=access_token)
-        self.render(request)
         capabilities = channel.json_body["capabilities"]
 
         self.assertEqual(channel.code, 200)
@@ -74,7 +71,6 @@ class CapabilitiesTestCase(unittest.HomeserverTestCase):
         self.assertTrue(capabilities["m.change_password"]["enabled"])
         self.get_success(self.store.user_set_password_hash(user, None))
         request, channel = self.make_request("GET", self.url, access_token=access_token)
-        self.render(request)
         capabilities = channel.json_body["capabilities"]
 
         self.assertEqual(channel.code, 200)
diff --git a/tests/rest/client/v2_alpha/test_filter.py b/tests/rest/client/v2_alpha/test_filter.py
index de00350580..231d5aefea 100644
--- a/tests/rest/client/v2_alpha/test_filter.py
+++ b/tests/rest/client/v2_alpha/test_filter.py
@@ -41,7 +41,6 @@ class FilterTestCase(unittest.HomeserverTestCase):
             "/_matrix/client/r0/user/%s/filter" % (self.user_id),
             self.EXAMPLE_FILTER_JSON,
         )
-        self.render(request)
 
         self.assertEqual(channel.result["code"], b"200")
         self.assertEqual(channel.json_body, {"filter_id": "0"})
@@ -55,7 +54,6 @@ class FilterTestCase(unittest.HomeserverTestCase):
             "/_matrix/client/r0/user/%s/filter" % ("@watermelon:test"),
             self.EXAMPLE_FILTER_JSON,
         )
-        self.render(request)
 
         self.assertEqual(channel.result["code"], b"403")
         self.assertEquals(channel.json_body["errcode"], Codes.FORBIDDEN)
@@ -68,7 +66,6 @@ class FilterTestCase(unittest.HomeserverTestCase):
             "/_matrix/client/r0/user/%s/filter" % (self.user_id),
             self.EXAMPLE_FILTER_JSON,
         )
-        self.render(request)
 
         self.hs.is_mine = _is_mine
         self.assertEqual(channel.result["code"], b"403")
@@ -85,7 +82,6 @@ class FilterTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/user/%s/filter/%s" % (self.user_id, filter_id)
         )
-        self.render(request)
 
         self.assertEqual(channel.result["code"], b"200")
         self.assertEquals(channel.json_body, self.EXAMPLE_FILTER)
@@ -94,7 +90,6 @@ class FilterTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/user/%s/filter/12382148321" % (self.user_id)
         )
-        self.render(request)
 
         self.assertEqual(channel.result["code"], b"404")
         self.assertEquals(channel.json_body["errcode"], Codes.NOT_FOUND)
@@ -105,7 +100,6 @@ class FilterTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/user/%s/filter/foobar" % (self.user_id)
         )
-        self.render(request)
 
         self.assertEqual(channel.result["code"], b"400")
 
@@ -114,6 +108,5 @@ class FilterTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/user/%s/filter/" % (self.user_id)
         )
-        self.render(request)
 
         self.assertEqual(channel.result["code"], b"400")
diff --git a/tests/rest/client/v2_alpha/test_password_policy.py b/tests/rest/client/v2_alpha/test_password_policy.py
index c57072f50c..ee86b94917 100644
--- a/tests/rest/client/v2_alpha/test_password_policy.py
+++ b/tests/rest/client/v2_alpha/test_password_policy.py
@@ -73,7 +73,6 @@ class PasswordPolicyTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/password_policy"
         )
-        self.render(request)
 
         self.assertEqual(channel.code, 200, channel.result)
         self.assertEqual(
@@ -91,7 +90,6 @@ class PasswordPolicyTestCase(unittest.HomeserverTestCase):
     def test_password_too_short(self):
         request_data = json.dumps({"username": "kermit", "password": "shorty"})
         request, channel = self.make_request("POST", self.register_url, request_data)
-        self.render(request)
 
         self.assertEqual(channel.code, 400, channel.result)
         self.assertEqual(
@@ -101,7 +99,6 @@ class PasswordPolicyTestCase(unittest.HomeserverTestCase):
     def test_password_no_digit(self):
         request_data = json.dumps({"username": "kermit", "password": "longerpassword"})
         request, channel = self.make_request("POST", self.register_url, request_data)
-        self.render(request)
 
         self.assertEqual(channel.code, 400, channel.result)
         self.assertEqual(
@@ -111,7 +108,6 @@ class PasswordPolicyTestCase(unittest.HomeserverTestCase):
     def test_password_no_symbol(self):
         request_data = json.dumps({"username": "kermit", "password": "l0ngerpassword"})
         request, channel = self.make_request("POST", self.register_url, request_data)
-        self.render(request)
 
         self.assertEqual(channel.code, 400, channel.result)
         self.assertEqual(
@@ -121,7 +117,6 @@ class PasswordPolicyTestCase(unittest.HomeserverTestCase):
     def test_password_no_uppercase(self):
         request_data = json.dumps({"username": "kermit", "password": "l0ngerpassword!"})
         request, channel = self.make_request("POST", self.register_url, request_data)
-        self.render(request)
 
         self.assertEqual(channel.code, 400, channel.result)
         self.assertEqual(
@@ -131,7 +126,6 @@ class PasswordPolicyTestCase(unittest.HomeserverTestCase):
     def test_password_no_lowercase(self):
         request_data = json.dumps({"username": "kermit", "password": "L0NGERPASSWORD!"})
         request, channel = self.make_request("POST", self.register_url, request_data)
-        self.render(request)
 
         self.assertEqual(channel.code, 400, channel.result)
         self.assertEqual(
@@ -141,7 +135,6 @@ class PasswordPolicyTestCase(unittest.HomeserverTestCase):
     def test_password_compliant(self):
         request_data = json.dumps({"username": "kermit", "password": "L0ngerpassword!"})
         request, channel = self.make_request("POST", self.register_url, request_data)
-        self.render(request)
 
         # Getting a 401 here means the password has passed validation and the server has
         # responded with a list of registration flows.
@@ -173,7 +166,6 @@ class PasswordPolicyTestCase(unittest.HomeserverTestCase):
             request_data,
             access_token=tok,
         )
-        self.render(request)
 
         self.assertEqual(channel.code, 400, channel.result)
         self.assertEqual(channel.json_body["errcode"], Codes.PASSWORD_NO_DIGIT)
diff --git a/tests/rest/client/v2_alpha/test_register.py b/tests/rest/client/v2_alpha/test_register.py
index 46d0374ca4..b53b47a0cc 100644
--- a/tests/rest/client/v2_alpha/test_register.py
+++ b/tests/rest/client/v2_alpha/test_register.py
@@ -59,6 +59,7 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
             self.hs.config.server_name,
             id="1234",
             namespaces={"users": [{"regex": r"@as_user.*", "exclusive": True}]},
+            sender="@as:test",
         )
 
         self.hs.get_datastore().services_cache.append(appservice)
@@ -67,7 +68,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", self.url + b"?access_token=i_am_an_app_service", request_data
         )
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"200", channel.result)
         det_data = {"user_id": user_id, "home_server": self.hs.hostname}
@@ -79,14 +79,12 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", self.url + b"?access_token=i_am_an_app_service", request_data
         )
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"401", channel.result)
 
     def test_POST_bad_password(self):
         request_data = json.dumps({"username": "kermit", "password": 666})
         request, channel = self.make_request(b"POST", self.url, request_data)
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"400", channel.result)
         self.assertEquals(channel.json_body["error"], "Invalid password")
@@ -102,7 +100,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
         }
         request_data = json.dumps(params)
         request, channel = self.make_request(b"POST", self.url, request_data)
-        self.render(request)
 
         det_data = {
             "user_id": user_id,
@@ -118,7 +115,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
         self.auth_result = (None, {"username": "kermit", "password": "monkey"}, None)
 
         request, channel = self.make_request(b"POST", self.url, request_data)
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"403", channel.result)
         self.assertEquals(channel.json_body["error"], "Registration has been disabled")
@@ -128,7 +124,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
         self.hs.config.allow_guest_access = True
 
         request, channel = self.make_request(b"POST", self.url + b"?kind=guest", b"{}")
-        self.render(request)
 
         det_data = {"home_server": self.hs.hostname, "device_id": "guest_device"}
         self.assertEquals(channel.result["code"], b"200", channel.result)
@@ -138,7 +133,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
         self.hs.config.allow_guest_access = False
 
         request, channel = self.make_request(b"POST", self.url + b"?kind=guest", b"{}")
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"403", channel.result)
         self.assertEquals(channel.json_body["error"], "Guest access is disabled")
@@ -148,7 +142,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
         for i in range(0, 6):
             url = self.url + b"?kind=guest"
             request, channel = self.make_request(b"POST", url, b"{}")
-            self.render(request)
 
             if i == 5:
                 self.assertEquals(channel.result["code"], b"429", channel.result)
@@ -159,7 +152,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
         self.reactor.advance(retry_after_ms / 1000.0 + 1.0)
 
         request, channel = self.make_request(b"POST", self.url + b"?kind=guest", b"{}")
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
@@ -174,7 +166,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
             }
             request_data = json.dumps(params)
             request, channel = self.make_request(b"POST", self.url, request_data)
-            self.render(request)
 
             if i == 5:
                 self.assertEquals(channel.result["code"], b"429", channel.result)
@@ -185,13 +176,11 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
         self.reactor.advance(retry_after_ms / 1000.0 + 1.0)
 
         request, channel = self.make_request(b"POST", self.url + b"?kind=guest", b"{}")
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
     def test_advertised_flows(self):
         request, channel = self.make_request(b"POST", self.url, b"{}")
-        self.render(request)
         self.assertEquals(channel.result["code"], b"401", channel.result)
         flows = channel.json_body["flows"]
 
@@ -215,7 +204,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
     )
     def test_advertised_flows_captcha_and_terms_and_3pids(self):
         request, channel = self.make_request(b"POST", self.url, b"{}")
-        self.render(request)
         self.assertEquals(channel.result["code"], b"401", channel.result)
         flows = channel.json_body["flows"]
 
@@ -248,7 +236,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
     )
     def test_advertised_flows_no_msisdn_email_required(self):
         request, channel = self.make_request(b"POST", self.url, b"{}")
-        self.render(request)
         self.assertEquals(channel.result["code"], b"401", channel.result)
         flows = channel.json_body["flows"]
 
@@ -293,7 +280,6 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
             b"register/email/requestToken",
             {"client_secret": "foobar", "email": email, "send_attempt": 1},
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.result)
 
         self.assertIsNotNone(channel.json_body.get("sid"))
@@ -371,14 +357,12 @@ class AccountValidityTestCase(unittest.HomeserverTestCase):
         # The specific endpoint doesn't matter, all we need is an authenticated
         # endpoint.
         request, channel = self.make_request(b"GET", "/sync", access_token=tok)
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         self.reactor.advance(datetime.timedelta(weeks=1).total_seconds())
 
         request, channel = self.make_request(b"GET", "/sync", access_token=tok)
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"403", channel.result)
         self.assertEquals(
@@ -397,19 +381,17 @@ class AccountValidityTestCase(unittest.HomeserverTestCase):
         self.register_user("admin", "adminpassword", admin=True)
         admin_tok = self.login("admin", "adminpassword")
 
-        url = "/_matrix/client/unstable/admin/account_validity/validity"
+        url = "/_synapse/admin/v1/account_validity/validity"
         params = {"user_id": user_id}
         request_data = json.dumps(params)
         request, channel = self.make_request(
             b"POST", url, request_data, access_token=admin_tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         # The specific endpoint doesn't matter, all we need is an authenticated
         # endpoint.
         request, channel = self.make_request(b"GET", "/sync", access_token=tok)
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
     def test_manual_expire(self):
@@ -419,7 +401,7 @@ class AccountValidityTestCase(unittest.HomeserverTestCase):
         self.register_user("admin", "adminpassword", admin=True)
         admin_tok = self.login("admin", "adminpassword")
 
-        url = "/_matrix/client/unstable/admin/account_validity/validity"
+        url = "/_synapse/admin/v1/account_validity/validity"
         params = {
             "user_id": user_id,
             "expiration_ts": 0,
@@ -429,13 +411,11 @@ class AccountValidityTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", url, request_data, access_token=admin_tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         # The specific endpoint doesn't matter, all we need is an authenticated
         # endpoint.
         request, channel = self.make_request(b"GET", "/sync", access_token=tok)
-        self.render(request)
         self.assertEquals(channel.result["code"], b"403", channel.result)
         self.assertEquals(
             channel.json_body["errcode"], Codes.EXPIRED_ACCOUNT, channel.result
@@ -448,7 +428,7 @@ class AccountValidityTestCase(unittest.HomeserverTestCase):
         self.register_user("admin", "adminpassword", admin=True)
         admin_tok = self.login("admin", "adminpassword")
 
-        url = "/_matrix/client/unstable/admin/account_validity/validity"
+        url = "/_synapse/admin/v1/account_validity/validity"
         params = {
             "user_id": user_id,
             "expiration_ts": 0,
@@ -458,12 +438,10 @@ class AccountValidityTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", url, request_data, access_token=admin_tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         # Try to log the user out
         request, channel = self.make_request(b"POST", "/logout", access_token=tok)
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         # Log the user in again (allowed for expired accounts)
@@ -471,7 +449,6 @@ class AccountValidityTestCase(unittest.HomeserverTestCase):
 
         # Try to log out all of the user's sessions
         request, channel = self.make_request(b"POST", "/logout/all", access_token=tok)
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
 
@@ -515,7 +492,7 @@ class AccountValidityUserDirectoryTestCase(unittest.HomeserverTestCase):
         admin_tok = self.login("admin", "adminpassword")
 
         # Ensure the admin never expires
-        url = "/_matrix/client/unstable/admin/account_validity/validity"
+        url = "/_synapse/admin/v1/account_validity/validity"
         params = {
             "user_id": admin_id,
             "expiration_ts": 999999999999,
@@ -525,7 +502,6 @@ class AccountValidityUserDirectoryTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", url, request_data, access_token=admin_tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         # Mock the homeserver's HTTP client
@@ -556,7 +532,7 @@ class AccountValidityUserDirectoryTestCase(unittest.HomeserverTestCase):
         self.assertIsNotNone(replicated_content)
 
         # Expire the user
-        url = "/_matrix/client/unstable/admin/account_validity/validity"
+        url = "/_synapse/admin/v1/account_validity/validity"
         params = {
             "user_id": user_id,
             "expiration_ts": 0,
@@ -566,7 +542,6 @@ class AccountValidityUserDirectoryTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", url, request_data, access_token=admin_tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         # Wait for the background job to run which hides expired users in the directory
@@ -590,7 +565,7 @@ class AccountValidityUserDirectoryTestCase(unittest.HomeserverTestCase):
         self.assertIsNone(replicated_content)
 
         # Now renew the user, and check they get replicated again to the identity server
-        url = "/_matrix/client/unstable/admin/account_validity/validity"
+        url = "/_synapse/admin/v1/account_validity/validity"
         params = {
             "user_id": user_id,
             "expiration_ts": 99999999999,
@@ -600,7 +575,6 @@ class AccountValidityUserDirectoryTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             b"POST", url, request_data, access_token=admin_tok
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         self.pump(10)
@@ -695,7 +669,6 @@ class AccountValidityRenewalByEmailTestCase(unittest.HomeserverTestCase):
         renewal_token = self.get_success(self.store.get_renewal_token_for_user(user_id))
         url = "/_matrix/client/unstable/account_validity/renew?token=%s" % renewal_token
         request, channel = self.make_request(b"GET", url)
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         # Check that we're getting HTML back.
@@ -714,7 +687,6 @@ class AccountValidityRenewalByEmailTestCase(unittest.HomeserverTestCase):
         # Move 1 day forward. Try to renew with the same token again.
         url = "/_matrix/client/unstable/account_validity/renew?token=%s" % renewal_token
         request, channel = self.make_request(b"GET", url)
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         # Check that we're getting HTML back.
@@ -735,7 +707,6 @@ class AccountValidityRenewalByEmailTestCase(unittest.HomeserverTestCase):
         # succeed.
         self.reactor.advance(datetime.timedelta(days=3).total_seconds())
         request, channel = self.make_request(b"GET", "/sync", access_token=tok)
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
     def test_renewal_invalid_token(self):
@@ -743,7 +714,6 @@ class AccountValidityRenewalByEmailTestCase(unittest.HomeserverTestCase):
         # expected, i.e. that it responds with 404 Not Found and the correct HTML.
         url = "/_matrix/client/unstable/account_validity/renew?token=123"
         request, channel = self.make_request(b"GET", url)
-        self.render(request)
         self.assertEquals(channel.result["code"], b"404", channel.result)
 
         # Check that we're getting HTML back.
@@ -766,7 +736,6 @@ class AccountValidityRenewalByEmailTestCase(unittest.HomeserverTestCase):
             "/_matrix/client/unstable/account_validity/send_mail",
             access_token=tok,
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         self.assertEqual(len(self.email_attempts), 1)
@@ -789,8 +758,7 @@ class AccountValidityRenewalByEmailTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "POST", "account/deactivate", request_data, access_token=tok
         )
-        self.render(request)
-        self.assertEqual(request.code, 200, channel.result)
+        self.assertEqual(request.code, 200)
 
         self.reactor.advance(datetime.timedelta(days=8).total_seconds())
 
@@ -801,7 +769,7 @@ class AccountValidityRenewalByEmailTestCase(unittest.HomeserverTestCase):
         tok = self.login("kermit", "monkey")
         # We need to manually add an email address otherwise the handler will do
         # nothing.
-        now = self.hs.clock.time_msec()
+        now = self.hs.get_clock().time_msec()
         self.get_success(
             self.store.user_add_threepid(
                 user_id=user_id,
@@ -819,7 +787,7 @@ class AccountValidityRenewalByEmailTestCase(unittest.HomeserverTestCase):
 
         # We need to manually add an email address otherwise the handler will do
         # nothing.
-        now = self.hs.clock.time_msec()
+        now = self.hs.get_clock().time_msec()
         self.get_success(
             self.store.user_add_threepid(
                 user_id=user_id,
@@ -843,7 +811,6 @@ class AccountValidityRenewalByEmailTestCase(unittest.HomeserverTestCase):
             "/_matrix/client/unstable/account_validity/send_mail",
             access_token=tok,
         )
-        self.render(request)
         self.assertEquals(channel.result["code"], b"200", channel.result)
 
         self.assertEqual(len(self.email_attempts), 1)
@@ -882,7 +849,7 @@ class AccountValidityBackgroundJobTestCase(unittest.HomeserverTestCase):
         """
         user_id = self.register_user("kermit_delta", "user")
 
-        now_ms = self.hs.clock.time_msec()
+        now_ms = self.hs.get_clock().time_msec()
         self.get_success(self.store._set_expiration_date_when_missing())
 
         res = self.get_success(self.store.get_expiration_ts_for_user(user_id))
diff --git a/tests/rest/client/v2_alpha/test_relations.py b/tests/rest/client/v2_alpha/test_relations.py
index 99c9f4e928..6cd4eb6624 100644
--- a/tests/rest/client/v2_alpha/test_relations.py
+++ b/tests/rest/client/v2_alpha/test_relations.py
@@ -65,7 +65,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/event/%s" % (self.room, event_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         self.assert_dict(
@@ -114,7 +113,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             % (self.room, self.parent_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         # We expect to get back a single pagination result, which is the full
@@ -160,7 +158,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
                 % (self.room, self.parent_id, from_token),
                 access_token=self.user_token,
             )
-            self.render(request)
             self.assertEquals(200, channel.code, channel.json_body)
 
             found_event_ids.extend(e["event_id"] for e in channel.json_body["chunk"])
@@ -219,7 +216,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
                 % (self.room, self.parent_id, from_token),
                 access_token=self.user_token,
             )
-            self.render(request)
             self.assertEquals(200, channel.code, channel.json_body)
 
             self.assertEqual(len(channel.json_body["chunk"]), 1, channel.json_body)
@@ -296,7 +292,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
                 ),
                 access_token=self.user_token,
             )
-            self.render(request)
             self.assertEquals(200, channel.code, channel.json_body)
 
             self.assertEqual(len(channel.json_body["chunk"]), 1, channel.json_body)
@@ -336,7 +331,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             % (self.room, self.parent_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         self.assertEquals(
@@ -369,7 +363,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             access_token=self.user_token,
             content={},
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         request, channel = self.make_request(
@@ -378,7 +371,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             % (self.room, self.parent_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         self.assertEquals(
@@ -396,7 +388,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             % (self.room, self.parent_id, RelationTypes.REPLACE),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(400, channel.code, channel.json_body)
 
     def test_aggregation_get_event(self):
@@ -428,7 +419,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/event/%s" % (self.room, self.parent_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         self.assertEquals(
@@ -465,7 +455,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/event/%s" % (self.room, self.parent_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         self.assertEquals(channel.json_body["content"], new_body)
@@ -523,7 +512,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             "/rooms/%s/event/%s" % (self.room, self.parent_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         self.assertEquals(channel.json_body["content"], new_body)
@@ -567,7 +555,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             % (self.room, original_event_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         self.assertIn("chunk", channel.json_body)
@@ -581,7 +568,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             access_token=self.user_token,
             content="{}",
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         # Try to check for remaining m.replace relations
@@ -591,7 +577,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             % (self.room, original_event_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         # Check that no relations are returned
@@ -624,7 +609,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             access_token=self.user_token,
             content="{}",
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         # Check that aggregations returns zero
@@ -634,7 +618,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             % (self.room, original_event_id),
             access_token=self.user_token,
         )
-        self.render(request)
         self.assertEquals(200, channel.code, channel.json_body)
 
         self.assertIn("chunk", channel.json_body)
@@ -680,7 +663,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             json.dumps(content).encode("utf-8"),
             access_token=access_token,
         )
-        self.render(request)
         return channel
 
     def _create_user(self, localpart):
diff --git a/tests/rest/client/v2_alpha/test_shared_rooms.py b/tests/rest/client/v2_alpha/test_shared_rooms.py
index 5ae72fd008..562a9c1ba4 100644
--- a/tests/rest/client/v2_alpha/test_shared_rooms.py
+++ b/tests/rest/client/v2_alpha/test_shared_rooms.py
@@ -47,7 +47,6 @@ class UserSharedRoomsTest(unittest.HomeserverTestCase):
             % other_user,
             access_token=token,
         )
-        self.render(request)
         return request, channel
 
     def test_shared_room_list_public(self):
diff --git a/tests/rest/client/v2_alpha/test_sync.py b/tests/rest/client/v2_alpha/test_sync.py
index a31e44c97e..31ac0fccb8 100644
--- a/tests/rest/client/v2_alpha/test_sync.py
+++ b/tests/rest/client/v2_alpha/test_sync.py
@@ -36,7 +36,6 @@ class FilterTestCase(unittest.HomeserverTestCase):
 
     def test_sync_argless(self):
         request, channel = self.make_request("GET", "/sync")
-        self.render(request)
 
         self.assertEqual(channel.code, 200)
         self.assertTrue(
@@ -57,7 +56,6 @@ class FilterTestCase(unittest.HomeserverTestCase):
         self.hs.config.use_presence = False
 
         request, channel = self.make_request("GET", "/sync")
-        self.render(request)
 
         self.assertEqual(channel.code, 200)
         self.assertTrue(
@@ -199,7 +197,6 @@ class SyncFilterTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/sync?filter=%s" % sync_filter, access_token=tok
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         return channel.json_body["rooms"]["join"][room_id]["timeline"]["events"]
@@ -253,13 +250,11 @@ class SyncTypingTests(unittest.HomeserverTestCase):
             typing_url % (room, other_user_id, other_access_token),
             b'{"typing": true, "timeout": 30000}',
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         request, channel = self.make_request(
             "GET", "/sync?access_token=%s" % (access_token,)
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         next_batch = channel.json_body["next_batch"]
 
@@ -269,7 +264,6 @@ class SyncTypingTests(unittest.HomeserverTestCase):
             typing_url % (room, other_user_id, other_access_token),
             b'{"typing": false}',
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         # Start typing.
@@ -278,14 +272,12 @@ class SyncTypingTests(unittest.HomeserverTestCase):
             typing_url % (room, other_user_id, other_access_token),
             b'{"typing": true, "timeout": 30000}',
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
 
         # Should return immediately
         request, channel = self.make_request(
             "GET", sync_url % (access_token, next_batch)
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         next_batch = channel.json_body["next_batch"]
 
@@ -300,7 +292,6 @@ class SyncTypingTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", sync_url % (access_token, next_batch)
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         next_batch = channel.json_body["next_batch"]
 
@@ -311,7 +302,6 @@ class SyncTypingTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", sync_url % (access_token, next_batch)
         )
-        self.render(request)
         self.assertEquals(200, channel.code)
         next_batch = channel.json_body["next_batch"]
 
@@ -320,10 +310,8 @@ class SyncTypingTests(unittest.HomeserverTestCase):
         typing._reset()
 
         # Now it SHOULD fail as it never completes!
-        request, channel = self.make_request(
-            "GET", sync_url % (access_token, next_batch)
-        )
-        self.assertRaises(TimedOutException, self.render, request)
+        with self.assertRaises(TimedOutException):
+            self.make_request("GET", sync_url % (access_token, next_batch))
 
 
 class UnreadMessagesTestCase(unittest.HomeserverTestCase):
@@ -401,7 +389,6 @@ class UnreadMessagesTestCase(unittest.HomeserverTestCase):
             body,
             access_token=self.tok,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.json_body)
 
         # Check that the unread counter is back to 0.
@@ -466,7 +453,6 @@ class UnreadMessagesTestCase(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", self.url % self.next_batch, access_token=self.tok,
         )
-        self.render(request)
 
         self.assertEqual(channel.code, 200, channel.json_body)
 
diff --git a/tests/rest/key/v2/test_remote_key_resource.py b/tests/rest/key/v2/test_remote_key_resource.py
index 6850c666be..fbcf8d5b86 100644
--- a/tests/rest/key/v2/test_remote_key_resource.py
+++ b/tests/rest/key/v2/test_remote_key_resource.py
@@ -32,7 +32,7 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.stringutils import random_string
 
 from tests import unittest
-from tests.server import FakeChannel, wait_until_result
+from tests.server import FakeChannel
 from tests.utils import default_config
 
 
@@ -41,7 +41,7 @@ class BaseRemoteKeyResourceTestCase(unittest.HomeserverTestCase):
         self.http_client = Mock()
         return self.setup_test_homeserver(http_client=self.http_client)
 
-    def create_test_json_resource(self):
+    def create_test_resource(self):
         return create_resource_tree(
             {"/_matrix/key/v2": KeyApiV2Resource(self.hs)}, root_resource=NoResource()
         )
@@ -94,7 +94,7 @@ class RemoteKeyResourceTestCase(BaseRemoteKeyResourceTestCase):
             % (server_name.encode("utf-8"), key_id.encode("utf-8")),
             b"1.1",
         )
-        wait_until_result(self.reactor, req)
+        channel.await_result()
         self.assertEqual(channel.code, 200)
         resp = channel.json_body
         return resp
@@ -190,7 +190,7 @@ class EndToEndPerspectivesTests(BaseRemoteKeyResourceTestCase):
             req.requestReceived(
                 b"POST", path.encode("utf-8"), b"1.1",
             )
-            wait_until_result(self.reactor, req)
+            channel.await_result()
             self.assertEqual(channel.code, 200)
             resp = channel.json_body
             return resp
diff --git a/tests/rest/media/v1/test_media_storage.py b/tests/rest/media/v1/test_media_storage.py
index 5f897d49cf..2a3b2a8f27 100644
--- a/tests/rest/media/v1/test_media_storage.py
+++ b/tests/rest/media/v1/test_media_storage.py
@@ -36,6 +36,7 @@ from synapse.rest.media.v1.media_storage import MediaStorage
 from synapse.rest.media.v1.storage_provider import FileStorageProviderBackend
 
 from tests import unittest
+from tests.server import FakeSite, make_request
 
 
 class MediaStorageTests(unittest.HomeserverTestCase):
@@ -227,8 +228,14 @@ class MediaRepoTests(unittest.HomeserverTestCase):
 
     def _req(self, content_disposition):
 
-        request, channel = self.make_request("GET", self.media_id, shorthand=False)
-        request.render(self.download_resource)
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(self.download_resource),
+            "GET",
+            self.media_id,
+            shorthand=False,
+            await_result=False,
+        )
         self.pump()
 
         # We've made one fetch, to example.com, using the media URL, and asking
@@ -317,10 +324,14 @@ class MediaRepoTests(unittest.HomeserverTestCase):
 
     def _test_thumbnail(self, method, expected_body, expected_found):
         params = "?width=32&height=32&method=" + method
-        request, channel = self.make_request(
-            "GET", self.media_id + params, shorthand=False
+        request, channel = make_request(
+            self.reactor,
+            FakeSite(self.thumbnail_resource),
+            "GET",
+            self.media_id + params,
+            shorthand=False,
+            await_result=False,
         )
-        request.render(self.thumbnail_resource)
         self.pump()
 
         headers = {
@@ -348,7 +359,6 @@ class MediaRepoTests(unittest.HomeserverTestCase):
                 channel.json_body,
                 {
                     "errcode": "M_NOT_FOUND",
-                    "error": "Not found [b'example.com', b'12345?width=32&height=32&method=%s']"
-                    % method,
+                    "error": "Not found [b'example.com', b'12345']",
                 },
             )
diff --git a/tests/rest/media/v1/test_url_preview.py b/tests/rest/media/v1/test_url_preview.py
index c00a7b9114..ccdc8c2ecf 100644
--- a/tests/rest/media/v1/test_url_preview.py
+++ b/tests/rest/media/v1/test_url_preview.py
@@ -133,13 +133,18 @@ class URLPreviewTests(unittest.HomeserverTestCase):
 
         self.reactor.nameResolver = Resolver()
 
+    def create_test_resource(self):
+        return self.hs.get_media_repository_resource()
+
     def test_cache_returns_correct_type(self):
         self.lookups["matrix.org"] = [(IPv4Address, "10.1.2.3")]
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://matrix.org", shorthand=False
+            "GET",
+            "preview_url?url=http://matrix.org",
+            shorthand=False,
+            await_result=False,
         )
-        request.render(self.preview_url)
         self.pump()
 
         client = self.reactor.tcpClients[0][2].buildProtocol(None)
@@ -160,10 +165,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
 
         # Check the cache returns the correct response
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://matrix.org", shorthand=False
+            "GET", "preview_url?url=http://matrix.org", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
 
         # Check the cache response has the same content
         self.assertEqual(channel.code, 200)
@@ -178,10 +181,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
 
         # Check the database cache returns the correct response
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://matrix.org", shorthand=False
+            "GET", "preview_url?url=http://matrix.org", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
 
         # Check the cache response has the same content
         self.assertEqual(channel.code, 200)
@@ -201,9 +202,11 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         )
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://matrix.org", shorthand=False
+            "GET",
+            "preview_url?url=http://matrix.org",
+            shorthand=False,
+            await_result=False,
         )
-        request.render(self.preview_url)
         self.pump()
 
         client = self.reactor.tcpClients[0][2].buildProtocol(None)
@@ -234,9 +237,11 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         )
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://matrix.org", shorthand=False
+            "GET",
+            "preview_url?url=http://matrix.org",
+            shorthand=False,
+            await_result=False,
         )
-        request.render(self.preview_url)
         self.pump()
 
         client = self.reactor.tcpClients[0][2].buildProtocol(None)
@@ -267,9 +272,11 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         )
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://matrix.org", shorthand=False
+            "GET",
+            "preview_url?url=http://matrix.org",
+            shorthand=False,
+            await_result=False,
         )
-        request.render(self.preview_url)
         self.pump()
 
         client = self.reactor.tcpClients[0][2].buildProtocol(None)
@@ -298,9 +305,11 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         self.lookups["example.com"] = [(IPv4Address, "10.1.2.3")]
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://example.com", shorthand=False
+            "GET",
+            "preview_url?url=http://example.com",
+            shorthand=False,
+            await_result=False,
         )
-        request.render(self.preview_url)
         self.pump()
 
         client = self.reactor.tcpClients[0][2].buildProtocol(None)
@@ -326,10 +335,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         self.lookups["example.com"] = [(IPv4Address, "192.168.1.1")]
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://example.com", shorthand=False
+            "GET", "preview_url?url=http://example.com", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
 
         # No requests made.
         self.assertEqual(len(self.reactor.tcpClients), 0)
@@ -349,10 +356,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         self.lookups["example.com"] = [(IPv4Address, "1.1.1.2")]
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://example.com", shorthand=False
+            "GET", "preview_url?url=http://example.com", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
 
         self.assertEqual(channel.code, 502)
         self.assertEqual(
@@ -368,10 +373,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         Blacklisted IP addresses, accessed directly, are not spidered.
         """
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://192.168.1.1", shorthand=False
+            "GET", "preview_url?url=http://192.168.1.1", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
 
         # No requests made.
         self.assertEqual(len(self.reactor.tcpClients), 0)
@@ -389,10 +392,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         Blacklisted IP ranges, accessed directly, are not spidered.
         """
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://1.1.1.2", shorthand=False
+            "GET", "preview_url?url=http://1.1.1.2", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
 
         self.assertEqual(channel.code, 403)
         self.assertEqual(
@@ -411,9 +412,11 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         self.lookups["example.com"] = [(IPv4Address, "1.1.1.1")]
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://example.com", shorthand=False
+            "GET",
+            "preview_url?url=http://example.com",
+            shorthand=False,
+            await_result=False,
         )
-        request.render(self.preview_url)
         self.pump()
 
         client = self.reactor.tcpClients[0][2].buildProtocol(None)
@@ -446,10 +449,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         ]
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://example.com", shorthand=False
+            "GET", "preview_url?url=http://example.com", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
         self.assertEqual(channel.code, 502)
         self.assertEqual(
             channel.json_body,
@@ -468,10 +469,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         ]
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://example.com", shorthand=False
+            "GET", "preview_url?url=http://example.com", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
 
         # No requests made.
         self.assertEqual(len(self.reactor.tcpClients), 0)
@@ -491,10 +490,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         self.lookups["example.com"] = [(IPv6Address, "2001:800::1")]
 
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://example.com", shorthand=False
+            "GET", "preview_url?url=http://example.com", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
 
         self.assertEqual(channel.code, 502)
         self.assertEqual(
@@ -510,10 +507,8 @@ class URLPreviewTests(unittest.HomeserverTestCase):
         OPTIONS returns the OPTIONS.
         """
         request, channel = self.make_request(
-            "OPTIONS", "url_preview?url=http://example.com", shorthand=False
+            "OPTIONS", "preview_url?url=http://example.com", shorthand=False
         )
-        request.render(self.preview_url)
-        self.pump()
         self.assertEqual(channel.code, 200)
         self.assertEqual(channel.json_body, {})
 
@@ -525,9 +520,11 @@ class URLPreviewTests(unittest.HomeserverTestCase):
 
         # Build and make a request to the server
         request, channel = self.make_request(
-            "GET", "url_preview?url=http://example.com", shorthand=False
+            "GET",
+            "preview_url?url=http://example.com",
+            shorthand=False,
+            await_result=False,
         )
-        request.render(self.preview_url)
         self.pump()
 
         # Extract Synapse's tcp client
@@ -598,10 +595,10 @@ class URLPreviewTests(unittest.HomeserverTestCase):
 
             request, channel = self.make_request(
                 "GET",
-                "url_preview?url=http://twitter.com/matrixdotorg/status/12345",
+                "preview_url?url=http://twitter.com/matrixdotorg/status/12345",
                 shorthand=False,
+                await_result=False,
             )
-            request.render(self.preview_url)
             self.pump()
 
             client = self.reactor.tcpClients[0][2].buildProtocol(None)
@@ -663,10 +660,10 @@ class URLPreviewTests(unittest.HomeserverTestCase):
 
             request, channel = self.make_request(
                 "GET",
-                "url_preview?url=http://twitter.com/matrixdotorg/status/12345",
+                "preview_url?url=http://twitter.com/matrixdotorg/status/12345",
                 shorthand=False,
+                await_result=False,
             )
-            request.render(self.preview_url)
             self.pump()
 
             client = self.reactor.tcpClients[0][2].buildProtocol(None)
diff --git a/tests/rest/test_health.py b/tests/rest/test_health.py
index 2d021f6565..02a46e5fda 100644
--- a/tests/rest/test_health.py
+++ b/tests/rest/test_health.py
@@ -20,15 +20,12 @@ from tests import unittest
 
 
 class HealthCheckTests(unittest.HomeserverTestCase):
-    def setUp(self):
-        super().setUp()
-
+    def create_test_resource(self):
         # replace the JsonResource with a HealthResource.
-        self.resource = HealthResource()
+        return HealthResource()
 
     def test_health(self):
         request, channel = self.make_request("GET", "/health", shorthand=False)
-        self.render(request)
 
         self.assertEqual(request.code, 200)
         self.assertEqual(channel.result["body"], b"OK")
diff --git a/tests/rest/test_well_known.py b/tests/rest/test_well_known.py
index dcd65c2a50..6a930f4148 100644
--- a/tests/rest/test_well_known.py
+++ b/tests/rest/test_well_known.py
@@ -20,11 +20,9 @@ from tests import unittest
 
 
 class WellKnownTests(unittest.HomeserverTestCase):
-    def setUp(self):
-        super().setUp()
-
+    def create_test_resource(self):
         # replace the JsonResource with a WellKnownResource
-        self.resource = WellKnownResource(self.hs)
+        return WellKnownResource(self.hs)
 
     def test_well_known(self):
         self.hs.config.public_baseurl = "https://tesths"
@@ -33,7 +31,6 @@ class WellKnownTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/.well-known/matrix/client", shorthand=False
         )
-        self.render(request)
 
         self.assertEqual(request.code, 200)
         self.assertEqual(
@@ -50,6 +47,5 @@ class WellKnownTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/.well-known/matrix/client", shorthand=False
         )
-        self.render(request)
 
         self.assertEqual(request.code, 404)
diff --git a/tests/rulecheck/test_domainrulecheck.py b/tests/rulecheck/test_domainrulecheck.py
index 1accc70dc9..0937f304cf 100644
--- a/tests/rulecheck/test_domainrulecheck.py
+++ b/tests/rulecheck/test_domainrulecheck.py
@@ -22,7 +22,7 @@ from synapse.rest.client.v1 import login, room
 from synapse.rulecheck.domain_rule_checker import DomainRuleChecker
 
 from tests import unittest
-from tests.server import make_request, render
+from tests.server import make_request
 
 
 class DomainRuleCheckerTestCase(unittest.TestCase):
@@ -317,7 +317,6 @@ class DomainRuleCheckerRoomTestCase(unittest.HomeserverTestCase):
             {"address": "foo@bar.com", "medium": "email", "id_server": "localhost"},
             access_token=self.normal_access_token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 403, channel.result["body"])
 
     def _create_room(self, token, content={}):
@@ -325,10 +324,10 @@ class DomainRuleCheckerRoomTestCase(unittest.HomeserverTestCase):
 
         request, channel = make_request(
             self.hs.get_reactor(),
+            self.site,
             "POST",
             path,
             content=json.dumps(content).encode("utf8"),
         )
-        render(request, self.resource, self.hs.get_reactor())
 
         return channel
diff --git a/tests/server.py b/tests/server.py
index b404ad4e2a..a51ad0c14e 100644
--- a/tests/server.py
+++ b/tests/server.py
@@ -1,8 +1,11 @@
 import json
 import logging
+from collections import deque
 from io import SEEK_END, BytesIO
+from typing import Callable, Iterable, Optional, Tuple, Union
 
 import attr
+from typing_extensions import Deque
 from zope.interface import implementer
 
 from twisted.internet import address, threads, udp
@@ -16,8 +19,8 @@ from twisted.internet.interfaces import (
 )
 from twisted.python.failure import Failure
 from twisted.test.proto_helpers import AccumulatingProtocol, MemoryReactorClock
-from twisted.web.http import unquote
 from twisted.web.http_headers import Headers
+from twisted.web.resource import IResource
 from twisted.web.server import Site
 
 from synapse.http.site import SynapseRequest
@@ -43,7 +46,7 @@ class FakeChannel:
 
     site = attr.ib(type=Site)
     _reactor = attr.ib()
-    result = attr.ib(default=attr.Factory(dict))
+    result = attr.ib(type=dict, default=attr.Factory(dict))
     _producer = None
 
     @property
@@ -114,6 +117,25 @@ class FakeChannel:
     def transport(self):
         return self
 
+    def await_result(self, timeout: int = 100) -> None:
+        """
+        Wait until the request is finished.
+        """
+        self._reactor.run()
+        x = 0
+
+        while not self.result.get("done"):
+            # If there's a producer, tell it to resume producing so we get content
+            if self._producer:
+                self._producer.resumeProducing()
+
+            x += 1
+
+            if x > timeout:
+                raise TimedOutException("Timed out waiting for request to finish.")
+
+            self._reactor.advance(0.1)
+
 
 class FakeSite:
     """
@@ -125,9 +147,21 @@ class FakeSite:
     site_tag = "test"
     access_logger = logging.getLogger("synapse.access.http.fake")
 
+    def __init__(self, resource: IResource):
+        """
+
+        Args:
+            resource: the resource to be used for rendering all requests
+        """
+        self._resource = resource
+
+    def getResourceFor(self, request):
+        return self._resource
+
 
 def make_request(
     reactor,
+    site: Site,
     method,
     path,
     content=b"",
@@ -136,12 +170,19 @@ def make_request(
     shorthand=True,
     federation_auth_origin=None,
     content_is_form=False,
+    await_result: bool = True,
+    custom_headers: Optional[
+        Iterable[Tuple[Union[bytes, str], Union[bytes, str]]]
+    ] = None,
 ):
     """
-    Make a web request using the given method and path, feed it the
-    content, and return the Request and the Channel underneath.
+    Make a web request using the given method, path and content, and render it
+
+    Returns the Request and the Channel underneath.
 
     Args:
+        site: The twisted Site to use to render the request
+
         method (bytes/unicode): The HTTP request method ("verb").
         path (bytes/unicode): The HTTP path, suitably URL encoded (e.g.
         escaped UTF-8 & spaces and such).
@@ -154,6 +195,12 @@ def make_request(
         content_is_form: Whether the content is URL encoded form data. Adds the
             'Content-Type': 'application/x-www-form-urlencoded' header.
 
+        custom_headers: (name, value) pairs to add as request headers
+
+        await_result: whether to wait for the request to complete rendering. If true,
+             will pump the reactor until the the renderer tells the channel the request
+             is finished.
+
     Returns:
         Tuple[synapse.http.site.SynapseRequest, channel]
     """
@@ -175,18 +222,17 @@ def make_request(
     if not path.startswith(b"/"):
         path = b"/" + path
 
+    if isinstance(content, dict):
+        content = json.dumps(content).encode("utf8")
     if isinstance(content, str):
         content = content.encode("utf8")
 
-    site = FakeSite()
     channel = FakeChannel(site, reactor)
 
     req = request(channel)
-    req.process = lambda: b""
     req.content = BytesIO(content)
     # Twisted expects to be at the end of the content when parsing the request.
     req.content.seek(SEEK_END)
-    req.postpath = list(map(unquote, path[1:].split(b"/")))
 
     if access_token:
         req.requestHeaders.addRawHeader(
@@ -208,37 +254,18 @@ def make_request(
             # Assume the body is JSON
             req.requestHeaders.addRawHeader(b"Content-Type", b"application/json")
 
+    if custom_headers:
+        for k, v in custom_headers:
+            req.requestHeaders.addRawHeader(k, v)
+
     req.requestReceived(method, path, b"1.1")
 
+    if await_result:
+        channel.await_result()
+
     return req, channel
 
 
-def wait_until_result(clock, request, timeout=100):
-    """
-    Wait until the request is finished.
-    """
-    clock.run()
-    x = 0
-
-    while not request.finished:
-
-        # If there's a producer, tell it to resume producing so we get content
-        if request._channel._producer:
-            request._channel._producer.resumeProducing()
-
-        x += 1
-
-        if x > timeout:
-            raise TimedOutException("Timed out waiting for request to finish.")
-
-        clock.advance(0.1)
-
-
-def render(request, resource, clock):
-    request.render(resource)
-    wait_until_result(clock, request)
-
-
 @implementer(IReactorPluggableNameResolver)
 class ThreadedMemoryReactorClock(MemoryReactorClock):
     """
@@ -251,6 +278,7 @@ class ThreadedMemoryReactorClock(MemoryReactorClock):
         self._tcp_callbacks = {}
         self._udp = []
         lookups = self.lookups = {}
+        self._thread_callbacks = deque()  # type: Deque[Callable[[], None]]()
 
         @implementer(IResolverSimple)
         class FakeResolver:
@@ -272,10 +300,10 @@ class ThreadedMemoryReactorClock(MemoryReactorClock):
         """
         Make the callback fire in the next reactor iteration.
         """
-        d = Deferred()
-        d.addCallback(lambda x: callback(*args, **kwargs))
-        self.callLater(0, d.callback, True)
-        return d
+        cb = lambda: callback(*args, **kwargs)
+        # it's not safe to call callLater() here, so we append the callback to a
+        # separate queue.
+        self._thread_callbacks.append(cb)
 
     def getThreadPool(self):
         return self.threadpool
@@ -303,6 +331,30 @@ class ThreadedMemoryReactorClock(MemoryReactorClock):
 
         return conn
 
+    def advance(self, amount):
+        # first advance our reactor's time, and run any "callLater" callbacks that
+        # makes ready
+        super().advance(amount)
+
+        # now run any "callFromThread" callbacks
+        while True:
+            try:
+                callback = self._thread_callbacks.popleft()
+            except IndexError:
+                break
+            callback()
+
+            # check for more "callLater" callbacks added by the thread callback
+            # This isn't required in a regular reactor, but it ends up meaning that
+            # our database queries can complete in a single call to `advance` [1] which
+            # simplifies tests.
+            #
+            # [1]: we replace the threadpool backing the db connection pool with a
+            # mock ThreadPool which doesn't really use threads; but we still use
+            # reactor.callFromThread to feed results back from the db functions to the
+            # main thread.
+            super().advance(0)
+
 
 class ThreadPool:
     """
@@ -339,8 +391,6 @@ def setup_test_homeserver(cleanup_func, *args, **kwargs):
     """
     server = _sth(cleanup_func, *args, **kwargs)
 
-    database = server.config.database.get_single_database()
-
     # Make the thread pool synchronous.
     clock = server.get_clock()
 
@@ -354,7 +404,7 @@ def setup_test_homeserver(cleanup_func, *args, **kwargs):
                 pool._runWithConnection,
                 func,
                 *args,
-                **kwargs
+                **kwargs,
             )
 
         def runInteraction(interaction, *args, **kwargs):
@@ -364,7 +414,7 @@ def setup_test_homeserver(cleanup_func, *args, **kwargs):
                 pool._runInteraction,
                 interaction,
                 *args,
-                **kwargs
+                **kwargs,
             )
 
         pool.runWithConnection = runWithConnection
@@ -372,6 +422,10 @@ def setup_test_homeserver(cleanup_func, *args, **kwargs):
         pool.threadpool = ThreadPool(clock._reactor)
         pool.running = True
 
+    # We've just changed the Databases to run DB transactions on the same
+    # thread, so we need to disable the dedicated thread behaviour.
+    server.get_datastores().main.USE_DEDICATED_DB_THREADS_FOR_EVENT_FETCHING = False
+
     return server
 
 
@@ -541,12 +595,10 @@ def connect_client(reactor: IReactorTCP, client_id: int) -> AccumulatingProtocol
         reactor
         factory: The connecting factory to build.
     """
-    factory = reactor.tcpClients[client_id][2]
+    factory = reactor.tcpClients.pop(client_id)[2]
     client = factory.buildProtocol(None)
     server = AccumulatingProtocol()
     server.makeConnection(FakeTransport(client, reactor))
     client.makeConnection(FakeTransport(server, reactor))
 
-    reactor.tcpClients.pop(client_id)
-
     return client, server
diff --git a/tests/server_notices/test_consent.py b/tests/server_notices/test_consent.py
index 872039c8f1..e0a9cd93ac 100644
--- a/tests/server_notices/test_consent.py
+++ b/tests/server_notices/test_consent.py
@@ -73,7 +73,6 @@ class ConsentNoticesTests(unittest.HomeserverTestCase):
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/sync", access_token=self.access_token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # Get the Room ID to join
@@ -85,14 +84,12 @@ class ConsentNoticesTests(unittest.HomeserverTestCase):
             "/_matrix/client/r0/rooms/" + room_id + "/join",
             access_token=self.access_token,
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # Sync again, to get the message in the room
         request, channel = self.make_request(
             "GET", "/_matrix/client/r0/sync", access_token=self.access_token
         )
-        self.render(request)
         self.assertEqual(channel.code, 200)
 
         # Get the message
diff --git a/tests/server_notices/test_resource_limits_server_notices.py b/tests/server_notices/test_resource_limits_server_notices.py
index 6382b19dc3..9c8027a5b2 100644
--- a/tests/server_notices/test_resource_limits_server_notices.py
+++ b/tests/server_notices/test_resource_limits_server_notices.py
@@ -306,7 +306,6 @@ class TestResourceLimitsServerNoticesWithRealRooms(unittest.HomeserverTestCase):
         tok = self.login("user", "password")
 
         request, channel = self.make_request("GET", "/sync?timeout=0", access_token=tok)
-        self.render(request)
 
         invites = channel.json_body["rooms"]["invite"]
         self.assertEqual(len(invites), 0, invites)
@@ -320,7 +319,6 @@ class TestResourceLimitsServerNoticesWithRealRooms(unittest.HomeserverTestCase):
         # Sync again to retrieve the events in the room, so we can check whether this
         # room has a notice in it.
         request, channel = self.make_request("GET", "/sync?timeout=0", access_token=tok)
-        self.render(request)
 
         # Scan the events in the room to search for a message from the server notices
         # user.
@@ -358,7 +356,6 @@ class TestResourceLimitsServerNoticesWithRealRooms(unittest.HomeserverTestCase):
             request, channel = self.make_request(
                 "GET", "/sync?timeout=0", access_token=tok,
             )
-            self.render(request)
 
             # Also retrieves the list of invites for this user. We don't care about that
             # one except if we're processing the last user, which should have received an
diff --git a/tests/storage/test__base.py b/tests/storage/test__base.py
index f5afed017c..1ac4ebc61d 100644
--- a/tests/storage/test__base.py
+++ b/tests/storage/test__base.py
@@ -15,308 +15,9 @@
 # limitations under the License.
 
 
-from mock import Mock
-
-from twisted.internet import defer
-
-from synapse.util.async_helpers import ObservableDeferred
-from synapse.util.caches.descriptors import Cache, cached
-
 from tests import unittest
 
 
-class CacheTestCase(unittest.HomeserverTestCase):
-    def prepare(self, reactor, clock, homeserver):
-        self.cache = Cache("test")
-
-    def test_empty(self):
-        failed = False
-        try:
-            self.cache.get("foo")
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
-
-    def test_hit(self):
-        self.cache.prefill("foo", 123)
-
-        self.assertEquals(self.cache.get("foo"), 123)
-
-    def test_invalidate(self):
-        self.cache.prefill(("foo",), 123)
-        self.cache.invalidate(("foo",))
-
-        failed = False
-        try:
-            self.cache.get(("foo",))
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
-
-    def test_eviction(self):
-        cache = Cache("test", max_entries=2)
-
-        cache.prefill(1, "one")
-        cache.prefill(2, "two")
-        cache.prefill(3, "three")  # 1 will be evicted
-
-        failed = False
-        try:
-            cache.get(1)
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
-
-        cache.get(2)
-        cache.get(3)
-
-    def test_eviction_lru(self):
-        cache = Cache("test", max_entries=2)
-
-        cache.prefill(1, "one")
-        cache.prefill(2, "two")
-
-        # Now access 1 again, thus causing 2 to be least-recently used
-        cache.get(1)
-
-        cache.prefill(3, "three")
-
-        failed = False
-        try:
-            cache.get(2)
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
-
-        cache.get(1)
-        cache.get(3)
-
-
-class CacheDecoratorTestCase(unittest.HomeserverTestCase):
-    @defer.inlineCallbacks
-    def test_passthrough(self):
-        class A:
-            @cached()
-            def func(self, key):
-                return key
-
-        a = A()
-
-        self.assertEquals((yield a.func("foo")), "foo")
-        self.assertEquals((yield a.func("bar")), "bar")
-
-    @defer.inlineCallbacks
-    def test_hit(self):
-        callcount = [0]
-
-        class A:
-            @cached()
-            def func(self, key):
-                callcount[0] += 1
-                return key
-
-        a = A()
-        yield a.func("foo")
-
-        self.assertEquals(callcount[0], 1)
-
-        self.assertEquals((yield a.func("foo")), "foo")
-        self.assertEquals(callcount[0], 1)
-
-    @defer.inlineCallbacks
-    def test_invalidate(self):
-        callcount = [0]
-
-        class A:
-            @cached()
-            def func(self, key):
-                callcount[0] += 1
-                return key
-
-        a = A()
-        yield a.func("foo")
-
-        self.assertEquals(callcount[0], 1)
-
-        a.func.invalidate(("foo",))
-
-        yield a.func("foo")
-
-        self.assertEquals(callcount[0], 2)
-
-    def test_invalidate_missing(self):
-        class A:
-            @cached()
-            def func(self, key):
-                return key
-
-        A().func.invalidate(("what",))
-
-    @defer.inlineCallbacks
-    def test_max_entries(self):
-        callcount = [0]
-
-        class A:
-            @cached(max_entries=10)
-            def func(self, key):
-                callcount[0] += 1
-                return key
-
-        a = A()
-
-        for k in range(0, 12):
-            yield a.func(k)
-
-        self.assertEquals(callcount[0], 12)
-
-        # There must have been at least 2 evictions, meaning if we calculate
-        # all 12 values again, we must get called at least 2 more times
-        for k in range(0, 12):
-            yield a.func(k)
-
-        self.assertTrue(
-            callcount[0] >= 14, msg="Expected callcount >= 14, got %d" % (callcount[0])
-        )
-
-    def test_prefill(self):
-        callcount = [0]
-
-        d = defer.succeed(123)
-
-        class A:
-            @cached()
-            def func(self, key):
-                callcount[0] += 1
-                return d
-
-        a = A()
-
-        a.func.prefill(("foo",), ObservableDeferred(d))
-
-        self.assertEquals(a.func("foo").result, d.result)
-        self.assertEquals(callcount[0], 0)
-
-    @defer.inlineCallbacks
-    def test_invalidate_context(self):
-        callcount = [0]
-        callcount2 = [0]
-
-        class A:
-            @cached()
-            def func(self, key):
-                callcount[0] += 1
-                return key
-
-            @cached(cache_context=True)
-            def func2(self, key, cache_context):
-                callcount2[0] += 1
-                return self.func(key, on_invalidate=cache_context.invalidate)
-
-        a = A()
-        yield a.func2("foo")
-
-        self.assertEquals(callcount[0], 1)
-        self.assertEquals(callcount2[0], 1)
-
-        a.func.invalidate(("foo",))
-        yield a.func("foo")
-
-        self.assertEquals(callcount[0], 2)
-        self.assertEquals(callcount2[0], 1)
-
-        yield a.func2("foo")
-
-        self.assertEquals(callcount[0], 2)
-        self.assertEquals(callcount2[0], 2)
-
-    @defer.inlineCallbacks
-    def test_eviction_context(self):
-        callcount = [0]
-        callcount2 = [0]
-
-        class A:
-            @cached(max_entries=2)
-            def func(self, key):
-                callcount[0] += 1
-                return key
-
-            @cached(cache_context=True)
-            def func2(self, key, cache_context):
-                callcount2[0] += 1
-                return self.func(key, on_invalidate=cache_context.invalidate)
-
-        a = A()
-        yield a.func2("foo")
-        yield a.func2("foo2")
-
-        self.assertEquals(callcount[0], 2)
-        self.assertEquals(callcount2[0], 2)
-
-        yield a.func2("foo")
-        self.assertEquals(callcount[0], 2)
-        self.assertEquals(callcount2[0], 2)
-
-        yield a.func("foo3")
-
-        self.assertEquals(callcount[0], 3)
-        self.assertEquals(callcount2[0], 2)
-
-        yield a.func2("foo")
-
-        self.assertEquals(callcount[0], 4)
-        self.assertEquals(callcount2[0], 3)
-
-    @defer.inlineCallbacks
-    def test_double_get(self):
-        callcount = [0]
-        callcount2 = [0]
-
-        class A:
-            @cached()
-            def func(self, key):
-                callcount[0] += 1
-                return key
-
-            @cached(cache_context=True)
-            def func2(self, key, cache_context):
-                callcount2[0] += 1
-                return self.func(key, on_invalidate=cache_context.invalidate)
-
-        a = A()
-        a.func2.cache.cache = Mock(wraps=a.func2.cache.cache)
-
-        yield a.func2("foo")
-
-        self.assertEquals(callcount[0], 1)
-        self.assertEquals(callcount2[0], 1)
-
-        a.func2.invalidate(("foo",))
-        self.assertEquals(a.func2.cache.cache.pop.call_count, 1)
-
-        yield a.func2("foo")
-        a.func2.invalidate(("foo",))
-        self.assertEquals(a.func2.cache.cache.pop.call_count, 2)
-
-        self.assertEquals(callcount[0], 1)
-        self.assertEquals(callcount2[0], 2)
-
-        a.func.invalidate(("foo",))
-        self.assertEquals(a.func2.cache.cache.pop.call_count, 3)
-        yield a.func("foo")
-
-        self.assertEquals(callcount[0], 2)
-        self.assertEquals(callcount2[0], 2)
-
-        yield a.func2("foo")
-
-        self.assertEquals(callcount[0], 2)
-        self.assertEquals(callcount2[0], 3)
-
-
 class UpsertManyTests(unittest.HomeserverTestCase):
     def prepare(self, reactor, clock, hs):
         self.storage = hs.get_datastore()
diff --git a/tests/storage/test_appservice.py b/tests/storage/test_appservice.py
index 46f94914ff..1ce29af5fd 100644
--- a/tests/storage/test_appservice.py
+++ b/tests/storage/test_appservice.py
@@ -58,7 +58,7 @@ class ApplicationServiceStoreTestCase(unittest.TestCase):
         # must be done after inserts
         database = hs.get_datastores().databases[0]
         self.store = ApplicationServiceStore(
-            database, make_conn(database._database_config, database.engine), hs
+            database, make_conn(database._database_config, database.engine, "test"), hs
         )
 
     def tearDown(self):
@@ -132,7 +132,7 @@ class ApplicationServiceTransactionStoreTestCase(unittest.TestCase):
 
         db_config = hs.config.get_single_database()
         self.store = TestTransactionStore(
-            database, make_conn(db_config, self.engine), hs
+            database, make_conn(db_config, self.engine, "test"), hs
         )
 
     def _add_service(self, url, as_token, id):
@@ -244,7 +244,7 @@ class ApplicationServiceTransactionStoreTestCase(unittest.TestCase):
         service = Mock(id=self.as_list[0]["id"])
         events = [Mock(event_id="e1"), Mock(event_id="e2")]
         txn = yield defer.ensureDeferred(
-            self.store.create_appservice_txn(service, events)
+            self.store.create_appservice_txn(service, events, [])
         )
         self.assertEquals(txn.id, 1)
         self.assertEquals(txn.events, events)
@@ -258,7 +258,7 @@ class ApplicationServiceTransactionStoreTestCase(unittest.TestCase):
         yield self._insert_txn(service.id, 9644, events)
         yield self._insert_txn(service.id, 9645, events)
         txn = yield defer.ensureDeferred(
-            self.store.create_appservice_txn(service, events)
+            self.store.create_appservice_txn(service, events, [])
         )
         self.assertEquals(txn.id, 9646)
         self.assertEquals(txn.events, events)
@@ -270,7 +270,7 @@ class ApplicationServiceTransactionStoreTestCase(unittest.TestCase):
         events = [Mock(event_id="e1"), Mock(event_id="e2")]
         yield self._set_last_txn(service.id, 9643)
         txn = yield defer.ensureDeferred(
-            self.store.create_appservice_txn(service, events)
+            self.store.create_appservice_txn(service, events, [])
         )
         self.assertEquals(txn.id, 9644)
         self.assertEquals(txn.events, events)
@@ -293,7 +293,7 @@ class ApplicationServiceTransactionStoreTestCase(unittest.TestCase):
         yield self._insert_txn(self.as_list[3]["id"], 9643, events)
 
         txn = yield defer.ensureDeferred(
-            self.store.create_appservice_txn(service, events)
+            self.store.create_appservice_txn(service, events, [])
         )
         self.assertEquals(txn.id, 9644)
         self.assertEquals(txn.events, events)
@@ -410,6 +410,62 @@ class ApplicationServiceTransactionStoreTestCase(unittest.TestCase):
         )
 
 
+class ApplicationServiceStoreTypeStreamIds(unittest.HomeserverTestCase):
+    def make_homeserver(self, reactor, clock):
+        hs = self.setup_test_homeserver()
+        return hs
+
+    def prepare(self, hs, reactor, clock):
+        self.service = Mock(id="foo")
+        self.store = self.hs.get_datastore()
+        self.get_success(self.store.set_appservice_state(self.service, "up"))
+
+    def test_get_type_stream_id_for_appservice_no_value(self):
+        value = self.get_success(
+            self.store.get_type_stream_id_for_appservice(self.service, "read_receipt")
+        )
+        self.assertEquals(value, 0)
+
+        value = self.get_success(
+            self.store.get_type_stream_id_for_appservice(self.service, "presence")
+        )
+        self.assertEquals(value, 0)
+
+    def test_get_type_stream_id_for_appservice_invalid_type(self):
+        self.get_failure(
+            self.store.get_type_stream_id_for_appservice(self.service, "foobar"),
+            ValueError,
+        )
+
+    def test_set_type_stream_id_for_appservice(self):
+        read_receipt_value = 1024
+        self.get_success(
+            self.store.set_type_stream_id_for_appservice(
+                self.service, "read_receipt", read_receipt_value
+            )
+        )
+        result = self.get_success(
+            self.store.get_type_stream_id_for_appservice(self.service, "read_receipt")
+        )
+        self.assertEqual(result, read_receipt_value)
+
+        self.get_success(
+            self.store.set_type_stream_id_for_appservice(
+                self.service, "presence", read_receipt_value
+            )
+        )
+        result = self.get_success(
+            self.store.get_type_stream_id_for_appservice(self.service, "presence")
+        )
+        self.assertEqual(result, read_receipt_value)
+
+    def test_set_type_stream_id_for_appservice_invalid_type(self):
+        self.get_failure(
+            self.store.set_type_stream_id_for_appservice(self.service, "foobar", 1024),
+            ValueError,
+        )
+
+
 # required for ApplicationServiceTransactionStoreTestCase tests
 class TestTransactionStore(ApplicationServiceTransactionStore, ApplicationServiceStore):
     def __init__(self, database: DatabasePool, db_conn, hs):
@@ -448,7 +504,7 @@ class ApplicationServiceStoreConfigTestCase(unittest.TestCase):
 
         database = hs.get_datastores().databases[0]
         ApplicationServiceStore(
-            database, make_conn(database._database_config, database.engine), hs
+            database, make_conn(database._database_config, database.engine, "test"), hs
         )
 
     @defer.inlineCallbacks
@@ -467,7 +523,9 @@ class ApplicationServiceStoreConfigTestCase(unittest.TestCase):
         with self.assertRaises(ConfigError) as cm:
             database = hs.get_datastores().databases[0]
             ApplicationServiceStore(
-                database, make_conn(database._database_config, database.engine), hs
+                database,
+                make_conn(database._database_config, database.engine, "test"),
+                hs,
             )
 
         e = cm.exception
@@ -491,7 +549,9 @@ class ApplicationServiceStoreConfigTestCase(unittest.TestCase):
         with self.assertRaises(ConfigError) as cm:
             database = hs.get_datastores().databases[0]
             ApplicationServiceStore(
-                database, make_conn(database._database_config, database.engine), hs
+                database,
+                make_conn(database._database_config, database.engine, "test"),
+                hs,
             )
 
         e = cm.exception
diff --git a/tests/storage/test_cleanup_extrems.py b/tests/storage/test_cleanup_extrems.py
index 080761d1d2..c13a57dad1 100644
--- a/tests/storage/test_cleanup_extrems.py
+++ b/tests/storage/test_cleanup_extrems.py
@@ -22,7 +22,7 @@ import synapse.rest.admin
 from synapse.api.constants import EventTypes
 from synapse.rest.client.v1 import login, room
 from synapse.storage import prepare_database
-from synapse.types import Requester, UserID
+from synapse.types import UserID, create_requester
 
 from tests.unittest import HomeserverTestCase
 
@@ -38,7 +38,7 @@ class CleanupExtremBackgroundUpdateStoreTestCase(HomeserverTestCase):
 
         # Create a test user and room
         self.user = UserID("alice", "test")
-        self.requester = Requester(self.user, None, False, False, None, None)
+        self.requester = create_requester(self.user)
         info, _ = self.get_success(self.room_creator.create_room(self.requester, {}))
         self.room_id = info["room_id"]
 
@@ -260,7 +260,7 @@ class CleanupExtremDummyEventsTestCase(HomeserverTestCase):
         # Create a test user and room
         self.user = UserID.from_string(self.register_user("user1", "password"))
         self.token1 = self.login("user1", "password")
-        self.requester = Requester(self.user, None, False, False, None, None)
+        self.requester = create_requester(self.user)
         info, _ = self.get_success(self.room_creator.create_room(self.requester, {}))
         self.room_id = info["room_id"]
         self.event_creator = homeserver.get_event_creation_handler()
@@ -309,36 +309,6 @@ class CleanupExtremDummyEventsTestCase(HomeserverTestCase):
         )
         self.assertTrue(len(latest_event_ids) < 10, len(latest_event_ids))
 
-    @patch("synapse.handlers.message._DUMMY_EVENT_ROOM_EXCLUSION_EXPIRY", new=0)
-    def test_send_dummy_event_without_consent(self):
-        self._create_extremity_rich_graph()
-        self._enable_consent_checking()
-
-        # Pump the reactor repeatedly so that the background updates have a
-        # chance to run. Attempt to add dummy event with user that has not consented
-        # Check that dummy event send fails.
-        self.pump(10 * 60)
-        latest_event_ids = self.get_success(
-            self.store.get_latest_event_ids_in_room(self.room_id)
-        )
-        self.assertTrue(len(latest_event_ids) == self.EXTREMITIES_COUNT)
-
-        # Create new user, and add consent
-        user2 = self.register_user("user2", "password")
-        token2 = self.login("user2", "password")
-        self.get_success(
-            self.store.user_set_consent_version(user2, self.CONSENT_VERSION)
-        )
-        self.helper.join(self.room_id, user2, tok=token2)
-
-        # Background updates should now cause a dummy event to be added to the graph
-        self.pump(10 * 60)
-
-        latest_event_ids = self.get_success(
-            self.store.get_latest_event_ids_in_room(self.room_id)
-        )
-        self.assertTrue(len(latest_event_ids) < 10, len(latest_event_ids))
-
     @patch("synapse.handlers.message._DUMMY_EVENT_ROOM_EXCLUSION_EXPIRY", new=250)
     def test_expiry_logic(self):
         """Simple test to ensure that _expire_rooms_to_exclude_from_dummy_event_insertion()
diff --git a/tests/storage/test_client_ips.py b/tests/storage/test_client_ips.py
index 755c70db31..a69117c5a9 100644
--- a/tests/storage/test_client_ips.py
+++ b/tests/storage/test_client_ips.py
@@ -21,6 +21,7 @@ from synapse.http.site import XForwardedForRequest
 from synapse.rest.client.v1 import login
 
 from tests import unittest
+from tests.server import make_request
 from tests.test_utils import make_awaitable
 from tests.unittest import override_config
 
@@ -408,18 +409,18 @@ class ClientIpAuthTestCase(unittest.HomeserverTestCase):
         # Advance to a known time
         self.reactor.advance(123456 - self.reactor.seconds())
 
-        request, channel = self.make_request(
-            "GET",
-            "/_matrix/client/r0/admin/users/" + self.user_id,
-            access_token=access_token,
-            **make_request_args
-        )
-        request.requestHeaders.addRawHeader(b"User-Agent", b"Mozzila pizza")
+        headers1 = {b"User-Agent": b"Mozzila pizza"}
+        headers1.update(headers)
 
-        # Add the optional headers
-        for h, v in headers.items():
-            request.requestHeaders.addRawHeader(h, v)
-        self.render(request)
+        make_request(
+            self.reactor,
+            self.site,
+            "GET",
+            "/_synapse/admin/v1/users/" + self.user_id,
+            access_token=access_token,
+            custom_headers=headers1.items(),
+            **make_request_args,
+        )
 
         # Advance so the save loop occurs
         self.reactor.advance(100)
diff --git a/tests/storage/test_event_metrics.py b/tests/storage/test_event_metrics.py
index 3957471f3f..7691f2d790 100644
--- a/tests/storage/test_event_metrics.py
+++ b/tests/storage/test_event_metrics.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 from synapse.metrics import REGISTRY, generate_latest
-from synapse.types import Requester, UserID
+from synapse.types import UserID, create_requester
 
 from tests.unittest import HomeserverTestCase
 
@@ -27,7 +27,7 @@ class ExtremStatisticsTestCase(HomeserverTestCase):
         room_creator = self.hs.get_room_creation_handler()
 
         user = UserID("alice", "test")
-        requester = Requester(user, None, False, False, None, None)
+        requester = create_requester(user)
 
         # Real events, forward extremities
         events = [(3, 2), (6, 2), (4, 6)]
diff --git a/tests/storage/test_id_generators.py b/tests/storage/test_id_generators.py
index 392b08832b..cc0612cf65 100644
--- a/tests/storage/test_id_generators.py
+++ b/tests/storage/test_id_generators.py
@@ -199,10 +199,17 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
         first_id_gen = self._create_id_generator("first", writers=["first", "second"])
         second_id_gen = self._create_id_generator("second", writers=["first", "second"])
 
-        self.assertEqual(first_id_gen.get_positions(), {"first": 3, "second": 7})
-        self.assertEqual(first_id_gen.get_current_token_for_writer("first"), 3)
+        # The first ID gen will notice that it can advance its token to 7 as it
+        # has no in progress writes...
+        self.assertEqual(first_id_gen.get_positions(), {"first": 7, "second": 7})
+        self.assertEqual(first_id_gen.get_current_token_for_writer("first"), 7)
         self.assertEqual(first_id_gen.get_current_token_for_writer("second"), 7)
 
+        # ... but the second ID gen doesn't know that.
+        self.assertEqual(second_id_gen.get_positions(), {"first": 3, "second": 7})
+        self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 3)
+        self.assertEqual(second_id_gen.get_current_token_for_writer("second"), 7)
+
         # Try allocating a new ID gen and check that we only see position
         # advanced after we leave the context manager.
 
@@ -211,7 +218,7 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
                 self.assertEqual(stream_id, 8)
 
                 self.assertEqual(
-                    first_id_gen.get_positions(), {"first": 3, "second": 7}
+                    first_id_gen.get_positions(), {"first": 7, "second": 7}
                 )
 
         self.get_success(_get_next_async())
@@ -279,7 +286,7 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
         self._insert_row_with_id("first", 3)
         self._insert_row_with_id("second", 5)
 
-        id_gen = self._create_id_generator("first", writers=["first", "second"])
+        id_gen = self._create_id_generator("worker", writers=["first", "second"])
 
         self.assertEqual(id_gen.get_positions(), {"first": 3, "second": 5})
 
@@ -319,14 +326,14 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
 
         id_gen = self._create_id_generator("first", writers=["first", "second"])
 
-        self.assertEqual(id_gen.get_positions(), {"first": 3, "second": 5})
+        self.assertEqual(id_gen.get_positions(), {"first": 5, "second": 5})
 
-        self.assertEqual(id_gen.get_persisted_upto_position(), 3)
+        self.assertEqual(id_gen.get_persisted_upto_position(), 5)
 
         async def _get_next_async():
             async with id_gen.get_next() as stream_id:
                 self.assertEqual(stream_id, 6)
-                self.assertEqual(id_gen.get_persisted_upto_position(), 3)
+                self.assertEqual(id_gen.get_persisted_upto_position(), 5)
 
         self.get_success(_get_next_async())
 
@@ -388,7 +395,7 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
         self._insert_row_with_id("second", 5)
 
         # Initial config has two writers
-        id_gen = self._create_id_generator("first", writers=["first", "second"])
+        id_gen = self._create_id_generator("worker", writers=["first", "second"])
         self.assertEqual(id_gen.get_persisted_upto_position(), 3)
         self.assertEqual(id_gen.get_current_token_for_writer("first"), 3)
         self.assertEqual(id_gen.get_current_token_for_writer("second"), 5)
@@ -568,7 +575,7 @@ class BackwardsMultiWriterIdGeneratorTestCase(HomeserverTestCase):
 
         self.get_success(_get_next_async2())
 
-        self.assertEqual(id_gen_1.get_positions(), {"first": -1, "second": -2})
+        self.assertEqual(id_gen_1.get_positions(), {"first": -2, "second": -2})
         self.assertEqual(id_gen_2.get_positions(), {"first": -1, "second": -2})
         self.assertEqual(id_gen_1.get_persisted_upto_position(), -2)
         self.assertEqual(id_gen_2.get_persisted_upto_position(), -2)
diff --git a/tests/storage/test_redaction.py b/tests/storage/test_redaction.py
index 1ea35d60c1..d4f9e809db 100644
--- a/tests/storage/test_redaction.py
+++ b/tests/storage/test_redaction.py
@@ -236,9 +236,9 @@ class RedactionTestCase(unittest.HomeserverTestCase):
                 self._event_id = event_id
 
             @defer.inlineCallbacks
-            def build(self, prev_event_ids):
+            def build(self, prev_event_ids, auth_event_ids):
                 built_event = yield defer.ensureDeferred(
-                    self._base_builder.build(prev_event_ids)
+                    self._base_builder.build(prev_event_ids, auth_event_ids)
                 )
 
                 built_event._event_id = self._event_id
diff --git a/tests/storage/test_registration.py b/tests/storage/test_registration.py
index 6b582771fe..c8c7a90e5d 100644
--- a/tests/storage/test_registration.py
+++ b/tests/storage/test_registration.py
@@ -69,11 +69,9 @@ class RegistrationStoreTestCase(unittest.TestCase):
             self.store.get_user_by_access_token(self.tokens[1])
         )
 
-        self.assertDictContainsSubset(
-            {"name": self.user_id, "device_id": self.device_id}, result
-        )
-
-        self.assertTrue("token_id" in result)
+        self.assertEqual(result.user_id, self.user_id)
+        self.assertEqual(result.device_id, self.device_id)
+        self.assertIsNotNone(result.token_id)
 
     @defer.inlineCallbacks
     def test_user_delete_access_tokens(self):
@@ -105,7 +103,7 @@ class RegistrationStoreTestCase(unittest.TestCase):
         user = yield defer.ensureDeferred(
             self.store.get_user_by_access_token(self.tokens[0])
         )
-        self.assertEqual(self.user_id, user["name"])
+        self.assertEqual(self.user_id, user.user_id)
 
         # now delete the rest
         yield defer.ensureDeferred(self.store.user_delete_access_tokens(self.user_id))
diff --git a/tests/storage/test_roommember.py b/tests/storage/test_roommember.py
index 12ccc1f53e..ff972daeaa 100644
--- a/tests/storage/test_roommember.py
+++ b/tests/storage/test_roommember.py
@@ -19,7 +19,7 @@ from unittest.mock import Mock
 from synapse.api.constants import Membership
 from synapse.rest.admin import register_servlets_for_client_rest_resource
 from synapse.rest.client.v1 import login, room
-from synapse.types import Requester, UserID
+from synapse.types import UserID, create_requester
 
 from tests import unittest
 from tests.test_utils import event_injection
@@ -187,7 +187,7 @@ class CurrentStateMembershipUpdateTestCase(unittest.HomeserverTestCase):
 
         # Now let's create a room, which will insert a membership
         user = UserID("alice", "test")
-        requester = Requester(user, None, False, False, None, None)
+        requester = create_requester(user)
         self.get_success(self.room_creator.create_room(requester, {}))
 
         # Register the background update to run again.
diff --git a/tests/test_federation.py b/tests/test_federation.py
index 27a7fc9ed7..1ce4ea3a01 100644
--- a/tests/test_federation.py
+++ b/tests/test_federation.py
@@ -20,7 +20,7 @@ from twisted.internet.defer import succeed
 from synapse.api.errors import FederationError
 from synapse.events import make_event_from_dict
 from synapse.logging.context import LoggingContext
-from synapse.types import Requester, UserID
+from synapse.types import UserID, create_requester
 from synapse.util import Clock
 from synapse.util.retryutils import NotRetryingDestination
 
@@ -43,7 +43,7 @@ class MessageAcceptTests(unittest.HomeserverTestCase):
         )
 
         user_id = UserID("us", "test")
-        our_user = Requester(user_id, None, False, False, None, None)
+        our_user = create_requester(user_id)
         room_creator = self.homeserver.get_room_creation_handler()
         self.room_id = self.get_success(
             room_creator.create_room(
@@ -75,7 +75,7 @@ class MessageAcceptTests(unittest.HomeserverTestCase):
             }
         )
 
-        self.handler = self.homeserver.get_handlers().federation_handler
+        self.handler = self.homeserver.get_federation_handler()
         self.handler.do_auth = lambda origin, event, context, auth_events: succeed(
             context
         )
diff --git a/tests/test_mau.py b/tests/test_mau.py
index 654a6fa42d..c5ec6396a7 100644
--- a/tests/test_mau.py
+++ b/tests/test_mau.py
@@ -202,7 +202,6 @@ class TestMauLimit(unittest.HomeserverTestCase):
         )
 
         request, channel = self.make_request("POST", "/register", request_data)
-        self.render(request)
 
         if channel.code != 200:
             raise HttpResponseException(
@@ -215,7 +214,6 @@ class TestMauLimit(unittest.HomeserverTestCase):
 
     def do_sync_for_user(self, token):
         request, channel = self.make_request("GET", "/sync", access_token=token)
-        self.render(request)
 
         if channel.code != 200:
             raise HttpResponseException(
diff --git a/tests/test_metrics.py b/tests/test_metrics.py
index f5f63d8ed6..759e4cd048 100644
--- a/tests/test_metrics.py
+++ b/tests/test_metrics.py
@@ -15,7 +15,7 @@
 # limitations under the License.
 
 from synapse.metrics import REGISTRY, InFlightGauge, generate_latest
-from synapse.util.caches.descriptors import Cache
+from synapse.util.caches.deferred_cache import DeferredCache
 
 from tests import unittest
 
@@ -138,7 +138,7 @@ class CacheMetricsTests(unittest.HomeserverTestCase):
         Caches produce metrics reflecting their state when scraped.
         """
         CACHE_NAME = "cache_metrics_test_fgjkbdfg"
-        cache = Cache(CACHE_NAME, max_entries=777)
+        cache = DeferredCache(CACHE_NAME, max_entries=777)
 
         items = {
             x.split(b"{")[0].decode("ascii"): x.split(b" ")[1].decode("ascii")
diff --git a/tests/test_phone_home.py b/tests/test_phone_home.py
index 7657bddea5..e7aed092c2 100644
--- a/tests/test_phone_home.py
+++ b/tests/test_phone_home.py
@@ -17,7 +17,7 @@ import resource
 
 import mock
 
-from synapse.app.homeserver import phone_stats_home
+from synapse.app.phone_stats_home import phone_stats_home
 
 from tests.unittest import HomeserverTestCase
 
diff --git a/tests/test_server.py b/tests/test_server.py
index 655c918a15..c387a85f2e 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -26,9 +26,9 @@ from synapse.util import Clock
 
 from tests import unittest
 from tests.server import (
+    FakeSite,
     ThreadedMemoryReactorClock,
     make_request,
-    render,
     setup_test_homeserver,
 )
 
@@ -62,9 +62,8 @@ class JsonResourceTests(unittest.TestCase):
         )
 
         request, channel = make_request(
-            self.reactor, b"GET", b"/_matrix/foo/%E2%98%83?a=%E2%98%83"
+            self.reactor, FakeSite(res), b"GET", b"/_matrix/foo/%E2%98%83?a=%E2%98%83"
         )
-        render(request, res, self.reactor)
 
         self.assertEqual(request.args, {b"a": ["\N{SNOWMAN}".encode("utf8")]})
         self.assertEqual(got_kwargs, {"room_id": "\N{SNOWMAN}"})
@@ -83,8 +82,7 @@ class JsonResourceTests(unittest.TestCase):
             "GET", [re.compile("^/_matrix/foo$")], _callback, "test_servlet"
         )
 
-        request, channel = make_request(self.reactor, b"GET", b"/_matrix/foo")
-        render(request, res, self.reactor)
+        _, channel = make_request(self.reactor, FakeSite(res), b"GET", b"/_matrix/foo")
 
         self.assertEqual(channel.result["code"], b"500")
 
@@ -108,8 +106,7 @@ class JsonResourceTests(unittest.TestCase):
             "GET", [re.compile("^/_matrix/foo$")], _callback, "test_servlet"
         )
 
-        request, channel = make_request(self.reactor, b"GET", b"/_matrix/foo")
-        render(request, res, self.reactor)
+        _, channel = make_request(self.reactor, FakeSite(res), b"GET", b"/_matrix/foo")
 
         self.assertEqual(channel.result["code"], b"500")
 
@@ -127,8 +124,7 @@ class JsonResourceTests(unittest.TestCase):
             "GET", [re.compile("^/_matrix/foo$")], _callback, "test_servlet"
         )
 
-        request, channel = make_request(self.reactor, b"GET", b"/_matrix/foo")
-        render(request, res, self.reactor)
+        _, channel = make_request(self.reactor, FakeSite(res), b"GET", b"/_matrix/foo")
 
         self.assertEqual(channel.result["code"], b"403")
         self.assertEqual(channel.json_body["error"], "Forbidden!!one!")
@@ -150,8 +146,9 @@ class JsonResourceTests(unittest.TestCase):
             "GET", [re.compile("^/_matrix/foo$")], _callback, "test_servlet"
         )
 
-        request, channel = make_request(self.reactor, b"GET", b"/_matrix/foobar")
-        render(request, res, self.reactor)
+        _, channel = make_request(
+            self.reactor, FakeSite(res), b"GET", b"/_matrix/foobar"
+        )
 
         self.assertEqual(channel.result["code"], b"400")
         self.assertEqual(channel.json_body["error"], "Unrecognized request")
@@ -173,8 +170,7 @@ class JsonResourceTests(unittest.TestCase):
         )
 
         # The path was registered as GET, but this is a HEAD request.
-        request, channel = make_request(self.reactor, b"HEAD", b"/_matrix/foo")
-        render(request, res, self.reactor)
+        _, channel = make_request(self.reactor, FakeSite(res), b"HEAD", b"/_matrix/foo")
 
         self.assertEqual(channel.result["code"], b"200")
         self.assertNotIn("body", channel.result)
@@ -196,9 +192,6 @@ class OptionsResourceTests(unittest.TestCase):
 
     def _make_request(self, method, path):
         """Create a request from the method/path and return a channel with the response."""
-        request, channel = make_request(self.reactor, method, path, shorthand=False)
-        request.prepath = []  # This doesn't get set properly by make_request.
-
         # Create a site and query for the resource.
         site = SynapseSite(
             "test",
@@ -207,11 +200,9 @@ class OptionsResourceTests(unittest.TestCase):
             self.resource,
             "1.0",
         )
-        request.site = site
-        resource = site.getResourceFor(request)
 
-        # Finally, render the resource and return the channel.
-        render(request, resource, self.reactor)
+        # render the request and return the channel
+        _, channel = make_request(self.reactor, site, method, path, shorthand=False)
         return channel
 
     def test_unknown_options_request(self):
@@ -284,8 +275,7 @@ class WrapHtmlRequestHandlerTests(unittest.TestCase):
         res = WrapHtmlRequestHandlerTests.TestResource()
         res.callback = callback
 
-        request, channel = make_request(self.reactor, b"GET", b"/path")
-        render(request, res, self.reactor)
+        _, channel = make_request(self.reactor, FakeSite(res), b"GET", b"/path")
 
         self.assertEqual(channel.result["code"], b"200")
         body = channel.result["body"]
@@ -303,8 +293,7 @@ class WrapHtmlRequestHandlerTests(unittest.TestCase):
         res = WrapHtmlRequestHandlerTests.TestResource()
         res.callback = callback
 
-        request, channel = make_request(self.reactor, b"GET", b"/path")
-        render(request, res, self.reactor)
+        _, channel = make_request(self.reactor, FakeSite(res), b"GET", b"/path")
 
         self.assertEqual(channel.result["code"], b"301")
         headers = channel.result["headers"]
@@ -325,8 +314,7 @@ class WrapHtmlRequestHandlerTests(unittest.TestCase):
         res = WrapHtmlRequestHandlerTests.TestResource()
         res.callback = callback
 
-        request, channel = make_request(self.reactor, b"GET", b"/path")
-        render(request, res, self.reactor)
+        _, channel = make_request(self.reactor, FakeSite(res), b"GET", b"/path")
 
         self.assertEqual(channel.result["code"], b"304")
         headers = channel.result["headers"]
@@ -345,8 +333,7 @@ class WrapHtmlRequestHandlerTests(unittest.TestCase):
         res = WrapHtmlRequestHandlerTests.TestResource()
         res.callback = callback
 
-        request, channel = make_request(self.reactor, b"HEAD", b"/path")
-        render(request, res, self.reactor)
+        _, channel = make_request(self.reactor, FakeSite(res), b"HEAD", b"/path")
 
         self.assertEqual(channel.result["code"], b"200")
         self.assertNotIn("body", channel.result)
diff --git a/tests/test_state.py b/tests/test_state.py
index 80b0ccbc40..6227a3ba95 100644
--- a/tests/test_state.py
+++ b/tests/test_state.py
@@ -169,6 +169,7 @@ class StateTestCase(unittest.TestCase):
                 "get_state_handler",
                 "get_clock",
                 "get_state_resolution_handler",
+                "hostname",
             ]
         )
         hs.config = default_config("tesths", True)
diff --git a/tests/test_terms_auth.py b/tests/test_terms_auth.py
index b89798336c..71580b454d 100644
--- a/tests/test_terms_auth.py
+++ b/tests/test_terms_auth.py
@@ -54,7 +54,6 @@ class TermsTestCase(unittest.HomeserverTestCase):
         # Do a UI auth request
         request_data = json.dumps({"username": "kermit", "password": "monkey"})
         request, channel = self.make_request(b"POST", self.url, request_data)
-        self.render(request)
 
         self.assertEquals(channel.result["code"], b"401", channel.result)
 
@@ -98,7 +97,6 @@ class TermsTestCase(unittest.HomeserverTestCase):
         self.registration_handler.check_username = Mock(return_value=True)
 
         request, channel = self.make_request(b"POST", self.url, request_data)
-        self.render(request)
 
         # We don't bother checking that the response is correct - we'll leave that to
         # other tests. We just want to make sure we're on the right path.
@@ -116,7 +114,6 @@ class TermsTestCase(unittest.HomeserverTestCase):
             }
         )
         request, channel = self.make_request(b"POST", self.url, request_data)
-        self.render(request)
 
         # We're interested in getting a response that looks like a successful
         # registration, not so much that the details are exactly what we want.
diff --git a/tests/test_utils/__init__.py b/tests/test_utils/__init__.py
index a298cc0fd3..d232b72264 100644
--- a/tests/test_utils/__init__.py
+++ b/tests/test_utils/__init__.py
@@ -17,8 +17,10 @@
 """
 Utilities for running the unit tests
 """
+import sys
+import warnings
 from asyncio import Future
-from typing import Any, Awaitable, TypeVar
+from typing import Any, Awaitable, Callable, TypeVar
 
 TV = TypeVar("TV")
 
@@ -48,3 +50,33 @@ def make_awaitable(result: Any) -> Awaitable[Any]:
     future = Future()  # type: ignore
     future.set_result(result)
     return future
+
+
+def setup_awaitable_errors() -> Callable[[], None]:
+    """
+    Convert warnings from a non-awaited coroutines into errors.
+    """
+    warnings.simplefilter("error", RuntimeWarning)
+
+    # unraisablehook was added in Python 3.8.
+    if not hasattr(sys, "unraisablehook"):
+        return lambda: None
+
+    # State shared between unraisablehook and check_for_unraisable_exceptions.
+    unraisable_exceptions = []
+    orig_unraisablehook = sys.unraisablehook  # type: ignore
+
+    def unraisablehook(unraisable):
+        unraisable_exceptions.append(unraisable.exc_value)
+
+    def cleanup():
+        """
+        A method to be used as a clean-up that fails a test-case if there are any new unraisable exceptions.
+        """
+        sys.unraisablehook = orig_unraisablehook  # type: ignore
+        if unraisable_exceptions:
+            raise unraisable_exceptions.pop()
+
+    sys.unraisablehook = unraisablehook  # type: ignore
+
+    return cleanup
diff --git a/tests/test_utils/event_injection.py b/tests/test_utils/event_injection.py
index e93aa84405..c3c4a93e1f 100644
--- a/tests/test_utils/event_injection.py
+++ b/tests/test_utils/event_injection.py
@@ -50,7 +50,7 @@ async def inject_member_event(
         sender=sender,
         state_key=target,
         content=content,
-        **kwargs
+        **kwargs,
     )
 
 
diff --git a/tests/unittest.py b/tests/unittest.py
index e654c0442d..a9d59e31f7 100644
--- a/tests/unittest.py
+++ b/tests/unittest.py
@@ -20,7 +20,7 @@ import hmac
 import inspect
 import logging
 import time
-from typing import Optional, Tuple, Type, TypeVar, Union
+from typing import Optional, Tuple, Type, TypeVar, Union, overload
 
 from mock import Mock, patch
 
@@ -30,6 +30,7 @@ from twisted.internet.defer import Deferred, ensureDeferred, succeed
 from twisted.python.failure import Failure
 from twisted.python.threadpool import ThreadPool
 from twisted.trial import unittest
+from twisted.web.resource import Resource
 
 from synapse.api.constants import EventTypes, Membership
 from synapse.config.homeserver import HomeServerConfig
@@ -44,17 +45,11 @@ from synapse.logging.context import (
     set_current_context,
 )
 from synapse.server import HomeServer
-from synapse.types import Requester, UserID, create_requester
+from synapse.types import UserID, create_requester
 from synapse.util.ratelimitutils import FederationRateLimiter
 
-from tests.server import (
-    FakeChannel,
-    get_clock,
-    make_request,
-    render,
-    setup_test_homeserver,
-)
-from tests.test_utils import event_injection
+from tests.server import FakeChannel, get_clock, make_request, setup_test_homeserver
+from tests.test_utils import event_injection, setup_awaitable_errors
 from tests.test_utils.logging_setup import setup_logging
 from tests.utils import default_config, setupdb
 
@@ -119,6 +114,10 @@ class TestCase(unittest.TestCase):
 
                 logging.getLogger().setLevel(level)
 
+            # Trial messes with the warnings configuration, thus this has to be
+            # done in the context of an individual TestCase.
+            self.addCleanup(setup_awaitable_errors())
+
             return orig()
 
         @around(self)
@@ -235,13 +234,11 @@ class HomeserverTestCase(TestCase):
         if not isinstance(self.hs, HomeServer):
             raise Exception("A homeserver wasn't returned, but %r" % (self.hs,))
 
-        # Register the resources
-        self.resource = self.create_test_json_resource()
-
-        # create a site to wrap the resource.
+        # create the root resource, and a site to wrap it.
+        self.resource = self.create_test_resource()
         self.site = SynapseSite(
             logger_name="synapse.access.http.fake",
-            site_tag="test",
+            site_tag=self.hs.config.server.server_name,
             config=self.hs.config.server.listeners[0],
             resource=self.resource,
             server_version_string="1",
@@ -249,22 +246,29 @@ class HomeserverTestCase(TestCase):
 
         from tests.rest.client.v1.utils import RestHelper
 
-        self.helper = RestHelper(self.hs, self.resource, getattr(self, "user_id", None))
+        self.helper = RestHelper(self.hs, self.site, getattr(self, "user_id", None))
 
         if hasattr(self, "user_id"):
             if self.hijack_auth:
 
+                # We need a valid token ID to satisfy foreign key constraints.
+                token_id = self.get_success(
+                    self.hs.get_datastore().add_access_token_to_user(
+                        self.helper.auth_user_id, "some_fake_token", None, None,
+                    )
+                )
+
                 async def get_user_by_access_token(token=None, allow_guest=False):
                     return {
                         "user": UserID.from_string(self.helper.auth_user_id),
-                        "token_id": 1,
+                        "token_id": token_id,
                         "is_guest": False,
                     }
 
                 async def get_user_by_req(request, allow_guest=False, rights="access"):
                     return create_requester(
                         UserID.from_string(self.helper.auth_user_id),
-                        1,
+                        token_id,
                         False,
                         False,
                         None,
@@ -312,15 +316,12 @@ class HomeserverTestCase(TestCase):
         hs = self.setup_test_homeserver()
         return hs
 
-    def create_test_json_resource(self):
+    def create_test_resource(self) -> Resource:
         """
-        Create a test JsonResource, with the relevant servlets registerd to it
+        Create a the root resource for the test server.
 
-        The default implementation calls each function in `servlets` to do the
-        registration.
-
-        Returns:
-            JsonResource:
+        The default implementation creates a JsonResource and calls each function in
+        `servlets` to register servletes against it
         """
         resource = JsonResource(self.hs)
 
@@ -357,6 +358,24 @@ class HomeserverTestCase(TestCase):
         Function to optionally be overridden in subclasses.
         """
 
+    # Annoyingly mypy doesn't seem to pick up the fact that T is SynapseRequest
+    # when the `request` arg isn't given, so we define an explicit override to
+    # cover that case.
+    @overload
+    def make_request(
+        self,
+        method: Union[bytes, str],
+        path: Union[bytes, str],
+        content: Union[bytes, dict] = b"",
+        access_token: Optional[str] = None,
+        shorthand: bool = True,
+        federation_auth_origin: str = None,
+        content_is_form: bool = False,
+        await_result: bool = True,
+    ) -> Tuple[SynapseRequest, FakeChannel]:
+        ...
+
+    @overload
     def make_request(
         self,
         method: Union[bytes, str],
@@ -367,6 +386,21 @@ class HomeserverTestCase(TestCase):
         shorthand: bool = True,
         federation_auth_origin: str = None,
         content_is_form: bool = False,
+        await_result: bool = True,
+    ) -> Tuple[T, FakeChannel]:
+        ...
+
+    def make_request(
+        self,
+        method: Union[bytes, str],
+        path: Union[bytes, str],
+        content: Union[bytes, dict] = b"",
+        access_token: Optional[str] = None,
+        request: Type[T] = SynapseRequest,
+        shorthand: bool = True,
+        federation_auth_origin: str = None,
+        content_is_form: bool = False,
+        await_result: bool = True,
     ) -> Tuple[T, FakeChannel]:
         """
         Create a SynapseRequest at the path using the method and containing the
@@ -385,14 +419,16 @@ class HomeserverTestCase(TestCase):
             content_is_form: Whether the content is URL encoded form data. Adds the
                 'Content-Type': 'application/x-www-form-urlencoded' header.
 
+            await_result: whether to wait for the request to complete rendering. If
+                 true (the default), will pump the test reactor until the the renderer
+                 tells the channel the request is finished.
+
         Returns:
             Tuple[synapse.http.site.SynapseRequest, channel]
         """
-        if isinstance(content, dict):
-            content = json.dumps(content).encode("utf8")
-
         return make_request(
             self.reactor,
+            self.site,
             method,
             path,
             content,
@@ -401,18 +437,9 @@ class HomeserverTestCase(TestCase):
             shorthand,
             federation_auth_origin,
             content_is_form,
+            await_result,
         )
 
-    def render(self, request):
-        """
-        Render a request against the resources registered by the test class's
-        servlets.
-
-        Args:
-            request (synapse.http.site.SynapseRequest): The request to render.
-        """
-        render(request, self.resource, self.reactor)
-
     def setup_test_homeserver(self, *args, **kwargs):
         """
         Set up the test homeserver, meant to be called by the overridable
@@ -505,24 +532,29 @@ class HomeserverTestCase(TestCase):
 
         return result
 
-    def register_user(self, username, password, admin=False):
+    def register_user(
+        self,
+        username: str,
+        password: str,
+        admin: Optional[bool] = False,
+        displayname: Optional[str] = None,
+    ) -> str:
         """
         Register a user. Requires the Admin API be registered.
 
         Args:
-            username (bytes/unicode): The user part of the new user.
-            password (bytes/unicode): The password of the new user.
-            admin (bool): Whether the user should be created as an admin
-            or not.
+            username: The user part of the new user.
+            password: The password of the new user.
+            admin: Whether the user should be created as an admin or not.
+            displayname: The displayname of the new user.
 
         Returns:
-            The MXID of the new user (unicode).
+            The MXID of the new user.
         """
         self.hs.config.registration_shared_secret = "shared"
 
         # Create the user
-        request, channel = self.make_request("GET", "/_matrix/client/r0/admin/register")
-        self.render(request)
+        request, channel = self.make_request("GET", "/_synapse/admin/v1/register")
         self.assertEqual(channel.code, 200, msg=channel.result)
         nonce = channel.json_body["nonce"]
 
@@ -540,6 +572,7 @@ class HomeserverTestCase(TestCase):
             {
                 "nonce": nonce,
                 "username": username,
+                "displayname": displayname,
                 "password": password,
                 "admin": admin,
                 "mac": want_mac,
@@ -547,9 +580,8 @@ class HomeserverTestCase(TestCase):
             }
         )
         request, channel = self.make_request(
-            "POST", "/_matrix/client/r0/admin/register", body.encode("utf8")
+            "POST", "/_synapse/admin/v1/register", body.encode("utf8")
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.json_body)
 
         user_id = channel.json_body["user_id"]
@@ -568,7 +600,6 @@ class HomeserverTestCase(TestCase):
         request, channel = self.make_request(
             "POST", "/_matrix/client/r0/login", json.dumps(body).encode("utf8")
         )
-        self.render(request)
         self.assertEqual(channel.code, 200, channel.result)
 
         access_token = channel.json_body["access_token"]
@@ -590,7 +621,7 @@ class HomeserverTestCase(TestCase):
         """
         event_creator = self.hs.get_event_creation_handler()
         secrets = self.hs.get_secrets()
-        requester = Requester(user, None, False, False, None, None)
+        requester = create_requester(user)
 
         event, context = self.get_success(
             event_creator.create_event(
@@ -608,7 +639,9 @@ class HomeserverTestCase(TestCase):
         if soft_failed:
             event.internal_metadata.soft_failed = True
 
-        self.get_success(event_creator.send_nonmember_event(requester, event, context))
+        self.get_success(
+            event_creator.handle_new_client_event(requester, event, context)
+        )
 
         return event.event_id
 
@@ -635,7 +668,6 @@ class HomeserverTestCase(TestCase):
         request, channel = self.make_request(
             "POST", "/_matrix/client/r0/login", json.dumps(body).encode("utf8")
         )
-        self.render(request)
         self.assertEqual(channel.code, 403, channel.result)
 
     def inject_room_member(self, room: str, user: str, membership: Membership) -> None:
diff --git a/tests/util/caches/test_deferred_cache.py b/tests/util/caches/test_deferred_cache.py
new file mode 100644
index 0000000000..dadfabd46d
--- /dev/null
+++ b/tests/util/caches/test_deferred_cache.py
@@ -0,0 +1,251 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from functools import partial
+
+from twisted.internet import defer
+
+from synapse.util.caches.deferred_cache import DeferredCache
+
+from tests.unittest import TestCase
+
+
+class DeferredCacheTestCase(TestCase):
+    def test_empty(self):
+        cache = DeferredCache("test")
+        failed = False
+        try:
+            cache.get("foo")
+        except KeyError:
+            failed = True
+
+        self.assertTrue(failed)
+
+    def test_hit(self):
+        cache = DeferredCache("test")
+        cache.prefill("foo", 123)
+
+        self.assertEquals(self.successResultOf(cache.get("foo")), 123)
+
+    def test_hit_deferred(self):
+        cache = DeferredCache("test")
+        origin_d = defer.Deferred()
+        set_d = cache.set("k1", origin_d)
+
+        # get should return an incomplete deferred
+        get_d = cache.get("k1")
+        self.assertFalse(get_d.called)
+
+        # add a callback that will make sure that the set_d gets called before the get_d
+        def check1(r):
+            self.assertTrue(set_d.called)
+            return r
+
+        # TODO: Actually ObservableDeferred *doesn't* run its tests in order on py3.8.
+        #   maybe we should fix that?
+        # get_d.addCallback(check1)
+
+        # now fire off all the deferreds
+        origin_d.callback(99)
+        self.assertEqual(self.successResultOf(origin_d), 99)
+        self.assertEqual(self.successResultOf(set_d), 99)
+        self.assertEqual(self.successResultOf(get_d), 99)
+
+    def test_callbacks(self):
+        """Invalidation callbacks are called at the right time"""
+        cache = DeferredCache("test")
+        callbacks = set()
+
+        # start with an entry, with a callback
+        cache.prefill("k1", 10, callback=lambda: callbacks.add("prefill"))
+
+        # now replace that entry with a pending result
+        origin_d = defer.Deferred()
+        set_d = cache.set("k1", origin_d, callback=lambda: callbacks.add("set"))
+
+        # ... and also make a get request
+        get_d = cache.get("k1", callback=lambda: callbacks.add("get"))
+
+        # we don't expect the invalidation callback for the original value to have
+        # been called yet, even though get() will now return a different result.
+        # I'm not sure if that is by design or not.
+        self.assertEqual(callbacks, set())
+
+        # now fire off all the deferreds
+        origin_d.callback(20)
+        self.assertEqual(self.successResultOf(set_d), 20)
+        self.assertEqual(self.successResultOf(get_d), 20)
+
+        # now the original invalidation callback should have been called, but none of
+        # the others
+        self.assertEqual(callbacks, {"prefill"})
+        callbacks.clear()
+
+        # another update should invalidate both the previous results
+        cache.prefill("k1", 30)
+        self.assertEqual(callbacks, {"set", "get"})
+
+    def test_set_fail(self):
+        cache = DeferredCache("test")
+        callbacks = set()
+
+        # start with an entry, with a callback
+        cache.prefill("k1", 10, callback=lambda: callbacks.add("prefill"))
+
+        # now replace that entry with a pending result
+        origin_d = defer.Deferred()
+        set_d = cache.set("k1", origin_d, callback=lambda: callbacks.add("set"))
+
+        # ... and also make a get request
+        get_d = cache.get("k1", callback=lambda: callbacks.add("get"))
+
+        # none of the callbacks should have been called yet
+        self.assertEqual(callbacks, set())
+
+        # oh noes! fails!
+        e = Exception("oops")
+        origin_d.errback(e)
+        self.assertIs(self.failureResultOf(set_d, Exception).value, e)
+        self.assertIs(self.failureResultOf(get_d, Exception).value, e)
+
+        # the callbacks for the failed requests should have been called.
+        # I'm not sure if this is deliberate or not.
+        self.assertEqual(callbacks, {"get", "set"})
+        callbacks.clear()
+
+        # the old value should still be returned now?
+        get_d2 = cache.get("k1", callback=lambda: callbacks.add("get2"))
+        self.assertEqual(self.successResultOf(get_d2), 10)
+
+        # replacing the value now should run the callbacks for those requests
+        # which got the original result
+        cache.prefill("k1", 30)
+        self.assertEqual(callbacks, {"prefill", "get2"})
+
+    def test_get_immediate(self):
+        cache = DeferredCache("test")
+        d1 = defer.Deferred()
+        cache.set("key1", d1)
+
+        # get_immediate should return default
+        v = cache.get_immediate("key1", 1)
+        self.assertEqual(v, 1)
+
+        # now complete the set
+        d1.callback(2)
+
+        # get_immediate should return result
+        v = cache.get_immediate("key1", 1)
+        self.assertEqual(v, 2)
+
+    def test_invalidate(self):
+        cache = DeferredCache("test")
+        cache.prefill(("foo",), 123)
+        cache.invalidate(("foo",))
+
+        failed = False
+        try:
+            cache.get(("foo",))
+        except KeyError:
+            failed = True
+
+        self.assertTrue(failed)
+
+    def test_invalidate_all(self):
+        cache = DeferredCache("testcache")
+
+        callback_record = [False, False]
+
+        def record_callback(idx):
+            callback_record[idx] = True
+
+        # add a couple of pending entries
+        d1 = defer.Deferred()
+        cache.set("key1", d1, partial(record_callback, 0))
+
+        d2 = defer.Deferred()
+        cache.set("key2", d2, partial(record_callback, 1))
+
+        # lookup should return pending deferreds
+        self.assertFalse(cache.get("key1").called)
+        self.assertFalse(cache.get("key2").called)
+
+        # let one of the lookups complete
+        d2.callback("result2")
+
+        # now the cache will return a completed deferred
+        self.assertEqual(self.successResultOf(cache.get("key2")), "result2")
+
+        # now do the invalidation
+        cache.invalidate_all()
+
+        # lookup should fail
+        with self.assertRaises(KeyError):
+            cache.get("key1")
+        with self.assertRaises(KeyError):
+            cache.get("key2")
+
+        # both callbacks should have been callbacked
+        self.assertTrue(callback_record[0], "Invalidation callback for key1 not called")
+        self.assertTrue(callback_record[1], "Invalidation callback for key2 not called")
+
+        # letting the other lookup complete should do nothing
+        d1.callback("result1")
+        with self.assertRaises(KeyError):
+            cache.get("key1", None)
+
+    def test_eviction(self):
+        cache = DeferredCache(
+            "test", max_entries=2, apply_cache_factor_from_config=False
+        )
+
+        cache.prefill(1, "one")
+        cache.prefill(2, "two")
+        cache.prefill(3, "three")  # 1 will be evicted
+
+        failed = False
+        try:
+            cache.get(1)
+        except KeyError:
+            failed = True
+
+        self.assertTrue(failed)
+
+        cache.get(2)
+        cache.get(3)
+
+    def test_eviction_lru(self):
+        cache = DeferredCache(
+            "test", max_entries=2, apply_cache_factor_from_config=False
+        )
+
+        cache.prefill(1, "one")
+        cache.prefill(2, "two")
+
+        # Now access 1 again, thus causing 2 to be least-recently used
+        cache.get(1)
+
+        cache.prefill(3, "three")
+
+        failed = False
+        try:
+            cache.get(2)
+        except KeyError:
+            failed = True
+
+        self.assertTrue(failed)
+
+        cache.get(1)
+        cache.get(3)
diff --git a/tests/util/caches/test_descriptors.py b/tests/util/caches/test_descriptors.py
index 677e925477..cf1e3203a4 100644
--- a/tests/util/caches/test_descriptors.py
+++ b/tests/util/caches/test_descriptors.py
@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from functools import partial
+from typing import Set
 
 import mock
 
@@ -29,62 +29,52 @@ from synapse.logging.context import (
     make_deferred_yieldable,
 )
 from synapse.util.caches import descriptors
-from synapse.util.caches.descriptors import cached
+from synapse.util.caches.descriptors import cached, lru_cache
 
 from tests import unittest
+from tests.test_utils import get_awaitable_result
 
 logger = logging.getLogger(__name__)
 
 
+class LruCacheDecoratorTestCase(unittest.TestCase):
+    def test_base(self):
+        class Cls:
+            def __init__(self):
+                self.mock = mock.Mock()
+
+            @lru_cache()
+            def fn(self, arg1, arg2):
+                return self.mock(arg1, arg2)
+
+        obj = Cls()
+        obj.mock.return_value = "fish"
+        r = obj.fn(1, 2)
+        self.assertEqual(r, "fish")
+        obj.mock.assert_called_once_with(1, 2)
+        obj.mock.reset_mock()
+
+        # a call with different params should call the mock again
+        obj.mock.return_value = "chips"
+        r = obj.fn(1, 3)
+        self.assertEqual(r, "chips")
+        obj.mock.assert_called_once_with(1, 3)
+        obj.mock.reset_mock()
+
+        # the two values should now be cached
+        r = obj.fn(1, 2)
+        self.assertEqual(r, "fish")
+        r = obj.fn(1, 3)
+        self.assertEqual(r, "chips")
+        obj.mock.assert_not_called()
+
+
 def run_on_reactor():
     d = defer.Deferred()
     reactor.callLater(0, d.callback, 0)
     return make_deferred_yieldable(d)
 
 
-class CacheTestCase(unittest.TestCase):
-    def test_invalidate_all(self):
-        cache = descriptors.Cache("testcache")
-
-        callback_record = [False, False]
-
-        def record_callback(idx):
-            callback_record[idx] = True
-
-        # add a couple of pending entries
-        d1 = defer.Deferred()
-        cache.set("key1", d1, partial(record_callback, 0))
-
-        d2 = defer.Deferred()
-        cache.set("key2", d2, partial(record_callback, 1))
-
-        # lookup should return observable deferreds
-        self.assertFalse(cache.get("key1").has_called())
-        self.assertFalse(cache.get("key2").has_called())
-
-        # let one of the lookups complete
-        d2.callback("result2")
-
-        # for now at least, the cache will return real results rather than an
-        # observabledeferred
-        self.assertEqual(cache.get("key2"), "result2")
-
-        # now do the invalidation
-        cache.invalidate_all()
-
-        # lookup should return none
-        self.assertIsNone(cache.get("key1", None))
-        self.assertIsNone(cache.get("key2", None))
-
-        # both callbacks should have been callbacked
-        self.assertTrue(callback_record[0], "Invalidation callback for key1 not called")
-        self.assertTrue(callback_record[1], "Invalidation callback for key2 not called")
-
-        # letting the other lookup complete should do nothing
-        d1.callback("result1")
-        self.assertIsNone(cache.get("key1", None))
-
-
 class DescriptorTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def test_cache(self):
@@ -174,6 +164,57 @@ class DescriptorTestCase(unittest.TestCase):
         d = obj.fn(1)
         self.failureResultOf(d, SynapseError)
 
+    def test_cache_with_async_exception(self):
+        """The wrapped function returns a failure
+        """
+
+        class Cls:
+            result = None
+            call_count = 0
+
+            @cached()
+            def fn(self, arg1):
+                self.call_count += 1
+                return self.result
+
+        obj = Cls()
+        callbacks = set()  # type: Set[str]
+
+        # set off an asynchronous request
+        obj.result = origin_d = defer.Deferred()
+
+        d1 = obj.fn(1, on_invalidate=lambda: callbacks.add("d1"))
+        self.assertFalse(d1.called)
+
+        # a second request should also return a deferred, but should not call the
+        # function itself.
+        d2 = obj.fn(1, on_invalidate=lambda: callbacks.add("d2"))
+        self.assertFalse(d2.called)
+        self.assertEqual(obj.call_count, 1)
+
+        # no callbacks yet
+        self.assertEqual(callbacks, set())
+
+        # the original request fails
+        e = Exception("bzz")
+        origin_d.errback(e)
+
+        # ... which should cause the lookups to fail similarly
+        self.assertIs(self.failureResultOf(d1, Exception).value, e)
+        self.assertIs(self.failureResultOf(d2, Exception).value, e)
+
+        # ... and the callbacks to have been, uh, called.
+        self.assertEqual(callbacks, {"d1", "d2"})
+
+        # ... leaving the cache empty
+        self.assertEqual(len(obj.fn.cache.cache), 0)
+
+        # and a second call should work as normal
+        obj.result = defer.succeed(100)
+        d3 = obj.fn(1)
+        self.assertEqual(self.successResultOf(d3), 100)
+        self.assertEqual(obj.call_count, 2)
+
     def test_cache_logcontexts(self):
         """Check that logcontexts are set and restored correctly when
         using the cache."""
@@ -354,6 +395,260 @@ class DescriptorTestCase(unittest.TestCase):
         d = obj.fn(1)
         self.failureResultOf(d, SynapseError)
 
+    def test_invalidate_cascade(self):
+        """Invalidations should cascade up through cache contexts"""
+
+        class Cls:
+            @cached(cache_context=True)
+            async def func1(self, key, cache_context):
+                return await self.func2(key, on_invalidate=cache_context.invalidate)
+
+            @cached(cache_context=True)
+            async def func2(self, key, cache_context):
+                return self.func3(key, on_invalidate=cache_context.invalidate)
+
+            @lru_cache(cache_context=True)
+            def func3(self, key, cache_context):
+                self.invalidate = cache_context.invalidate
+                return 42
+
+        obj = Cls()
+
+        top_invalidate = mock.Mock()
+        r = get_awaitable_result(obj.func1("k1", on_invalidate=top_invalidate))
+        self.assertEqual(r, 42)
+        obj.invalidate()
+        top_invalidate.assert_called_once()
+
+
+class CacheDecoratorTestCase(unittest.HomeserverTestCase):
+    """More tests for @cached
+
+    The following is a set of tests that got lost in a different file for a while.
+
+    There are probably duplicates of the tests in DescriptorTestCase. Ideally the
+    duplicates would be removed and the two sets of classes combined.
+    """
+
+    @defer.inlineCallbacks
+    def test_passthrough(self):
+        class A:
+            @cached()
+            def func(self, key):
+                return key
+
+        a = A()
+
+        self.assertEquals((yield a.func("foo")), "foo")
+        self.assertEquals((yield a.func("bar")), "bar")
+
+    @defer.inlineCallbacks
+    def test_hit(self):
+        callcount = [0]
+
+        class A:
+            @cached()
+            def func(self, key):
+                callcount[0] += 1
+                return key
+
+        a = A()
+        yield a.func("foo")
+
+        self.assertEquals(callcount[0], 1)
+
+        self.assertEquals((yield a.func("foo")), "foo")
+        self.assertEquals(callcount[0], 1)
+
+    @defer.inlineCallbacks
+    def test_invalidate(self):
+        callcount = [0]
+
+        class A:
+            @cached()
+            def func(self, key):
+                callcount[0] += 1
+                return key
+
+        a = A()
+        yield a.func("foo")
+
+        self.assertEquals(callcount[0], 1)
+
+        a.func.invalidate(("foo",))
+
+        yield a.func("foo")
+
+        self.assertEquals(callcount[0], 2)
+
+    def test_invalidate_missing(self):
+        class A:
+            @cached()
+            def func(self, key):
+                return key
+
+        A().func.invalidate(("what",))
+
+    @defer.inlineCallbacks
+    def test_max_entries(self):
+        callcount = [0]
+
+        class A:
+            @cached(max_entries=10)
+            def func(self, key):
+                callcount[0] += 1
+                return key
+
+        a = A()
+
+        for k in range(0, 12):
+            yield a.func(k)
+
+        self.assertEquals(callcount[0], 12)
+
+        # There must have been at least 2 evictions, meaning if we calculate
+        # all 12 values again, we must get called at least 2 more times
+        for k in range(0, 12):
+            yield a.func(k)
+
+        self.assertTrue(
+            callcount[0] >= 14, msg="Expected callcount >= 14, got %d" % (callcount[0])
+        )
+
+    def test_prefill(self):
+        callcount = [0]
+
+        d = defer.succeed(123)
+
+        class A:
+            @cached()
+            def func(self, key):
+                callcount[0] += 1
+                return d
+
+        a = A()
+
+        a.func.prefill(("foo",), 456)
+
+        self.assertEquals(a.func("foo").result, 456)
+        self.assertEquals(callcount[0], 0)
+
+    @defer.inlineCallbacks
+    def test_invalidate_context(self):
+        callcount = [0]
+        callcount2 = [0]
+
+        class A:
+            @cached()
+            def func(self, key):
+                callcount[0] += 1
+                return key
+
+            @cached(cache_context=True)
+            def func2(self, key, cache_context):
+                callcount2[0] += 1
+                return self.func(key, on_invalidate=cache_context.invalidate)
+
+        a = A()
+        yield a.func2("foo")
+
+        self.assertEquals(callcount[0], 1)
+        self.assertEquals(callcount2[0], 1)
+
+        a.func.invalidate(("foo",))
+        yield a.func("foo")
+
+        self.assertEquals(callcount[0], 2)
+        self.assertEquals(callcount2[0], 1)
+
+        yield a.func2("foo")
+
+        self.assertEquals(callcount[0], 2)
+        self.assertEquals(callcount2[0], 2)
+
+    @defer.inlineCallbacks
+    def test_eviction_context(self):
+        callcount = [0]
+        callcount2 = [0]
+
+        class A:
+            @cached(max_entries=2)
+            def func(self, key):
+                callcount[0] += 1
+                return key
+
+            @cached(cache_context=True)
+            def func2(self, key, cache_context):
+                callcount2[0] += 1
+                return self.func(key, on_invalidate=cache_context.invalidate)
+
+        a = A()
+        yield a.func2("foo")
+        yield a.func2("foo2")
+
+        self.assertEquals(callcount[0], 2)
+        self.assertEquals(callcount2[0], 2)
+
+        yield a.func2("foo")
+        self.assertEquals(callcount[0], 2)
+        self.assertEquals(callcount2[0], 2)
+
+        yield a.func("foo3")
+
+        self.assertEquals(callcount[0], 3)
+        self.assertEquals(callcount2[0], 2)
+
+        yield a.func2("foo")
+
+        self.assertEquals(callcount[0], 4)
+        self.assertEquals(callcount2[0], 3)
+
+    @defer.inlineCallbacks
+    def test_double_get(self):
+        callcount = [0]
+        callcount2 = [0]
+
+        class A:
+            @cached()
+            def func(self, key):
+                callcount[0] += 1
+                return key
+
+            @cached(cache_context=True)
+            def func2(self, key, cache_context):
+                callcount2[0] += 1
+                return self.func(key, on_invalidate=cache_context.invalidate)
+
+        a = A()
+        a.func2.cache.cache = mock.Mock(wraps=a.func2.cache.cache)
+
+        yield a.func2("foo")
+
+        self.assertEquals(callcount[0], 1)
+        self.assertEquals(callcount2[0], 1)
+
+        a.func2.invalidate(("foo",))
+        self.assertEquals(a.func2.cache.cache.pop.call_count, 1)
+
+        yield a.func2("foo")
+        a.func2.invalidate(("foo",))
+        self.assertEquals(a.func2.cache.cache.pop.call_count, 2)
+
+        self.assertEquals(callcount[0], 1)
+        self.assertEquals(callcount2[0], 2)
+
+        a.func.invalidate(("foo",))
+        self.assertEquals(a.func2.cache.cache.pop.call_count, 3)
+        yield a.func("foo")
+
+        self.assertEquals(callcount[0], 2)
+        self.assertEquals(callcount2[0], 2)
+
+        yield a.func2("foo")
+
+        self.assertEquals(callcount[0], 2)
+        self.assertEquals(callcount2[0], 3)
+
 
 class CachedListDescriptorTestCase(unittest.TestCase):
     @defer.inlineCallbacks
diff --git a/tests/util/test_lrucache.py b/tests/util/test_lrucache.py
index 0adb2174af..a739a6aaaf 100644
--- a/tests/util/test_lrucache.py
+++ b/tests/util/test_lrucache.py
@@ -19,7 +19,8 @@ from mock import Mock
 from synapse.util.caches.lrucache import LruCache
 from synapse.util.caches.treecache import TreeCache
 
-from .. import unittest
+from tests import unittest
+from tests.unittest import override_config
 
 
 class LruCacheTestCase(unittest.HomeserverTestCase):
@@ -59,7 +60,7 @@ class LruCacheTestCase(unittest.HomeserverTestCase):
         self.assertEquals(cache.pop("key"), None)
 
     def test_del_multi(self):
-        cache = LruCache(4, 2, cache_type=TreeCache)
+        cache = LruCache(4, keylen=2, cache_type=TreeCache)
         cache[("animal", "cat")] = "mew"
         cache[("animal", "dog")] = "woof"
         cache[("vehicles", "car")] = "vroom"
@@ -83,6 +84,11 @@ class LruCacheTestCase(unittest.HomeserverTestCase):
         cache.clear()
         self.assertEquals(len(cache), 0)
 
+    @override_config({"caches": {"per_cache_factors": {"mycache": 10}}})
+    def test_special_size(self):
+        cache = LruCache(10, "mycache")
+        self.assertEqual(cache.max_size, 100)
+
 
 class LruCacheCallbacksTestCase(unittest.HomeserverTestCase):
     def test_get(self):
@@ -160,7 +166,7 @@ class LruCacheCallbacksTestCase(unittest.HomeserverTestCase):
         m2 = Mock()
         m3 = Mock()
         m4 = Mock()
-        cache = LruCache(4, 2, cache_type=TreeCache)
+        cache = LruCache(4, keylen=2, cache_type=TreeCache)
 
         cache.set(("a", "1"), "value", callbacks=[m1])
         cache.set(("a", "2"), "value", callbacks=[m2])
diff --git a/tests/utils.py b/tests/utils.py
index 867cf88977..1584eacb12 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -21,6 +21,7 @@ import time
 import uuid
 import warnings
 from inspect import getcallargs
+from typing import Type
 from urllib import parse as urlparse
 
 from mock import Mock, patch
@@ -38,6 +39,7 @@ from synapse.http.server import HttpServer
 from synapse.logging.context import current_context, set_current_context
 from synapse.server import HomeServer
 from synapse.storage import DataStore
+from synapse.storage.database import LoggingDatabaseConnection
 from synapse.storage.engines import PostgresEngine, create_engine
 from synapse.storage.prepare_database import prepare_database
 from synapse.util.ratelimitutils import FederationRateLimiter
@@ -88,6 +90,7 @@ def setupdb():
             host=POSTGRES_HOST,
             password=POSTGRES_PASSWORD,
         )
+        db_conn = LoggingDatabaseConnection(db_conn, db_engine, "tests")
         prepare_database(db_conn, db_engine, None)
         db_conn.close()
 
@@ -192,11 +195,10 @@ class TestHomeServer(HomeServer):
 def setup_test_homeserver(
     cleanup_func,
     name="test",
-    datastore=None,
     config=None,
     reactor=None,
-    homeserverToUse=TestHomeServer,
-    **kargs
+    homeserver_to_use: Type[HomeServer] = TestHomeServer,
+    **kwargs
 ):
     """
     Setup a homeserver suitable for running tests against.  Keyword arguments
@@ -219,8 +221,8 @@ def setup_test_homeserver(
 
     config.ldap_enabled = False
 
-    if "clock" not in kargs:
-        kargs["clock"] = MockClock()
+    if "clock" not in kwargs:
+        kwargs["clock"] = MockClock()
 
     if USE_POSTGRES_FOR_TESTS:
         test_db = "synapse_test_%s" % uuid.uuid4().hex
@@ -249,7 +251,7 @@ def setup_test_homeserver(
 
     # Create the database before we actually try and connect to it, based off
     # the template database we generate in setupdb()
-    if datastore is None and isinstance(db_engine, PostgresEngine):
+    if isinstance(db_engine, PostgresEngine):
         db_conn = db_engine.module.connect(
             database=POSTGRES_BASE_DB,
             user=POSTGRES_USER,
@@ -265,79 +267,68 @@ def setup_test_homeserver(
         cur.close()
         db_conn.close()
 
-    if datastore is None:
-        hs = homeserverToUse(
-            name,
-            config=config,
-            version_string="Synapse/tests",
-            tls_server_context_factory=Mock(),
-            tls_client_options_factory=Mock(),
-            reactor=reactor,
-            **kargs
-        )
+    hs = homeserver_to_use(
+        name, config=config, version_string="Synapse/tests", reactor=reactor,
+    )
 
-        hs.setup()
-        if homeserverToUse.__name__ == "TestHomeServer":
-            hs.setup_master()
+    # Install @cache_in_self attributes
+    for key, val in kwargs.items():
+        setattr(hs, "_" + key, val)
 
-        if isinstance(db_engine, PostgresEngine):
-            database = hs.get_datastores().databases[0]
+    # Mock TLS
+    hs.tls_server_context_factory = Mock()
+    hs.tls_client_options_factory = Mock()
 
-            # We need to do cleanup on PostgreSQL
-            def cleanup():
-                import psycopg2
+    hs.setup()
+    if homeserver_to_use == TestHomeServer:
+        hs.setup_background_tasks()
 
-                # Close all the db pools
-                database._db_pool.close()
+    if isinstance(db_engine, PostgresEngine):
+        database = hs.get_datastores().databases[0]
 
-                dropped = False
+        # We need to do cleanup on PostgreSQL
+        def cleanup():
+            import psycopg2
 
-                # Drop the test database
-                db_conn = db_engine.module.connect(
-                    database=POSTGRES_BASE_DB,
-                    user=POSTGRES_USER,
-                    host=POSTGRES_HOST,
-                    password=POSTGRES_PASSWORD,
-                )
-                db_conn.autocommit = True
-                cur = db_conn.cursor()
+            # Close all the db pools
+            database._db_pool.close()
 
-                # Try a few times to drop the DB. Some things may hold on to the
-                # database for a few more seconds due to flakiness, preventing
-                # us from dropping it when the test is over. If we can't drop
-                # it, warn and move on.
-                for x in range(5):
-                    try:
-                        cur.execute("DROP DATABASE IF EXISTS %s;" % (test_db,))
-                        db_conn.commit()
-                        dropped = True
-                    except psycopg2.OperationalError as e:
-                        warnings.warn(
-                            "Couldn't drop old db: " + str(e), category=UserWarning
-                        )
-                        time.sleep(0.5)
+            dropped = False
 
-                cur.close()
-                db_conn.close()
+            # Drop the test database
+            db_conn = db_engine.module.connect(
+                database=POSTGRES_BASE_DB,
+                user=POSTGRES_USER,
+                host=POSTGRES_HOST,
+                password=POSTGRES_PASSWORD,
+            )
+            db_conn.autocommit = True
+            cur = db_conn.cursor()
 
-                if not dropped:
-                    warnings.warn("Failed to drop old DB.", category=UserWarning)
+            # Try a few times to drop the DB. Some things may hold on to the
+            # database for a few more seconds due to flakiness, preventing
+            # us from dropping it when the test is over. If we can't drop
+            # it, warn and move on.
+            for x in range(5):
+                try:
+                    cur.execute("DROP DATABASE IF EXISTS %s;" % (test_db,))
+                    db_conn.commit()
+                    dropped = True
+                except psycopg2.OperationalError as e:
+                    warnings.warn(
+                        "Couldn't drop old db: " + str(e), category=UserWarning
+                    )
+                    time.sleep(0.5)
 
-            if not LEAVE_DB:
-                # Register the cleanup hook
-                cleanup_func(cleanup)
+            cur.close()
+            db_conn.close()
 
-    else:
-        hs = homeserverToUse(
-            name,
-            datastore=datastore,
-            config=config,
-            version_string="Synapse/tests",
-            tls_server_context_factory=Mock(),
-            tls_client_options_factory=Mock(),
-            reactor=reactor,
-            **kargs
-        )
+            if not dropped:
+                warnings.warn("Failed to drop old DB.", category=UserWarning)
+
+        if not LEAVE_DB:
+            # Register the cleanup hook
+            cleanup_func(cleanup)
 
     # bcrypt is far too slow to be doing in unit tests
     # Need to let the HS build an auth handler and then mess with it
@@ -353,7 +344,7 @@ def setup_test_homeserver(
 
     hs.get_auth_handler().validate_hash = validate_hash
 
-    fed = kargs.get("resource_for_federation", None)
+    fed = kwargs.get("resource_for_federation", None)
     if fed:
         register_federation_servlets(hs, fed)
 
diff --git a/tox.ini b/tox.ini
index 300417287a..69d23d5613 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = packaging, py35, py36, py37, py38, check_codestyle, check_isort
+envlist = packaging, py35, py36, py37, py38, py39, check_codestyle, check_isort
 
 [base]
 extras = test
@@ -24,11 +24,6 @@ deps =
     pip>=10
 
 setenv =
-    # we have a pyproject.toml, but don't want pip to use it for building.
-    # (otherwise we get an error about 'editable mode is not supported for
-    # pyproject.toml-style projects').
-    PIP_USE_PEP517 = false
-
     PYTHONDONTWRITEBYTECODE = no_byte_code
     COVERAGE_PROCESS_START = {toxinidir}/.coveragerc
 
@@ -111,7 +106,7 @@ commands =
 [testenv:packaging]
 skip_install=True
 deps =
-    check-manifest==0.41
+    check-manifest
 commands =
     check-manifest
 
@@ -131,7 +126,6 @@ skip_install = True
 deps = towncrier>=18.6.0rc1
 commands =
    python -m towncrier.check --compare-with=origin/dinsic
-basepython = python3.6
 
 [testenv:check-sampleconfig]
 commands = {toxinidir}/scripts-dev/generate_sample_config --check
@@ -161,7 +155,7 @@ commands=
 [testenv:mypy]
 deps =
     {[base]deps}
-extras = all, mypy
+extras = all,mypy
 commands = mypy
 
 # To find all folders that pass mypy you run: