Add rudimentary API for promoting/demoting other people in a group

For https://github.com/matrix-org/synapse/issues/2855 (initial)
Add a link to the matrix-synapse-rest-password-provider. (#8111 )
2020-08-18 15:21:30 -06:00 · 2020-08-18 09:54:35 -04:00 · 2020-08-18 09:53:13 -04:00 · 2020-08-18 14:14:27 +01:00 · 2020-08-18 09:09:11 -04:00 · 2020-08-18 08:49:59 -04:00
533 changed files with 7171 additions and 5862 deletions
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -4,18 +4,16 @@ jobs:
    machine: true
    steps:
      - checkout
-      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:${CIRCLE_TAG} -t matrixdotorg/synapse:${CIRCLE_TAG}-py3 .
+      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:${CIRCLE_TAG} .
      - run: docker login --username $DOCKER_HUB_USERNAME --password $DOCKER_HUB_PASSWORD
      - run: docker push matrixdotorg/synapse:${CIRCLE_TAG}
-      - run: docker push matrixdotorg/synapse:${CIRCLE_TAG}-py3
  dockerhubuploadlatest:
    machine: true
    steps:
      - checkout
-      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:latest -t matrixdotorg/synapse:latest-py3 .
+      - run: docker build -f docker/Dockerfile --label gitsha1=${CIRCLE_SHA1} -t matrixdotorg/synapse:latest .
      - run: docker login --username $DOCKER_HUB_USERNAME --password $DOCKER_HUB_PASSWORD
      - run: docker push matrixdotorg/synapse:latest
-      - run: docker push matrixdotorg/synapse:latest-py3

 workflows:
  version: 2
--- a/.github/ISSUE_TEMPLATE/BUG_REPORT.md
+++ b/.github/ISSUE_TEMPLATE/BUG_REPORT.md
@@ -4,12 +4,12 @@ about: Create a report to help us improve

 ---

+<!--
+
 **THIS IS NOT A SUPPORT CHANNEL!**
 **IF YOU HAVE SUPPORT QUESTIONS ABOUT RUNNING OR CONFIGURING YOUR OWN HOME SERVER**,
 please ask in **#synapse:matrix.org** (using a matrix.org account if necessary)

-<!--
-
 If you want to report a security issue, please see https://matrix.org/security-disclosure-policy/

 This is a bug report template. By following the instructions below and
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,91 @@
+For the next release
+====================
+
+Removal warning
+---------------
+
+Some older clients used a
+[disallowed character](https://matrix.org/docs/spec/client_server/r0.6.1#post-matrix-client-r0-register-email-requesttoken)
+(`:`) in the `client_secret` parameter of various endpoints. The incorrect
+behaviour was allowed for backwards compatibility, but is now being removed
+from Synapse as most users have updated their client. Further context can be
+found at [\#6766](https://github.com/matrix-org/synapse/issues/6766).
+
+
+Synapse 1.19.0 (2020-08-17)
+===========================
+
+No significant changes since 1.19.0rc1.
+
+Removal warning
+---------------
+
+As outlined in the [previous release](https://github.com/matrix-org/synapse/releases/tag/v1.18.0), we are no longer publishing Docker images with the `-py3` tag suffix. On top of that, we have also removed the `latest-py3` tag. Please see [the announcement in the upgrade notes for 1.18.0](https://github.com/matrix-org/synapse/blob/develop/UPGRADE.rst#upgrading-to-v1180).
+
+
+Synapse 1.19.0rc1 (2020-08-13)
+==============================
+
+Features
+--------
+
+- Add option to allow server admins to join rooms which fail complexity checks. Contributed by @lugino-emeritus. ([\#7902](https://github.com/matrix-org/synapse/issues/7902))
+- Add an option to purge room or not with delete room admin endpoint (`POST /_synapse/admin/v1/rooms/<room_id>/delete`). Contributed by @dklimpel. ([\#7964](https://github.com/matrix-org/synapse/issues/7964))
+- Add rate limiting to users joining rooms. ([\#8008](https://github.com/matrix-org/synapse/issues/8008))
+- Add a `/health` endpoint to every configured HTTP listener that can be used as a health check endpoint by load balancers. ([\#8048](https://github.com/matrix-org/synapse/issues/8048))
+- Allow login to be blocked based on the values of SAML attributes. ([\#8052](https://github.com/matrix-org/synapse/issues/8052))
+- Allow guest access to the `GET /_matrix/client/r0/rooms/{room_id}/members` endpoint, according to MSC2689. Contributed by Awesome Technologies Innovationslabor GmbH. ([\#7314](https://github.com/matrix-org/synapse/issues/7314))
+
+
+Bugfixes
+--------
+
+- Fix a bug introduced in Synapse v1.7.2 which caused inaccurate membership counts in the room directory. ([\#7977](https://github.com/matrix-org/synapse/issues/7977))
+- Fix a long standing bug: 'Duplicate key value violates unique constraint "event_relations_id"' when message retention is configured. ([\#7978](https://github.com/matrix-org/synapse/issues/7978))
+- Fix "no create event in auth events" when trying to reject invitation after inviter leaves. Bug introduced in Synapse v1.10.0. ([\#7980](https://github.com/matrix-org/synapse/issues/7980))
+- Fix various comments and minor discrepencies in server notices code. ([\#7996](https://github.com/matrix-org/synapse/issues/7996))
+- Fix a long standing bug where HTTP HEAD requests resulted in a 400 error. ([\#7999](https://github.com/matrix-org/synapse/issues/7999))
+- Fix a long-standing bug which caused two copies of some log lines to be written when synctl was used along with a MemoryHandler logger. ([\#8011](https://github.com/matrix-org/synapse/issues/8011), [\#8012](https://github.com/matrix-org/synapse/issues/8012))
+
+
+Updates to the Docker image
+---------------------------
+
+- We no longer publish Docker images with the `-py3` tag suffix, as [announced in the upgrade notes](https://github.com/matrix-org/synapse/blob/develop/UPGRADE.rst#upgrading-to-v1180). ([\#8056](https://github.com/matrix-org/synapse/issues/8056))
+
+
+Improved Documentation
+----------------------
+
+- Document how to set up a client .well-known file and fix several pieces of outdated documentation. ([\#7899](https://github.com/matrix-org/synapse/issues/7899))
+- Improve workers docs. ([\#7990](https://github.com/matrix-org/synapse/issues/7990), [\#8000](https://github.com/matrix-org/synapse/issues/8000))
+- Fix typo in `docs/workers.md`. ([\#7992](https://github.com/matrix-org/synapse/issues/7992))
+- Add documentation for how to undo a room shutdown. ([\#7998](https://github.com/matrix-org/synapse/issues/7998), [\#8010](https://github.com/matrix-org/synapse/issues/8010))
+
+
+Internal Changes
+----------------
+
+- Reduce the amount of whitespace in JSON stored and sent in responses. Contributed by David Vo. ([\#7372](https://github.com/matrix-org/synapse/issues/7372))
+- Switch to the JSON implementation from the standard library and bump the minimum version of the canonicaljson library to 1.2.0. ([\#7936](https://github.com/matrix-org/synapse/issues/7936), [\#7979](https://github.com/matrix-org/synapse/issues/7979))
+- Convert various parts of the codebase to async/await. ([\#7947](https://github.com/matrix-org/synapse/issues/7947), [\#7948](https://github.com/matrix-org/synapse/issues/7948), [\#7949](https://github.com/matrix-org/synapse/issues/7949), [\#7951](https://github.com/matrix-org/synapse/issues/7951), [\#7963](https://github.com/matrix-org/synapse/issues/7963), [\#7973](https://github.com/matrix-org/synapse/issues/7973), [\#7975](https://github.com/matrix-org/synapse/issues/7975), [\#7976](https://github.com/matrix-org/synapse/issues/7976), [\#7981](https://github.com/matrix-org/synapse/issues/7981), [\#7987](https://github.com/matrix-org/synapse/issues/7987), [\#7989](https://github.com/matrix-org/synapse/issues/7989), [\#8003](https://github.com/matrix-org/synapse/issues/8003), [\#8014](https://github.com/matrix-org/synapse/issues/8014), [\#8016](https://github.com/matrix-org/synapse/issues/8016), [\#8027](https://github.com/matrix-org/synapse/issues/8027), [\#8031](https://github.com/matrix-org/synapse/issues/8031), [\#8032](https://github.com/matrix-org/synapse/issues/8032), [\#8035](https://github.com/matrix-org/synapse/issues/8035), [\#8042](https://github.com/matrix-org/synapse/issues/8042), [\#8044](https://github.com/matrix-org/synapse/issues/8044), [\#8045](https://github.com/matrix-org/synapse/issues/8045), [\#8061](https://github.com/matrix-org/synapse/issues/8061), [\#8062](https://github.com/matrix-org/synapse/issues/8062), [\#8063](https://github.com/matrix-org/synapse/issues/8063), [\#8066](https://github.com/matrix-org/synapse/issues/8066), [\#8069](https://github.com/matrix-org/synapse/issues/8069), [\#8070](https://github.com/matrix-org/synapse/issues/8070))
+- Move some database-related log lines from the default logger to the database/transaction loggers. ([\#7952](https://github.com/matrix-org/synapse/issues/7952))
+- Add a script to detect source code files using non-unix line terminators. ([\#7965](https://github.com/matrix-org/synapse/issues/7965), [\#7970](https://github.com/matrix-org/synapse/issues/7970))
+- Log the SAML session ID during creation. ([\#7971](https://github.com/matrix-org/synapse/issues/7971))
+- Implement new experimental push rules for some users. ([\#7997](https://github.com/matrix-org/synapse/issues/7997))
+- Remove redundant and unreliable signature check for v1 Identity Service lookup responses. ([\#8001](https://github.com/matrix-org/synapse/issues/8001))
+- Improve the performance of the register endpoint. ([\#8009](https://github.com/matrix-org/synapse/issues/8009))
+- Reduce less useful output in the newsfragment CI step. Add a link to the changelog section of the contributing guide on error. ([\#8024](https://github.com/matrix-org/synapse/issues/8024))
+- Rename storage layer objects to be more sensible. ([\#8033](https://github.com/matrix-org/synapse/issues/8033))
+- Change the default log config to reduce disk I/O and storage for new servers. ([\#8040](https://github.com/matrix-org/synapse/issues/8040))
+- Add an assertion on `prev_events` in `create_new_client_event`. ([\#8041](https://github.com/matrix-org/synapse/issues/8041))
+- Add a comment to `ServerContextFactory` about the use of `SSLv23_METHOD`. ([\#8043](https://github.com/matrix-org/synapse/issues/8043))
+- Log `OPTIONS` requests at `DEBUG` rather than `INFO` level to reduce amount logged at `INFO`. ([\#8049](https://github.com/matrix-org/synapse/issues/8049))
+- Reduce amount of outbound request logging at `INFO` level. ([\#8050](https://github.com/matrix-org/synapse/issues/8050))
+- It is no longer necessary to explicitly define `filters` in the logging configuration. (Continuing to do so is redundant but harmless.) ([\#8051](https://github.com/matrix-org/synapse/issues/8051))
+- Add and improve type hints. ([\#8058](https://github.com/matrix-org/synapse/issues/8058), [\#8064](https://github.com/matrix-org/synapse/issues/8064), [\#8060](https://github.com/matrix-org/synapse/issues/8060), [\#8067](https://github.com/matrix-org/synapse/issues/8067))
+
+
 Synapse 1.18.0 (2020-07-30)
 ===========================

--- a/INSTALL.md
+++ b/INSTALL.md
@@ -1,10 +1,12 @@
 - [Choosing your server name](#choosing-your-server-name)
+- [Picking a database engine](#picking-a-database-engine)
 - [Installing Synapse](#installing-synapse)
  - [Installing from source](#installing-from-source)
    - [Platform-Specific Instructions](#platform-specific-instructions)
  - [Prebuilt packages](#prebuilt-packages)
 - [Setting up Synapse](#setting-up-synapse)
  - [TLS certificates](#tls-certificates)
+  - [Client Well-Known URI](#client-well-known-uri)
  - [Email](#email)
  - [Registering a user](#registering-a-user)
  - [Setting up a TURN server](#setting-up-a-turn-server)
@@ -27,6 +29,25 @@ that your email address is probably `user@example.com` rather than
 `user@email.example.com`) - but doing so may require more advanced setup: see
 [Setting up Federation](docs/federate.md).

+# Picking a database engine
+
+Synapse offers two database engines:
+ * [PostgreSQL](https://www.postgresql.org)
+ * [SQLite](https://sqlite.org/)
+
+Almost all installations should opt to use PostgreSQL. Advantages include:
+
+* significant performance improvements due to the superior threading and
+  caching model, smarter query optimiser
+* allowing the DB to be run on separate hardware
+
+For information on how to install and use PostgreSQL, please see
+[docs/postgres.md](docs/postgres.md)
+
+By default Synapse uses SQLite and in doing so trades performance for convenience.
+SQLite is only recommended in Synapse for testing purposes or for servers with
+light workloads.
+
 # Installing Synapse

 ## Installing from source
@@ -234,9 +255,9 @@ for a number of platforms.

 There is an offical synapse image available at
 https://hub.docker.com/r/matrixdotorg/synapse which can be used with
-the docker-compose file available at [contrib/docker](contrib/docker). Further information on
-this including configuration options is available in the README on
-hub.docker.com.
+the docker-compose file available at [contrib/docker](contrib/docker). Further
+information on this including configuration options is available in the README
+on hub.docker.com.

 Alternatively, Andreas Peters (previously Silvio Fricke) has contributed a
 Dockerfile to automate a synapse server in a single Docker image, at
@@ -244,7 +265,8 @@ https://hub.docker.com/r/avhost/docker-matrix/tags/

 Slavi Pantaleev has created an Ansible playbook,
 which installs the offical Docker image of Matrix Synapse
-along with many other Matrix-related services (Postgres database, riot-web, coturn, mxisd, SSL support, etc.).
+along with many other Matrix-related services (Postgres database, Element, coturn,
+ma1sd, SSL support, etc.).
 For more details, see
 https://github.com/spantaleev/matrix-docker-ansible-deploy

@@ -277,22 +299,27 @@ The fingerprint of the repository signing key (as shown by `gpg
 /usr/share/keyrings/matrix-org-archive-keyring.gpg`) is
 `AAF9AE843A7584B5A3E4CD2BCF45A512DE2DA058`.

-#### Downstream Debian/Ubuntu packages
+#### Downstream Debian packages

-For `buster` and `sid`, Synapse is available in the Debian repositories and
-it should be possible to install it with simply:
+We do not recommend using the packages from the default Debian `buster`
+repository at this time, as they are old and suffer from known security
+vulnerabilities. You can install the latest version of Synapse from
+[our repository](#matrixorg-packages) or from `buster-backports`. Please
+see the [Debian documentation](https://backports.debian.org/Instructions/)
+for information on how to use backports.
+
+If you are using Debian `sid` or testing, Synapse is available in the default
+repositories and it should be possible to install it simply with:

 ```
 sudo apt install matrix-synapse
 ```

-There is also a version of `matrix-synapse` in `stretch-backports`. Please see
-the [Debian documentation on
-backports](https://backports.debian.org/Instructions/) for information on how
-to use them.
+#### Downstream Ubuntu packages

-We do not recommend using the packages in downstream Ubuntu at this time, as
-they are old and suffer from known security vulnerabilities.
+We do not recommend using the packages in the default Ubuntu repository
+at this time, as they are old and suffer from known security vulnerabilities.
+The latest version of Synapse can be installed from [our repository](#matrixorg-packages).

 ### Fedora

@@ -419,6 +446,60 @@ so, you will need to edit `homeserver.yaml`, as follows:
 For a more detailed guide to configuring your server for federation, see
 [federate.md](docs/federate.md).

+## Client Well-Known URI
+
+Setting up the client Well-Known URI is optional but if you set it up, it will
+allow users to enter their full username (e.g. `@user:<server_name>`) into clients
+which support well-known lookup to automatically configure the homeserver and
+identity server URLs. This is useful so that users don't have to memorize or think
+about the actual homeserver URL you are using.
+
+The URL `https://<server_name>/.well-known/matrix/client` should return JSON in
+the following format.
+
+```
+{
+  "m.homeserver": {
+    "base_url": "https://<matrix.example.com>"
+  }
+}
+```
+
+It can optionally contain identity server information as well.
+
+```
+{
+  "m.homeserver": {
+    "base_url": "https://<matrix.example.com>"
+  },
+  "m.identity_server": {
+    "base_url": "https://<identity.example.com>"
+  }
+}
+```
+
+To work in browser based clients, the file must be served with the appropriate
+Cross-Origin Resource Sharing (CORS) headers. A recommended value would be
+`Access-Control-Allow-Origin: *` which would allow all browser based clients to
+view it.
+
+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;
+    add_header Access-Control-Allow-Origin *;
+}
+```
+
+You should also ensure the `public_baseurl` option in `homeserver.yaml` is set
+correctly. `public_baseurl` should be set to the URL that clients will use to
+connect to your server. This is the same URL you put for the `m.homeserver`
+`base_url` above.
+
+```
+public_baseurl: "https://<matrix.example.com>"
+```

 ## Email

@@ -437,7 +518,7 @@ email will be disabled.

 ## Registering a user

-The easiest way to create a new user is to do so from a client like [Riot](https://riot.im).
+The easiest way to create a new user is to do so from a client like [Element](https://element.io/).

 Alternatively you can do so from the command line if you have installed via pip.

--- a/README.rst
+++ b/README.rst
@@ -45,7 +45,7 @@ which handle:
 - Eventually-consistent cryptographically secure synchronisation of room
  state across a global open network of federated servers and services
 - Sending and receiving extensible messages in a room with (optional)
-  end-to-end encryption[1]
+  end-to-end encryption
 - Inviting, joining, leaving, kicking, banning room members
 - Managing user accounts (registration, login, logout)
 - Using 3rd Party IDs (3PIDs) such as email addresses, phone numbers,
@@ -82,9 +82,6 @@ at the `Matrix spec <https://matrix.org/docs/spec>`_, and experiment with the

 Thanks for using Matrix!

-[1] End-to-end encryption is currently in beta: `blog post <https://matrix.org/blog/2016/11/21/matrixs-olm-end-to-end-encryption-security-assessment-released-and-implemented-cross-platform-on-riot-at-last>`_.
-
-
 Support
 =======

@@ -115,12 +112,11 @@ Unless you are running a test instance of Synapse on your local machine, in
 general, you will need to enable TLS support before you can successfully
 connect from a client: see `<INSTALL.md#tls-certificates>`_.

-An easy way to get started is to login or register via Riot at
-https://riot.im/app/#/login or https://riot.im/app/#/register respectively.
+An easy way to get started is to login or register via Element at
+https://app.element.io/#/login or https://app.element.io/#/register respectively.
 You will need to change the server you are logging into from ``matrix.org``
 and instead specify a Homeserver URL of ``https://<server_name>:8448``
 (or just ``https://<server_name>`` if you are using a reverse proxy).
-(Leave the identity server as the default - see `Identity servers`_.)
 If you prefer to use another client, refer to our
 `client breakdown <https://matrix.org/docs/projects/clients-matrix>`_.

@@ -137,7 +133,7 @@ it, specify ``enable_registration: true`` in ``homeserver.yaml``. (It is then
 recommended to also set up CAPTCHA - see `<docs/CAPTCHA_SETUP.md>`_.)

 Once ``enable_registration`` is set to ``true``, it is possible to register a
-user via `riot.im <https://riot.im/app/#/register>`_ or other Matrix clients.
+user via a Matrix client.

 Your new user name will be formed partly from the ``server_name``, and partly
 from a localpart you specify when you create the account. Your name will take
@@ -183,30 +179,6 @@ versions of synapse.

 .. _UPGRADE.rst: UPGRADE.rst

-
-Using PostgreSQL
-================
-
-Synapse offers two database engines:
- * `PostgreSQL <https://www.postgresql.org>`_
- * `SQLite <https://sqlite.org/>`_
-
-Almost all installations should opt to use PostgreSQL. Advantages include:
-
-* significant performance improvements due to the superior threading and
-  caching model, smarter query optimiser
-* allowing the DB to be run on separate hardware
-* allowing basic active/backup high-availability with a "hot spare" synapse
-  pointing at the same DB master, as well as enabling DB replication in
-  synapse itself.
-
-For information on how to install and use PostgreSQL, please see
-`docs/postgres.md <docs/postgres.md>`_.
-
-By default Synapse uses SQLite and in doing so trades performance for convenience.
-SQLite is only recommended in Synapse for testing purposes or for servers with
-light workloads.
-
 .. _reverse-proxy:

 Using a reverse proxy with Synapse
@@ -255,10 +227,9 @@ email address.
 Password reset
 ==============

-If a user has registered an email address to their account using an identity
-server, they can request a password-reset token via clients such as Riot.
-
-A manual password reset can be done via direct database access as follows.
+Users can reset their password through their client. Alternatively, a server admin
+can reset a users password using the `admin API <docs/admin_api/user_admin_api.rst#reset-password>`_
+or by directly editing the database as shown below.

 First calculate the hash of the new password::

--- a/changelog.d/7864.bugfix
+++ b/changelog.d/7864.bugfix
@@ -0,0 +1 @@
+Fix a memory leak by limiting the length of time that messages will be queued for a remote server that has been unreachable.
--- a/changelog.d/8013.feature
+++ b/changelog.d/8013.feature
@@ -0,0 +1 @@
+Iteratively encode JSON to avoid blocking the reactor.
--- a/changelog.d/8037.feature
+++ b/changelog.d/8037.feature
@@ -0,0 +1 @@
+Use the default template file when its equivalent is not found in a custom template directory.
--- a/changelog.d/8072.misc
+++ b/changelog.d/8072.misc
@@ -0,0 +1 @@
+Convert various parts of the codebase to async/await.
--- a/changelog.d/8074.misc
+++ b/changelog.d/8074.misc
@@ -0,0 +1 @@
+Convert various parts of the codebase to async/await.
--- a/changelog.d/8075.misc
+++ b/changelog.d/8075.misc
@@ -0,0 +1 @@
+Convert various parts of the codebase to async/await.
--- a/changelog.d/8076.misc
+++ b/changelog.d/8076.misc
@@ -0,0 +1 @@
+Convert various parts of the codebase to async/await.
--- a/changelog.d/8081.bugfix
+++ b/changelog.d/8081.bugfix
@@ -0,0 +1 @@
+Fix `Re-starting finished log context PUT-nnnn` warning when event persistence failed.
--- a/changelog.d/8085.misc
+++ b/changelog.d/8085.misc
@@ -0,0 +1 @@
+Remove some unused database functions.
--- a/changelog.d/8087.misc
+++ b/changelog.d/8087.misc
@@ -0,0 +1 @@
+Convert various parts of the codebase to async/await.
--- a/changelog.d/8090.misc
+++ b/changelog.d/8090.misc
@@ -0,0 +1 @@
+Add type hints to `synapse.handlers.room`.
--- a/changelog.d/8092.feature
+++ b/changelog.d/8092.feature
@@ -0,0 +1 @@
+Add support for shadow-banning users (ignoring any message send requests).
--- a/changelog.d/8093.misc
+++ b/changelog.d/8093.misc
@@ -0,0 +1 @@
+Return the previous stream token if a non-member event is a duplicate.
--- a/changelog.d/8100.misc
+++ b/changelog.d/8100.misc
@@ -0,0 +1 @@
+Convert various parts of the codebase to async/await.
--- a/changelog.d/8101.bugfix
+++ b/changelog.d/8101.bugfix
@@ -0,0 +1 @@
+Synapse now correctly enforces the valid characters in the `client_secret` parameter used in various endpoints.
--- a/changelog.d/8107.feature
+++ b/changelog.d/8107.feature
@@ -0,0 +1 @@
+Use the default template file when its equivalent is not found in a custom template directory.
--- a/changelog.d/8111.doc
+++ b/changelog.d/8111.doc
@@ -0,0 +1 @@
+Link to matrix-synapse-rest-password-provider in the password provider documentation.
--- a/changelog.d/8112.misc
+++ b/changelog.d/8112.misc
@@ -0,0 +1 @@
+Return the previous stream token if a non-member event is a duplicate.
--- a/contrib/cmdclient/console.py
+++ b/contrib/cmdclient/console.py
@@ -609,13 +609,15 @@ class SynapseCmd(cmd.Cmd):

    @defer.inlineCallbacks
    def _do_event_stream(self, timeout):
-        res = yield self.http_client.get_json(
-            self._url() + "/events",
-            {
-                "access_token": self._tok(),
-                "timeout": str(timeout),
-                "from": self.event_stream_token,
-            },
+        res = yield defer.ensureDeferred(
+            self.http_client.get_json(
+                self._url() + "/events",
+                {
+                    "access_token": self._tok(),
+                    "timeout": str(timeout),
+                    "from": self.event_stream_token,
+                },
+            )
        )
        print(json.dumps(res, indent=4))

--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,13 @@
+matrix-synapse-py3 (1.19.0) stable; urgency=medium
+
+  [ Synapse Packaging team ]
+  * New synapse release 1.19.0.
+
+  [ Aaron Raimist ]
+  * Fix outdated documentation for SYNAPSE_CACHE_FACTOR
+
+ -- Synapse Packaging team <packages@matrix.org>  Mon, 17 Aug 2020 14:06:42 +0100
+
 matrix-synapse-py3 (1.18.0) stable; urgency=medium

  * New synapse release 1.18.0.
--- a/debian/matrix-synapse.default
+++ b/debian/matrix-synapse.default
@@ -1,2 +1,2 @@
 # Specify environment variables used when running Synapse
-# SYNAPSE_CACHE_FACTOR=1 (default)
+# SYNAPSE_CACHE_FACTOR=0.5 (default)
--- a/debian/synctl.ronn
+++ b/debian/synctl.ronn
@@ -46,19 +46,20 @@ Configuration file may be generated as follows:
 ## ENVIRONMENT

  * `SYNAPSE_CACHE_FACTOR`:
-    Synapse's architecture is quite RAM hungry currently - a lot of
-    recent room data and metadata is deliberately cached in RAM in
-    order to speed up common requests.  This will be improved in
-    future, but for now the easiest way to either reduce the RAM usage
-    (at the risk of slowing things down) is to set the
-    SYNAPSE_CACHE_FACTOR environment variable. Roughly speaking, a
-    SYNAPSE_CACHE_FACTOR of 1.0 will max out at around 3-4GB of
-    resident memory - this is what we currently run the matrix.org
-    on. The default setting is currently 0.1, which is probably around
-    a ~700MB footprint. You can dial it down further to 0.02 if
-    desired, which targets roughly ~512MB. Conversely you can dial it
-    up if you need performance for lots of users and have a box with a
-    lot of RAM.
+    Synapse's architecture is quite RAM hungry currently - we deliberately
+    cache a lot of recent room data and metadata in RAM in order to speed up
+    common requests. We'll improve this in the future, but for now the easiest
+    way to either reduce the RAM usage (at the risk of slowing things down)
+    is to set the almost-undocumented ``SYNAPSE_CACHE_FACTOR`` environment
+    variable. The default is 0.5, which can be decreased to reduce RAM usage
+    in memory constrained enviroments, or increased if performance starts to
+    degrade.
+
+    However, degraded performance due to a low cache factor, common on
+    machines with slow disks, often leads to explosions in memory use due
+    backlogged requests. In this case, reducing the cache factor will make
+    things worse. Instead, try increasing it drastically. 2.0 is a good
+    starting value.

 ## COPYRIGHT

--- a/docker/conf/log.config
+++ b/docker/conf/log.config
@@ -4,16 +4,10 @@ formatters:
  precise:
   format: '%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s'

-filters:
-  context:
-    (): synapse.logging.context.LoggingContextFilter
-    request: ""
-
 handlers:
  console:
    class: logging.StreamHandler
    formatter: precise
-    filters: [context]

 loggers:
    synapse.storage.SQL:
--- a/docs/.sample_config_header.yaml
+++ b/docs/.sample_config_header.yaml
@@ -10,5 +10,16 @@
 # homeserver.yaml. Instead, if you are starting from scratch, please generate
 # a fresh config using Synapse by following the instructions in INSTALL.md.

+# Configuration options that take a time period can be set using a number
+# followed by a letter. Letters have the following meanings:
+# s = second
+# m = minute
+# h = hour
+# d = day
+# w = week
+# y = year
+# For example, setting redaction_retention_period: 5m would remove redacted
+# messages from the database after 5 minutes, rather than 5 months.
+
 ################################################################################

--- a/docs/admin_api/rooms.md
+++ b/docs/admin_api/rooms.md
@@ -369,7 +369,9 @@ to the new room will have power level `-10` by default, and thus be unable to sp
 If `block` is `True` it prevents new joins to the old room.

 This API will remove all trace of the old room from your database after removing
-all local users.
+all local users. If `purge` is `true` (the default), all traces of the old room will
+be removed from your database after removing all local users. If you do not want
+this to happen, set `purge` to `false`.
 Depending on the amount of history being purged a call to the API may take
 several minutes or longer.

@@ -388,7 +390,8 @@ with a body of:
    "new_room_user_id": "@someuser:example.com",
    "room_name": "Content Violation Notification",
    "message": "Bad Room has been shutdown due to content violations on this server. Please review our Terms of Service.",
-    "block": true
+    "block": true,
+    "purge": true
 }
 ```

@@ -430,8 +433,10 @@ The following JSON body parameters are available:
              `new_room_user_id` in the new room. Ideally this will clearly convey why the
               original room was shut down. Defaults to `Sharing illegal content on this server
               is not permitted and rooms in violation will be blocked.`
-* `block` - Optional. If set to `true`, this room will be added to a blocking list, preventing future attempts to
-  join the room. Defaults to `false`.
+* `block` - Optional. If set to `true`, this room will be added to a blocking list, preventing
+            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`.

 The JSON body must not be empty. The body must be at least `{}`.

--- a/docs/admin_api/shutdown_room.md
+++ b/docs/admin_api/shutdown_room.md
@@ -33,7 +33,7 @@ You will need to authenticate with an access token for an admin user.
 * `message` - Optional. A string containing the first message that will be sent as
              `new_room_user_id` in the new room. Ideally this will clearly convey why the
               original room was shut down.
-              
+
 If not specified, the default value of `room_name` is "Content Violation
 Notification". The default value of `message` is "Sharing illegal content on
 othis server is not permitted and rooms in violation will be blocked."
@@ -72,3 +72,30 @@ Response:
    "new_room_id": "!newroomid:example.com",
 },
 ```
+
+## Undoing room shutdowns
+
+*Note*: This guide may be outdated by the time you read it. By nature of room shutdowns being performed at the database level,
+the structure can and does change without notice.
+
+First, it's important to understand that a room shutdown is very destructive. Undoing a shutdown is not as simple as pretending it
+never happened - work has to be done to move forward instead of resetting the past. In fact, in some cases it might not be possible
+to recover at all:
+
+* If the room was invite-only, your users will need to be re-invited.
+* If the room no longer has any members at all, it'll be impossible to rejoin.
+* The first user to rejoin will have to do so via an alias on a different server.
+
+With all that being said, if you still want to try and recover the room:
+
+1. For safety reasons, shut down Synapse.
+2. In the database, run `DELETE FROM blocked_rooms WHERE room_id = '!example:example.org';`
+   * For caution: it's recommended to run this in a transaction: `BEGIN; DELETE ...;`, verify you got 1 result, then `COMMIT;`.
+   * The room ID is the same one supplied to the shutdown room API, not the Content Violation room.
+3. Restart Synapse.
+
+You will have to manually handle, if you so choose, the following:
+
+* Aliases that would have been redirected to the Content Violation room.
+* Users that would have been booted from the room (and will have been force-joined to the Content Violation room).
+* Removal of the Content Violation room if desired.
--- a/docs/metrics-howto.md
+++ b/docs/metrics-howto.md
@@ -27,7 +27,7 @@
    different thread to Synapse. This can make it more resilient to
    heavy load meaning metrics cannot be retrieved, and can be exposed
    to just internal networks easier. The served metrics are available
-    over HTTP only, and will be available at `/`.
+    over HTTP only, and will be available at `/_synapse/metrics`.

    Add a new listener to homeserver.yaml:

--- a/docs/password_auth_providers.md
+++ b/docs/password_auth_providers.md
@@ -14,6 +14,7 @@ password auth provider module implementations:

 * [matrix-synapse-ldap3](https://github.com/matrix-org/matrix-synapse-ldap3/)
 * [matrix-synapse-shared-secret-auth](https://github.com/devture/matrix-synapse-shared-secret-auth)
+* [matrix-synapse-rest-password-provider](https://github.com/ma1uta/matrix-synapse-rest-password-provider)

 ## Required methods

--- a/docs/postgres.md
+++ b/docs/postgres.md
@@ -188,6 +188,9 @@ to do step 2.

 It is safe to at any time kill the port script and restart it.

+Note that the database may take up significantly more (25% - 100% more)
+space on disk after porting to Postgres.
+
 ### Using the port script

 Firstly, shut down the currently running synapse server and copy its
--- a/docs/reverse_proxy.md
+++ b/docs/reverse_proxy.md
@@ -139,3 +139,10 @@ client IP addresses are recorded correctly.
 Having done so, you can then use `https://matrix.example.com` (instead
 of `https://matrix.example.com:8448`) as the "Custom server" when
 connecting to Synapse from a client.
+
+
+## Health check endpoint
+
+Synapse exposes a health check endpoint for use by reverse proxies.
+Each configured HTTP listener has a `/health` endpoint which always returns
+200 OK (and doesn't get logged).
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -10,6 +10,17 @@
 # homeserver.yaml. Instead, if you are starting from scratch, please generate
 # a fresh config using Synapse by following the instructions in INSTALL.md.

+# Configuration options that take a time period can be set using a number
+# followed by a letter. Letters have the following meanings:
+# s = second
+# m = minute
+# h = hour
+# d = day
+# w = week
+# y = year
+# For example, setting redaction_retention_period: 5m would remove redacted
+# messages from the database after 5 minutes, rather than 5 months.
+
 ################################################################################

 # Configuration file for Synapse.
@@ -314,6 +325,10 @@ limit_remote_rooms:
  #
  #complexity_error: "This room is too complex."

+  # allow server admins to join complex rooms. Default is false.
+  #
+  #admins_can_join: true
+
 # Whether to require a user to be in the room to add an alias to it.
 # Defaults to 'true'.
 #
@@ -731,6 +746,10 @@ log_config: "CONFDIR/SERVERNAME.log.config"
 #   - one for ratelimiting redactions by room admins. If this is not explicitly
 #     set then it uses the same ratelimiting as per rc_message. This is useful
 #     to allow room admins to deal with abuse quickly.
+#   - two for ratelimiting number of rooms a user can join, "local" for when
+#     users are joining rooms the server is already in (this is cheap) vs
+#     "remote" for when users are trying to join rooms not on the server (which
+#     can be more expensive)
 #
 # The defaults are as shown below.
 #
@@ -756,6 +775,14 @@ log_config: "CONFDIR/SERVERNAME.log.config"
 #rc_admin_redaction:
 #  per_second: 1
 #  burst_count: 50
+#
+#rc_joins:
+#  local:
+#    per_second: 0.1
+#    burst_count: 3
+#  remote:
+#    per_second: 0.01
+#    burst_count: 3


 # Ratelimiting settings for incoming federation
@@ -1145,24 +1172,6 @@ account_validity:
 #
 #default_identity_server: https://matrix.org

-# The list of identity servers trusted to verify third party
-# identifiers by this server.
-#
-# Also defines the ID server which will be called when an account is
-# deactivated (one will be picked arbitrarily).
-#
-# Note: This option is deprecated. Since v0.99.4, Synapse has tracked which identity
-# server a 3PID has been bound to. For 3PIDs bound before then, Synapse runs a
-# background migration script, informing itself that the identity server all of its
-# 3PIDs have been bound to is likely one of the below.
-#
-# As of Synapse v1.4.0, all other functionality of this option has been deprecated, and
-# it is now solely used for the purposes of the background migration script, and can be
-# removed once it has run.
-#trusted_third_party_id_servers:
-#  - matrix.org
-#  - vector.im
-
 # Handle threepid (email/phone etc) registration and password resets through a set of
 # *trusted* identity servers. Note that this allows the configured identity server to
 # reset passwords for accounts!
@@ -1568,6 +1577,17 @@ saml2_config:
  #
  #grandfathered_mxid_source_attribute: upn

+  # It is possible to configure Synapse to only allow logins if SAML attributes
+  # match particular values. The requirements can be listed under
+  # `attribute_requirements` as shown below. All of the listed attributes must
+  # match for the login to be permitted.
+  #
+  #attribute_requirements:
+  #  - attribute: userGroup
+  #    value: "staff"
+  #  - attribute: department
+  #    value: "sales"
+
  # Directory in which Synapse will try to find the template files below.
  # If not set, default templates from within the Synapse package will be used.
  #
@@ -1982,9 +2002,7 @@ email:
  # Directory in which Synapse will try to find the template files below.
  # If not set, default templates from within the Synapse package will be used.
  #
-  # DO NOT UNCOMMENT THIS SETTING unless you want to customise the templates.
-  # If you *do* uncomment it, you will need to make sure that all the templates
-  # below are in the directory.
+  # Do not uncomment this setting unless you want to customise the templates.
  #
  # Synapse will look for the following templates in this directory:
  #
--- a/docs/sample_log_config.yaml
+++ b/docs/sample_log_config.yaml
@@ -11,24 +11,33 @@ formatters:
    precise:
        format: '%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s'

-filters:
-    context:
-        (): synapse.logging.context.LoggingContextFilter
-        request: ""
-
 handlers:
    file:
-        class: logging.handlers.RotatingFileHandler
+        class: logging.handlers.TimedRotatingFileHandler
        formatter: precise
        filename: /var/log/matrix-synapse/homeserver.log
-        maxBytes: 104857600
-        backupCount: 10
-        filters: [context]
+        when: midnight
+        backupCount: 3  # Does not include the current log file.
        encoding: utf8
+
+    # Default to buffering writes to log file for efficiency. This means that
+    # will be a delay for INFO/DEBUG logs to get written, but WARNING/ERROR
+    # logs will still be flushed immediately.
+    buffer:
+        class: logging.handlers.MemoryHandler
+        target: file
+        # The capacity is the number of log lines that are buffered before
+        # being written to disk. Increasing this will lead to better
+        # performance, at the expensive of it taking longer for log lines to
+        # be written to disk.
+        capacity: 10
+        flushLevel: 30  # Flush for WARNING logs as well
+
+    # A handler that writes logs to stderr. Unused by default, but can be used
+    # instead of "buffer" and "file" in the logger handlers.
    console:
        class: logging.StreamHandler
        formatter: precise
-        filters: [context]

 loggers:
    synapse.storage.SQL:
@@ -36,8 +45,23 @@ loggers:
        # information such as access tokens.
        level: INFO

+    twisted:
+        # We send the twisted logging directly to the file handler,
+        # to work around https://github.com/matrix-org/synapse/issues/3471
+        # when using "buffer" logger. Use "console" to log to stderr instead.
+        handlers: [file]
+        propagate: false
+
 root:
    level: INFO
-    handlers: [file, console]
+
+    # Write logs to the `buffer` handler, which will buffer them together in memory,
+    # 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
+    # this case.)
+    #
+    handlers: [buffer]

 disable_existing_loggers: false
--- a/docs/systemd-with-workers/workers/federation_reader.yaml
+++ b/docs/systemd-with-workers/workers/federation_reader.yaml
@@ -1,7 +1,7 @@
 worker_app: synapse.app.federation_reader
+worker_name: federation_reader1

 worker_replication_host: 127.0.0.1
-worker_replication_port: 9092
 worker_replication_http_port: 9093

 worker_listeners:
--- a/docs/user_directory.md
+++ b/docs/user_directory.md
@@ -7,6 +7,6 @@ who are present in a publicly viewable room present on the server.

 The directory info is stored in various tables, which can (typically after
 DB corruption) get stale or out of sync.  If this happens, for now the
-solution to fix it is to execute the SQL [here](../synapse/storage/data_stores/main/schema/delta/53/user_dir_populate.sql)
+solution to fix it is to execute the SQL [here](../synapse/storage/databases/main/schema/delta/53/user_dir_populate.sql)
 and then restart synapse. This should then start a background task to
 flush the current tables and regenerate the directory.
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -1,10 +1,10 @@
 # Scaling synapse via workers

-For small instances it recommended to run Synapse in monolith mode (the
-default). For larger instances where performance is a concern it can be helpful
-to split out functionality into multiple separate python processes. These
-processes are called 'workers', and are (eventually) intended to scale
-horizontally independently.
+For small instances it recommended to run Synapse in the default monolith mode.
+For larger instances where performance is a concern it can be helpful to split
+out functionality into multiple separate python processes. These processes are
+called 'workers', and are (eventually) intended to scale horizontally
+independently.

 Synapse's worker support is under active development and subject to change as
 we attempt to rapidly scale ever larger Synapse instances. However we are
@@ -23,29 +23,30 @@ The processes communicate with each other via a Synapse-specific protocol called
 feeds streams of newly written data between processes so they can be kept in
 sync with the database state.

-Additionally, processes may make HTTP requests to each other. Typically this is
-used for operations which need to wait for a reply - such as sending an event.
+When configured to do so, Synapse uses a
+[Redis pub/sub channel](https://redis.io/topics/pubsub) to send the replication
+stream between all configured Synapse processes. Additionally, processes may
+make HTTP requests to each other, primarily for operations which need to wait
+for a reply ─ such as sending an event.

-As of Synapse v1.13.0, it is possible to configure Synapse to send replication
-via a [Redis pub/sub channel](https://redis.io/topics/pubsub), and is now the
-recommended way of configuring replication. This is an alternative to the old
-direct TCP connections to the main process: rather than all the workers
-connecting to the main process, all the workers and the main process connect to
-Redis, which relays replication commands between processes. This can give a
-significant cpu saving on the main process and will be a prerequisite for
-upcoming performance improvements.
+Redis support was added in v1.13.0 with it becoming the recommended method in
+v1.18.0. It replaced the old direct TCP connections (which is deprecated as of
+v1.18.0) to the main process. With Redis, rather than all the workers connecting
+to the main process, all the workers and the main process connect to Redis,
+which relays replication commands between processes. This can give a significant
+cpu saving on the main process and will be a prerequisite for upcoming
+performance improvements.

-(See the [Architectural diagram](#architectural-diagram) section at the end for
-a visualisation of what this looks like)
+See the [Architectural diagram](#architectural-diagram) section at the end for
+a visualisation of what this looks like.


 ## Setting up workers

 A Redis server is required to manage the communication between the processes.
-(The older direct TCP connections are now deprecated.) The Redis server
-should be installed following the normal procedure for your distribution (e.g.
-`apt install redis-server` on Debian). It is safe to use an existing Redis
-deployment if you have one.
+The Redis server should be installed following the normal procedure for your
+distribution (e.g. `apt install redis-server` on Debian). It is safe to use an
+existing Redis deployment if you have one.

 Once installed, check that Redis is running and accessible from the host running
 Synapse, for example by executing `echo PING | nc -q1 localhost 6379` and seeing
@@ -65,18 +66,31 @@ https://hub.docker.com/r/matrixdotorg/synapse/.

 To make effective use of the workers, you will need to configure an HTTP
 reverse-proxy such as nginx or haproxy, which will direct incoming requests to
-the correct worker, or to the main synapse instance. See [reverse_proxy.md](reverse_proxy.md)
-for information on setting up a reverse proxy.
+the correct worker, or to the main synapse instance. See
+[reverse_proxy.md](reverse_proxy.md) for information on setting up a reverse
+proxy.

-To enable workers you should create a configuration file for each worker
-process. Each worker configuration file inherits the configuration of the shared
-homeserver configuration file.  You can then override configuration specific to
-that worker, e.g. the HTTP listener that it provides (if any); logging
-configuration; etc.  You should minimise the number of overrides though to
-maintain a usable config.
+When using workers, each worker process has its own configuration file which
+contains settings specific to that worker, such as the HTTP listener that it
+provides (if any), logging configuration, etc.
+
+Normally, the worker processes are configured to read from a shared
+configuration file as well as the worker-specific configuration files. This
+makes it easier to keep common configuration settings synchronised across all
+the processes.
+
+The main process is somewhat special in this respect: it does not normally
+need its own configuration file and can take all of its configuration from the
+shared configuration file.
+
+
+### Shared configuration
+
+Normally, only a couple of changes are needed to make an existing configuration
+file suitable for use with workers. First, you need to enable an "HTTP replication
+listener" for the main process; and secondly, you need to enable redis-based
+replication. For example:

-Next you need to add both a HTTP replication listener and redis config to the
-shared Synapse configuration file (`homeserver.yaml`). For example:

 ```yaml
 # extend the existing `listeners` section. This defines the ports that the
@@ -98,6 +112,9 @@ See the sample config for the full documentation of each option.
 Under **no circumstances** should the replication listener be exposed to the
 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
 (`worker_name`). The currently available worker applications are listed below.
@@ -136,6 +153,9 @@ plain HTTP endpoint on port 8083 separately serving various endpoints, e.g.
 Obviously you should configure your reverse-proxy to route the relevant
 endpoints to the worker (`localhost:8083` in the above example).

+
+### Running Synapse with workers
+
 Finally, you need to start your worker processes. This can be done with either
 `synctl` or your distribution's preferred service manager such as `systemd`. We
 recommend the use of `systemd` where available: for information on setting up
@@ -278,7 +298,7 @@ instance_map:
        host: localhost
        port: 8034

-streams_writers:
+stream_writers:
    events: event_persister1
 ```

@@ -398,6 +418,23 @@ all these to be folded into the `generic_worker` app and to use config to define
 which processes handle the various proccessing such as push notifications.


+## Migration from old config
+
+There are two main independent changes that have been made: introducing Redis
+support and merging apps into `synapse.app.generic_worker`. Both these changes
+are backwards compatible and so no changes to the config are required, however
+server admins are encouraged to plan to migrate to Redis as the old style direct
+TCP replication config is deprecated.
+
+To migrate to Redis add the `redis` config as above, and optionally remove the
+TCP `replication` listener from master and `worker_replication_port` from worker
+config.
+
+To migrate apps to use `synapse.app.generic_worker` simply update the
+`worker_app` option in the worker configs, and where worker are started (e.g.
+in systemd service files, but not required for synctl).
+
+
 ## Architectural diagram

 The following shows an example setup using Redis and a reverse proxy:
--- a/mypy.ini
+++ b/mypy.ini
@@ -81,3 +81,6 @@ ignore_missing_imports = True

 [mypy-rust_python_jaeger_reporter.*]
 ignore_missing_imports = True
+
+[mypy-nacl.*]
+ignore_missing_imports = True
--- a/scripts-dev/check-newsfragment
+++ b/scripts-dev/check-newsfragment
@@ -3,6 +3,8 @@
 # A script which checks that an appropriate news file has been added on this
 # branch.

+echo -e "+++ \033[32mChecking newsfragment\033[m"
+
 set -e

 # make sure that origin/develop is up to date
@@ -16,6 +18,8 @@ pr="$BUILDKITE_PULL_REQUEST"
 if ! git diff --quiet FETCH_HEAD... -- debian; then
    if git diff --quiet FETCH_HEAD... -- debian/changelog; then
        echo "Updates to debian directory, but no update to the changelog." >&2
+        echo "!! Please see the contributing guide for help writing your changelog entry:" >&2
+        echo "https://github.com/matrix-org/synapse/blob/develop/CONTRIBUTING.md#debian-changelog" >&2
        exit 1
    fi
 fi
@@ -26,7 +30,12 @@ if ! git diff --name-only FETCH_HEAD... | grep -qv '^debian/'; then
    exit 0
 fi

-tox -qe check-newsfragment
+# Print a link to the contributing guide if the user makes a mistake
+CONTRIBUTING_GUIDE_TEXT="!! Please see the contributing guide for help writing your changelog entry:
+https://github.com/matrix-org/synapse/blob/develop/CONTRIBUTING.md#changelog"
+
+# If check-newsfragment returns a non-zero exit code, print the contributing guide and exit
+tox -qe check-newsfragment || (echo -e "$CONTRIBUTING_GUIDE_TEXT" >&2 && exit 1)

 echo
 echo "--------------------------"
@@ -38,6 +47,7 @@ for f in `git diff --name-only FETCH_HEAD... -- changelog.d`; do
    lastchar=`tr -d '\n' < $f | tail -c 1`
    if [ $lastchar != '.' -a $lastchar != '!' ]; then
        echo -e "\e[31mERROR: newsfragment $f does not end with a '.' or '!'\e[39m" >&2
+        echo -e "$CONTRIBUTING_GUIDE_TEXT" >&2
        exit 1
    fi

@@ -47,5 +57,6 @@ done

 if [[ -n "$pr" && "$matched" -eq 0 ]]; then
    echo -e "\e[31mERROR: Did not find a news fragment with the right number: expected changelog.d/$pr.*.\e[39m" >&2
+    echo -e "$CONTRIBUTING_GUIDE_TEXT" >&2
    exit 1
 fi
--- a/scripts-dev/check_line_terminators.sh
+++ b/scripts-dev/check_line_terminators.sh
@@ -0,0 +1,34 @@
+#!/bin/bash
+#
+# 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 script checks that line terminators in all repository files (excluding
+# those in the .git directory) feature unix line terminators.
+#
+# Usage:
+#
+# ./check_line_terminators.sh
+#
+# The script will emit exit code 1 if any files that do not use unix line
+# terminators are found, 0 otherwise.
+
+# cd to the root of the repository
+cd `dirname $0`/..
+
+# Find and print files with non-unix line terminators
+if find . -path './.git/*' -prune -o -type f -print0 | xargs -0 grep -I -l $'\r$'; then
+    echo -e '\e[31mERROR: found files with CRLF line endings. See above.\e[39m'
+    exit 1
+fi
--- a/scripts-dev/update_database
+++ b/scripts-dev/update_database
@@ -40,7 +40,7 @@ class MockHomeserver(HomeServer):
            config.server_name, reactor=reactor, config=config, **kwargs
        )

-        self.version_string = "Synapse/"+get_version_string(synapse)
+        self.version_string = "Synapse/" + get_version_string(synapse)


 if __name__ == "__main__":
@@ -86,7 +86,7 @@ if __name__ == "__main__":
    store = hs.get_datastore()

    async def run_background_updates():
-        await store.db.updates.run_background_updates(sleep=False)
+        await store.db_pool.updates.run_background_updates(sleep=False)
        # Stop the reactor to exit the script once every background update is run.
        reactor.stop()

--- a/scripts/synapse_port_db
+++ b/scripts/synapse_port_db
@@ -35,31 +35,29 @@ from synapse.logging.context import (
    make_deferred_yieldable,
    run_in_background,
 )
-from synapse.storage.data_stores.main.client_ips import ClientIpBackgroundUpdateStore
-from synapse.storage.data_stores.main.deviceinbox import (
-    DeviceInboxBackgroundUpdateStore,
-)
-from synapse.storage.data_stores.main.devices import DeviceBackgroundUpdateStore
-from synapse.storage.data_stores.main.events_bg_updates import (
+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.events_bg_updates import (
    EventsBackgroundUpdatesStore,
 )
-from synapse.storage.data_stores.main.media_repository import (
+from synapse.storage.databases.main.media_repository import (
    MediaRepositoryBackgroundUpdateStore,
 )
-from synapse.storage.data_stores.main.registration import (
+from synapse.storage.databases.main.registration import (
    RegistrationBackgroundUpdateStore,
    find_max_generated_user_id_localpart,
 )
-from synapse.storage.data_stores.main.room import RoomBackgroundUpdateStore
-from synapse.storage.data_stores.main.roommember import RoomMemberBackgroundUpdateStore
-from synapse.storage.data_stores.main.search import SearchBackgroundUpdateStore
-from synapse.storage.data_stores.main.state import MainStateBackgroundUpdateStore
-from synapse.storage.data_stores.main.stats import StatsStore
-from synapse.storage.data_stores.main.user_directory import (
+from synapse.storage.databases.main.room import RoomBackgroundUpdateStore
+from synapse.storage.databases.main.roommember import RoomMemberBackgroundUpdateStore
+from synapse.storage.databases.main.search import SearchBackgroundUpdateStore
+from synapse.storage.databases.main.state import MainStateBackgroundUpdateStore
+from synapse.storage.databases.main.stats import StatsStore
+from synapse.storage.databases.main.user_directory import (
    UserDirectoryBackgroundUpdateStore,
 )
-from synapse.storage.data_stores.state.bg_updates import StateBackgroundUpdateStore
-from synapse.storage.database import Database, make_conn
+from synapse.storage.databases.state.bg_updates import StateBackgroundUpdateStore
 from synapse.storage.engines import create_engine
 from synapse.storage.prepare_database import prepare_database
 from synapse.util import Clock
@@ -175,14 +173,14 @@ class Store(
    StatsStore,
 ):
    def execute(self, f, *args, **kwargs):
-        return self.db.runInteraction(f.__name__, f, *args, **kwargs)
+        return self.db_pool.runInteraction(f.__name__, f, *args, **kwargs)

    def execute_sql(self, sql, *args):
        def r(txn):
            txn.execute(sql, args)
            return txn.fetchall()

-        return self.db.runInteraction("execute_sql", r)
+        return self.db_pool.runInteraction("execute_sql", r)

    def insert_many_txn(self, txn, table, headers, rows):
        sql = "INSERT INTO %s (%s) VALUES (%s)" % (
@@ -227,7 +225,7 @@ class Porter(object):
    async def setup_table(self, table):
        if table in APPEND_ONLY_TABLES:
            # It's safe to just carry on inserting.
-            row = await self.postgres_store.db.simple_select_one(
+            row = await self.postgres_store.db_pool.simple_select_one(
                table="port_from_sqlite3",
                keyvalues={"table_name": table},
                retcols=("forward_rowid", "backward_rowid"),
@@ -244,7 +242,7 @@ class Porter(object):
                    ) = await self._setup_sent_transactions()
                    backward_chunk = 0
                else:
-                    await self.postgres_store.db.simple_insert(
+                    await self.postgres_store.db_pool.simple_insert(
                        table="port_from_sqlite3",
                        values={
                            "table_name": table,
@@ -274,7 +272,7 @@ class Porter(object):

            await self.postgres_store.execute(delete_all)

-            await self.postgres_store.db.simple_insert(
+            await self.postgres_store.db_pool.simple_insert(
                table="port_from_sqlite3",
                values={"table_name": table, "forward_rowid": 1, "backward_rowid": 0},
            )
@@ -318,7 +316,7 @@ class Porter(object):
        if table == "user_directory_stream_pos":
            # We need to make sure there is a single row, `(X, null), as that is
            # what synapse expects to be there.
-            await self.postgres_store.db.simple_insert(
+            await self.postgres_store.db_pool.simple_insert(
                table=table, values={"stream_id": None}
            )
            self.progress.update(table, table_size)  # Mark table as done
@@ -359,7 +357,7 @@ class Porter(object):

                return headers, forward_rows, backward_rows

-            headers, frows, brows = await self.sqlite_store.db.runInteraction(
+            headers, frows, brows = await self.sqlite_store.db_pool.runInteraction(
                "select", r
            )

@@ -375,7 +373,7 @@ class Porter(object):
                def insert(txn):
                    self.postgres_store.insert_many_txn(txn, table, headers[1:], rows)

-                    self.postgres_store.db.simple_update_one_txn(
+                    self.postgres_store.db_pool.simple_update_one_txn(
                        txn,
                        table="port_from_sqlite3",
                        keyvalues={"table_name": table},
@@ -413,7 +411,7 @@ class Porter(object):

                return headers, rows

-            headers, rows = await self.sqlite_store.db.runInteraction("select", r)
+            headers, rows = await self.sqlite_store.db_pool.runInteraction("select", r)

            if rows:
                forward_chunk = rows[-1][0] + 1
@@ -451,7 +449,7 @@ class Porter(object):
                        ],
                    )

-                    self.postgres_store.db.simple_update_one_txn(
+                    self.postgres_store.db_pool.simple_update_one_txn(
                        txn,
                        table="port_from_sqlite3",
                        keyvalues={"table_name": "event_search"},
@@ -494,7 +492,7 @@ class Porter(object):
                db_conn, allow_outdated_version=allow_outdated_version
            )
            prepare_database(db_conn, engine, config=self.hs_config)
-            store = Store(Database(hs, db_config, engine), db_conn, hs)
+            store = Store(DatabasePool(hs, db_config, engine), db_conn, hs)
            db_conn.commit()

        return store
@@ -502,7 +500,7 @@ class Porter(object):
    async def run_background_updates_on_postgres(self):
        # Manually apply all background updates on the PostgreSQL database.
        postgres_ready = (
-            await self.postgres_store.db.updates.has_completed_background_updates()
+            await self.postgres_store.db_pool.updates.has_completed_background_updates()
        )

        if not postgres_ready:
@@ -511,9 +509,9 @@ class Porter(object):
            self.progress.set_state("Running background updates on PostgreSQL")

        while not postgres_ready:
-            await self.postgres_store.db.updates.do_next_background_update(100)
+            await self.postgres_store.db_pool.updates.do_next_background_update(100)
            postgres_ready = await (
-                self.postgres_store.db.updates.has_completed_background_updates()
+                self.postgres_store.db_pool.updates.has_completed_background_updates()
            )

    async def run(self):
@@ -534,7 +532,7 @@ class Porter(object):

            # Check if all background updates are done, abort if not.
            updates_complete = (
-                await self.sqlite_store.db.updates.has_completed_background_updates()
+                await self.sqlite_store.db_pool.updates.has_completed_background_updates()
            )
            if not updates_complete:
                end_error = (
@@ -576,22 +574,24 @@ class Porter(object):
                )

            try:
-                await self.postgres_store.db.runInteraction("alter_table", alter_table)
+                await self.postgres_store.db_pool.runInteraction(
+                    "alter_table", alter_table
+                )
            except Exception:
                # On Error Resume Next
                pass

-            await self.postgres_store.db.runInteraction(
+            await self.postgres_store.db_pool.runInteraction(
                "create_port_table", create_port_table
            )

            # Step 2. Get tables.
            self.progress.set_state("Fetching tables")
-            sqlite_tables = await self.sqlite_store.db.simple_select_onecol(
+            sqlite_tables = await self.sqlite_store.db_pool.simple_select_onecol(
                table="sqlite_master", keyvalues={"type": "table"}, retcol="name"
            )

-            postgres_tables = await self.postgres_store.db.simple_select_onecol(
+            postgres_tables = await self.postgres_store.db_pool.simple_select_onecol(
                table="information_schema.tables",
                keyvalues={},
                retcol="distinct table_name",
@@ -692,7 +692,7 @@ class Porter(object):

            return headers, [r for r in rows if r[ts_ind] < yesterday]

-        headers, rows = await self.sqlite_store.db.runInteraction("select", r)
+        headers, rows = await self.sqlite_store.db_pool.runInteraction("select", r)

        rows = self._convert_rows("sent_transactions", headers, rows)

@@ -725,7 +725,7 @@ class Porter(object):
        next_chunk = await self.sqlite_store.execute(get_start_id)
        next_chunk = max(max_inserted_rowid + 1, next_chunk)

-        await self.postgres_store.db.simple_insert(
+        await self.postgres_store.db_pool.simple_insert(
            table="port_from_sqlite3",
            values={
                "table_name": "sent_transactions",
@@ -794,14 +794,14 @@ class Porter(object):
            next_id = curr_id + 1
            txn.execute("ALTER SEQUENCE state_group_id_seq RESTART WITH %s", (next_id,))

-        return self.postgres_store.db.runInteraction("setup_state_group_id_seq", r)
+        return self.postgres_store.db_pool.runInteraction("setup_state_group_id_seq", r)

    def _setup_user_id_seq(self):
        def r(txn):
            next_id = find_max_generated_user_id_localpart(txn) + 1
            txn.execute("ALTER SEQUENCE user_id_seq RESTART WITH %s", (next_id,))

-        return self.postgres_store.db.runInteraction("setup_user_id_seq", r)
+        return self.postgres_store.db_pool.runInteraction("setup_user_id_seq", r)


 ##############################################
--- a/synapse/init.py
+++ b/synapse/init.py
@@ -17,6 +17,7 @@
 """ This is a reference implementation of a Matrix homeserver.
 """

+import json
 import os
 import sys

@@ -25,6 +26,9 @@ if sys.version_info < (3, 5):
    print("Synapse requires Python 3.5 or above.")
    sys.exit(1)

+# Twisted and canonicaljson will fail to import when this file is executed to
+# get the __version__ during a fresh install. That's OK and subsequent calls to
+# actually start Synapse will import these libraries fine.
 try:
    from twisted.internet import protocol
    from twisted.internet.protocol import Factory
@@ -36,7 +40,15 @@ try:
 except ImportError:
    pass

-__version__ = "1.18.0"
+# Use the standard library json implementation instead of simplejson.
+try:
+    from canonicaljson import set_json_library
+
+    set_json_library(json)
+except ImportError:
+    pass
+
+__version__ = "1.19.0"

 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
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -13,12 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import Optional
+from typing import List, Optional, Tuple

 import pymacaroons
 from netaddr import IPAddress

-from twisted.internet import defer
 from twisted.web.server import Request

 import synapse.types
@@ -80,13 +79,14 @@ class Auth(object):
        self._track_appservice_user_ips = hs.config.track_appservice_user_ips
        self._macaroon_secret_key = hs.config.macaroon_secret_key

-    @defer.inlineCallbacks
-    def check_from_context(self, room_version: str, event, context, do_sig_check=True):
-        prev_state_ids = yield context.get_prev_state_ids()
-        auth_events_ids = yield self.compute_auth_events(
+    async def check_from_context(
+        self, room_version: str, event, context, do_sig_check=True
+    ):
+        prev_state_ids = await context.get_prev_state_ids()
+        auth_events_ids = self.compute_auth_events(
            event, prev_state_ids, for_verification=True
        )
-        auth_events = yield self.store.get_events(auth_events_ids)
+        auth_events = await self.store.get_events(auth_events_ids)
        auth_events = {(e.type, e.state_key): e for e in auth_events.values()}

        room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
@@ -94,14 +94,13 @@ class Auth(object):
            room_version_obj, event, auth_events=auth_events, do_sig_check=do_sig_check
        )

-    @defer.inlineCallbacks
-    def check_user_in_room(
+    async def check_user_in_room(
        self,
        room_id: str,
        user_id: str,
        current_state: Optional[StateMap[EventBase]] = None,
        allow_departed_users: bool = False,
-    ):
+    ) -> EventBase:
        """Check if the user is in the room, or was at some point.
        Args:
            room_id: The room to check.
@@ -119,37 +118,35 @@ class Auth(object):
        Raises:
            AuthError if the user is/was not in the room.
        Returns:
-            Deferred[Optional[EventBase]]:
-                Membership event for the user if the user was in the
-                room. This will be the join event if they are currently joined to
-                the room. This will be the leave event if they have left the room.
+            Membership event for the user if the user was in the
+            room. This will be the join event if they are currently joined to
+            the room. This will be the leave event if they have left the room.
        """
        if current_state:
            member = current_state.get((EventTypes.Member, user_id), None)
        else:
-            member = yield defer.ensureDeferred(
-                self.state.get_current_state(
-                    room_id=room_id, event_type=EventTypes.Member, state_key=user_id
-                )
+            member = await self.state.get_current_state(
+                room_id=room_id, event_type=EventTypes.Member, state_key=user_id
            )
-        membership = member.membership if member else None

-        if membership == Membership.JOIN:
-            return member
+        if member:
+            membership = member.membership

-        # XXX this looks totally bogus. Why do we not allow users who have been banned,
-        # or those who were members previously and have been re-invited?
-        if allow_departed_users and membership == Membership.LEAVE:
-            forgot = yield self.store.did_forget(user_id, room_id)
-            if not forgot:
+            if membership == Membership.JOIN:
                return member

+            # XXX this looks totally bogus. Why do we not allow users who have been banned,
+            # or those who were members previously and have been re-invited?
+            if allow_departed_users and membership == Membership.LEAVE:
+                forgot = await self.store.did_forget(user_id, room_id)
+                if not forgot:
+                    return member
+
        raise AuthError(403, "User %s not in room %s" % (user_id, room_id))

-    @defer.inlineCallbacks
-    def check_host_in_room(self, room_id, host):
+    async def check_host_in_room(self, room_id, host):
        with Measure(self.clock, "check_host_in_room"):
-            latest_event_ids = yield self.store.is_host_joined(room_id, host)
+            latest_event_ids = await self.store.is_host_joined(room_id, host)
            return latest_event_ids

    def can_federate(self, event, auth_events):
@@ -160,14 +157,13 @@ class Auth(object):
    def get_public_keys(self, invite_event):
        return event_auth.get_public_keys(invite_event)

-    @defer.inlineCallbacks
-    def get_user_by_req(
+    async def get_user_by_req(
        self,
        request: Request,
        allow_guest: bool = False,
        rights: str = "access",
        allow_expired: bool = False,
-    ):
+    ) -> synapse.types.Requester:
        """ Get a registered user's ID.

        Args:
@@ -180,7 +176,7 @@ class Auth(object):
                /login will deliver access tokens regardless of expiration.

        Returns:
-            defer.Deferred: resolves to a `synapse.types.Requester` object
+            Resolves to the requester
        Raises:
            InvalidClientCredentialsError if no user by that token exists or the token
                is invalid.
@@ -194,14 +190,14 @@ class Auth(object):

            access_token = self.get_access_token_from_request(request)

-            user_id, app_service = yield self._get_appservice_user_id(request)
+            user_id, app_service = await 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:
-                    yield self.store.insert_client_ip(
+                    await self.store.insert_client_ip(
                        user_id=user_id,
                        access_token=access_token,
                        ip=ip_addr,
@@ -211,17 +207,18 @@ class Auth(object):

                return synapse.types.create_requester(user_id, app_service=app_service)

-            user_info = yield self.get_user_by_access_token(
+            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"]

            # Deny the request if the user account has expired.
            if self._account_validity.enabled and not allow_expired:
                user_id = user.to_string()
-                expiration_ts = yield self.store.get_expiration_ts_for_user(user_id)
+                expiration_ts = await self.store.get_expiration_ts_for_user(user_id)
                if (
                    expiration_ts is not None
                    and self.clock.time_msec() >= expiration_ts
@@ -235,7 +232,7 @@ class Auth(object):
            device_id = user_info.get("device_id")

            if user and access_token and ip_addr:
-                yield self.store.insert_client_ip(
+                await self.store.insert_client_ip(
                    user_id=user.to_string(),
                    access_token=access_token,
                    ip=ip_addr,
@@ -256,13 +253,17 @@ class Auth(object):
                opentracing.set_tag("device_id", device_id)

            return synapse.types.create_requester(
-                user, token_id, is_guest, device_id, app_service=app_service
+                user,
+                token_id,
+                is_guest,
+                shadow_banned,
+                device_id,
+                app_service=app_service,
            )
        except KeyError:
            raise MissingClientTokenError()

-    @defer.inlineCallbacks
-    def _get_appservice_user_id(self, request):
+    async def _get_appservice_user_id(self, request):
        app_service = self.store.get_app_service_by_token(
            self.get_access_token_from_request(request)
        )
@@ -283,14 +284,13 @@ class Auth(object):

        if not app_service.is_interested_in_user(user_id):
            raise AuthError(403, "Application service cannot masquerade as this user.")
-        if not (yield self.store.get_user_by_id(user_id)):
+        if not (await self.store.get_user_by_id(user_id)):
            raise AuthError(403, "Application service has not registered this user")
        return user_id, app_service

-    @defer.inlineCallbacks
-    def get_user_by_access_token(
+    async def get_user_by_access_token(
        self, token: str, rights: str = "access", allow_expired: bool = False,
-    ):
+    ) -> dict:
        """ Validate access token and get user_id from it

        Args:
@@ -300,9 +300,10 @@ class Auth(object):
            allow_expired: If False, raises an InvalidClientTokenError
                if the token is expired
        Returns:
-            Deferred[dict]: dict that includes:
+            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:
@@ -314,7 +315,7 @@ class Auth(object):

        if rights == "access":
            # first look in the database
-            r = yield self._look_up_user_by_access_token(token)
+            r = await self._look_up_user_by_access_token(token)
            if r:
                valid_until_ms = r["valid_until_ms"]
                if (
@@ -352,7 +353,7 @@ class Auth(object):
                # It would of course be much easier to store guest access
                # tokens in the database as well, but that would break existing
                # guest tokens.
-                stored_user = yield self.store.get_user_by_id(user_id)
+                stored_user = await self.store.get_user_by_id(user_id)
                if not stored_user:
                    raise InvalidClientTokenError("Unknown user_id %s" % user_id)
                if not stored_user["is_guest"]:
@@ -362,6 +363,7 @@ class Auth(object):
                ret = {
                    "user": user,
                    "is_guest": True,
+                    "shadow_banned": False,
                    "token_id": None,
                    # all guests get the same device id
                    "device_id": GUEST_DEVICE_ID,
@@ -371,6 +373,7 @@ class Auth(object):
                ret = {
                    "user": user,
                    "is_guest": False,
+                    "shadow_banned": False,
                    "token_id": None,
                    "device_id": None,
                }
@@ -482,9 +485,8 @@ class Auth(object):
        now = self.hs.get_clock().time_msec()
        return now < expiry

-    @defer.inlineCallbacks
-    def _look_up_user_by_access_token(self, token):
-        ret = yield self.store.get_user_by_access_token(token)
+    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

@@ -495,6 +497,7 @@ class Auth(object):
            "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"),
        }
@@ -507,7 +510,7 @@ class Auth(object):
            logger.warning("Unrecognised appservice access token.")
            raise InvalidClientTokenError()
        request.authenticated_entity = service.sender
-        return defer.succeed(service)
+        return service

    async def is_server_admin(self, user: UserID) -> bool:
        """ Check if the given user is a local server admin.
@@ -522,7 +525,7 @@ class Auth(object):

    def compute_auth_events(
        self, event, current_state_ids: StateMap[str], for_verification: bool = False,
-    ):
+    ) -> List[str]:
        """Given an event and current state return the list of event IDs used
        to auth an event.

@@ -530,11 +533,11 @@ class Auth(object):
        should be added to the event's `auth_events`.

        Returns:
-            defer.Deferred(list[str]): List of event IDs.
+            List of event IDs.
        """

        if event.type == EventTypes.Create:
-            return defer.succeed([])
+            return []

        # Currently we ignore the `for_verification` flag even though there are
        # some situations where we can drop particular auth events when adding
@@ -553,7 +556,7 @@ class Auth(object):
            if auth_ev_id:
                auth_ids.append(auth_ev_id)

-        return defer.succeed(auth_ids)
+        return auth_ids

    async def check_can_change_room_list(self, room_id: str, user: UserID):
        """Determine whether the user is allowed to edit the room's entry in the
@@ -636,10 +639,9 @@ class Auth(object):

            return query_params[0].decode("ascii")

-    @defer.inlineCallbacks
-    def check_user_in_room_or_world_readable(
+    async def check_user_in_room_or_world_readable(
        self, room_id: str, user_id: str, allow_departed_users: bool = False
-    ):
+    ) -> Tuple[str, Optional[str]]:
        """Checks that the user is or was in the room or the room is world
        readable. If it isn't then an exception is raised.

@@ -650,10 +652,9 @@ class Auth(object):
                members but have now departed

        Returns:
-            Deferred[tuple[str, str|None]]: Resolves to the current membership of
-                the user in the room and the membership event ID of the user. If
-                the user is not in the room and never has been, then
-                `(Membership.JOIN, None)` is returned.
+            Resolves to the current membership of the user in the room and the
+            membership event ID of the user. If the user is not in the room and
+            never has been, then `(Membership.JOIN, None)` is returned.
        """

        try:
@@ -662,15 +663,13 @@ class Auth(object):
            #  * The user is a non-guest user, and was ever in the room
            #  * The user is a guest user, and has joined the room
            # else it will throw.
-            member_event = yield self.check_user_in_room(
+            member_event = await self.check_user_in_room(
                room_id, user_id, allow_departed_users=allow_departed_users
            )
            return member_event.membership, member_event.event_id
        except AuthError:
-            visibility = yield defer.ensureDeferred(
-                self.state.get_current_state(
-                    room_id, EventTypes.RoomHistoryVisibility, ""
-                )
+            visibility = await self.state.get_current_state(
+                room_id, EventTypes.RoomHistoryVisibility, ""
            )
            if (
                visibility
--- a/synapse/api/auth_blocking.py
+++ b/synapse/api/auth_blocking.py
@@ -15,8 +15,6 @@

 import logging

-from twisted.internet import defer
-
 from synapse.api.constants import LimitBlockingTypes, UserTypes
 from synapse.api.errors import Codes, ResourceLimitError
 from synapse.config.server import is_threepid_reserved
@@ -36,8 +34,7 @@ class AuthBlocking(object):
        self._limit_usage_by_mau = hs.config.limit_usage_by_mau
        self._mau_limits_reserved_threepids = hs.config.mau_limits_reserved_threepids

-    @defer.inlineCallbacks
-    def check_auth_blocking(self, user_id=None, threepid=None, user_type=None):
+    async def check_auth_blocking(self, user_id=None, threepid=None, user_type=None):
        """Checks if the user should be rejected for some external reason,
        such as monthly active user limiting or global disable flag

@@ -60,7 +57,7 @@ class AuthBlocking(object):
        if user_id is not None:
            if user_id == self._server_notices_mxid:
                return
-            if (yield self.store.is_support_user(user_id)):
+            if await self.store.is_support_user(user_id):
                return

        if self._hs_disabled:
@@ -76,11 +73,11 @@ class AuthBlocking(object):

            # If the user is already part of the MAU cohort or a trial user
            if user_id:
-                timestamp = yield self.store.user_last_seen_monthly_active(user_id)
+                timestamp = await self.store.user_last_seen_monthly_active(user_id)
                if timestamp:
                    return

-                is_trial = yield self.store.is_trial_user(user_id)
+                is_trial = await self.store.is_trial_user(user_id)
                if is_trial:
                    return
            elif threepid:
@@ -93,7 +90,7 @@ class AuthBlocking(object):
                # allow registration. Support users are excluded from MAU checks.
                return
            # Else if there is no room in the MAU bucket, bail
-            current_mau = yield self.store.get_monthly_active_count()
+            current_mau = await self.store.get_monthly_active_count()
            if current_mau >= self._max_mau_value:
                raise ResourceLimitError(
                    403,
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -238,14 +238,16 @@ class InteractiveAuthIncompleteError(Exception):
    (This indicates we should return a 401 with 'result' as the body)

    Attributes:
+        session_id: The ID of the ongoing interactive auth session.
        result: the server response to the request, which should be
            passed back to the client
    """

-    def __init__(self, result: "JsonDict"):
+    def __init__(self, session_id: str, result: "JsonDict"):
        super(InteractiveAuthIncompleteError, self).__init__(
            "Interactive auth not yet complete"
        )
+        self.session_id = session_id
        self.result = result


--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -21,11 +21,9 @@ import jsonschema
 from canonicaljson import json
 from jsonschema import FormatChecker

-from twisted.internet import defer
-
 from synapse.api.constants import EventContentFields
 from synapse.api.errors import SynapseError
-from synapse.storage.presence import UserPresenceState
+from synapse.api.presence import UserPresenceState
 from synapse.types import RoomID, UserID

 FILTER_SCHEMA = {
@@ -137,9 +135,8 @@ class Filtering(object):
        super(Filtering, self).__init__()
        self.store = hs.get_datastore()

-    @defer.inlineCallbacks
-    def get_user_filter(self, user_localpart, filter_id):
-        result = yield self.store.get_user_filter(user_localpart, filter_id)
+    async def get_user_filter(self, user_localpart, filter_id):
+        result = await self.store.get_user_filter(user_localpart, filter_id)
        return FilterCollection(result)

    def add_user_filter(self, user_localpart, user_filter):
--- a/synapse/storage/presence.py
+++ b/synapse/storage/presence.py
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.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 gc
 import logging
 import os
@@ -22,7 +21,6 @@ import sys
 import traceback
 from typing import Iterable

-from daemonize import Daemonize
 from typing_extensions import NoReturn

 from twisted.internet import defer, error, reactor
@@ -34,6 +32,7 @@ from synapse.config.server import ListenerConfig
 from synapse.crypto import context_factory
 from synapse.logging.context import PreserveLoggingContext
 from synapse.util.async_helpers import Linearizer
+from synapse.util.daemonize import daemonize_process
 from synapse.util.rlimit import change_resource_limit
 from synapse.util.versionstring import get_version_string

@@ -129,17 +128,8 @@ def start_reactor(
            if print_pidfile:
                print(pid_file)

-            daemon = Daemonize(
-                app=appname,
-                pid=pid_file,
-                action=run,
-                auto_close_fds=False,
-                verbose=True,
-                logger=logger,
-            )
-            daemon.start()
-        else:
-            run()
+            daemonize_process(pid_file, logger)
+        run()


 def quit_with_error(error_string: str) -> NoReturn:
@@ -278,7 +268,7 @@ def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]):

        # It is now safe to start your Synapse.
        hs.start_listening(listeners)
-        hs.get_datastore().db.start_profiling()
+        hs.get_datastore().db_pool.start_profiling()
        hs.get_pusherpool().start()

        setup_sentry(hs)
--- a/synapse/app/generic_worker.py
+++ b/synapse/app/generic_worker.py
@@ -123,17 +123,18 @@ from synapse.rest.client.v2_alpha.account_data import (
 from synapse.rest.client.v2_alpha.keys import KeyChangesServlet, KeyQueryServlet
 from synapse.rest.client.v2_alpha.register import RegisterRestServlet
 from synapse.rest.client.versions import VersionsRestServlet
+from synapse.rest.health import HealthResource
 from synapse.rest.key.v2 import KeyApiV2Resource
-from synapse.server import HomeServer
-from synapse.storage.data_stores.main.censor_events import CensorEventsStore
-from synapse.storage.data_stores.main.media_repository import MediaRepositoryStore
-from synapse.storage.data_stores.main.monthly_active_users import (
+from synapse.server import HomeServer, cache_in_self
+from synapse.storage.databases.main.censor_events import CensorEventsStore
+from synapse.storage.databases.main.media_repository import MediaRepositoryStore
+from synapse.storage.databases.main.monthly_active_users import (
    MonthlyActiveUsersWorkerStore,
 )
-from synapse.storage.data_stores.main.presence import UserPresenceState
-from synapse.storage.data_stores.main.search import SearchWorkerStore
-from synapse.storage.data_stores.main.ui_auth import UIAuthWorkerStore
-from synapse.storage.data_stores.main.user_directory import UserDirectoryStore
+from synapse.storage.databases.main.presence import UserPresenceState
+from synapse.storage.databases.main.search import SearchWorkerStore
+from synapse.storage.databases.main.ui_auth import UIAuthWorkerStore
+from synapse.storage.databases.main.user_directory import UserDirectoryStore
 from synapse.types import ReadReceipt
 from synapse.util.async_helpers import Linearizer
 from synapse.util.httpresourcetree import create_resource_tree
@@ -493,7 +494,10 @@ class GenericWorkerServer(HomeServer):
        site_tag = listener_config.http_options.tag
        if site_tag is None:
            site_tag = port
-        resources = {}
+
+        # We always include a health resource.
+        resources = {"/health": HealthResource()}
+
        for res in listener_config.http_options.resources:
            for name in res.names:
                if name == "metrics":
@@ -628,13 +632,15 @@ class GenericWorkerServer(HomeServer):

        self.get_tcp_replication().start_replication(self)

-    def remove_pusher(self, app_id, push_key, user_id):
+    async def remove_pusher(self, app_id, push_key, user_id):
        self.get_tcp_replication().send_remove_pusher(app_id, push_key, user_id)

-    def build_replication_data_handler(self):
+    @cache_in_self
+    def get_replication_data_handler(self):
        return GenericWorkerReplicationHandler(self)

-    def build_presence_handler(self):
+    @cache_in_self
+    def get_presence_handler(self):
        return GenericWorkerPresence(self)


--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -68,6 +68,7 @@ from synapse.replication.http import REPLICATION_PREFIX, ReplicationRestResource
 from synapse.replication.tcp.resource import ReplicationStreamProtocolFactory
 from synapse.rest import ClientRestResource
 from synapse.rest.admin import AdminRestResource
+from synapse.rest.health import HealthResource
 from synapse.rest.key.v2 import KeyApiV2Resource
 from synapse.rest.well_known import WellKnownResource
 from synapse.server import HomeServer
@@ -98,7 +99,9 @@ class SynapseHomeServer(HomeServer):
        if site_tag is None:
            site_tag = port

-        resources = {}
+        # We always include a health resource.
+        resources = {"/health": HealthResource()}
+
        for res in listener_config.http_options.resources:
            for name in res.names:
                if name == "openid" and "federation" in res.names:
@@ -380,13 +383,12 @@ def setup(config_options):

    hs.setup_master()

-    @defer.inlineCallbacks
-    def do_acme():
+    async def do_acme() -> bool:
        """
        Reprovision an ACME certificate, if it's required.

        Returns:
-            Deferred[bool]: Whether the cert has been updated.
+            Whether the cert has been updated.
        """
        acme = hs.get_acme_handler()

@@ -405,7 +407,7 @@ def setup(config_options):
            provision = True

        if provision:
-            yield acme.provision_certificate()
+            await acme.provision_certificate()

        return provision

@@ -415,7 +417,7 @@ def setup(config_options):
        Provision a certificate from ACME, if required, and reload the TLS
        certificate if it's renewed.
        """
-        reprovisioned = yield do_acme()
+        reprovisioned = yield defer.ensureDeferred(do_acme())
        if reprovisioned:
            _base.refresh_certificate(hs)

@@ -427,8 +429,8 @@ def setup(config_options):
                acme = hs.get_acme_handler()
                # Start up the webservices which we will respond to ACME
                # challenges with, and then provision.
-                yield acme.start_listening()
-                yield do_acme()
+                yield defer.ensureDeferred(acme.start_listening())
+                yield defer.ensureDeferred(do_acme())

                # Check if it needs to be reprovisioned every day.
                hs.get_clock().looping_call(reprovision_acme, 24 * 60 * 60 * 1000)
@@ -442,7 +444,7 @@ def setup(config_options):

            _base.start(hs, config.listeners)

-            hs.get_datastore().db.updates.start_doing_background_updates()
+            hs.get_datastore().db_pool.updates.start_doing_background_updates()
        except Exception:
            # Print the exception and bail out.
            print("Error during startup:", file=sys.stderr)
@@ -552,8 +554,8 @@ async def phone_stats_home(hs, stats, stats_process=_stats_process):
    #

    # This only reports info about the *main* database.
-    stats["database_engine"] = hs.get_datastore().db.engine.module.__name__
-    stats["database_server_version"] = hs.get_datastore().db.engine.server_version
+    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:
--- a/synapse/appservice/init.py
+++ b/synapse/appservice/init.py
@@ -15,11 +15,9 @@
 import logging
 import re

-from twisted.internet import defer
-
 from synapse.api.constants import EventTypes
 from synapse.types import GroupID, get_domain_from_id
-from synapse.util.caches.descriptors import cachedInlineCallbacks
+from synapse.util.caches.descriptors import cached

 logger = logging.getLogger(__name__)

@@ -43,7 +41,7 @@ class AppServiceTransaction(object):
        Args:
            as_api(ApplicationServiceApi): The API to use to send.
        Returns:
-            A Deferred which resolves to True if the transaction was sent.
+            An Awaitable which resolves to True if the transaction was sent.
        """
        return as_api.push_bulk(
            service=self.service, events=self.events, txn_id=self.id
@@ -172,8 +170,7 @@ class ApplicationService(object):
            return regex_obj["exclusive"]
        return False

-    @defer.inlineCallbacks
-    def _matches_user(self, event, store):
+    async def _matches_user(self, event, store):
        if not event:
            return False

@@ -188,12 +185,12 @@ class ApplicationService(object):
        if not store:
            return False

-        does_match = yield 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

-    @cachedInlineCallbacks(num_args=1, cache_context=True)
-    def _matches_user_in_member_list(self, room_id, store, cache_context):
-        member_list = yield store.get_users_in_room(
+    @cached(num_args=1, cache_context=True)
+    async def _matches_user_in_member_list(self, room_id, store, cache_context):
+        member_list = await store.get_users_in_room(
            room_id, on_invalidate=cache_context.invalidate
        )

@@ -208,35 +205,33 @@ class ApplicationService(object):
            return self.is_interested_in_room(event.room_id)
        return False

-    @defer.inlineCallbacks
-    def _matches_aliases(self, event, store):
+    async def _matches_aliases(self, event, store):
        if not store or not event:
            return False

-        alias_list = yield store.get_aliases_for_room(event.room_id)
+        alias_list = await store.get_aliases_for_room(event.room_id)
        for alias in alias_list:
            if self.is_interested_in_alias(alias):
                return True
        return False

-    @defer.inlineCallbacks
-    def is_interested(self, event, store=None):
+    async def is_interested(self, event, store=None) -> bool:
        """Check if this service is interested in this event.

        Args:
            event(Event): The event to check.
            store(DataStore)
        Returns:
-            bool: True if this service would like to know about this event.
+            True if this service would like to know about this event.
        """
        # Do cheap checks first
        if self._matches_room_id(event):
            return True

-        if (yield self._matches_aliases(event, store)):
+        if await self._matches_aliases(event, store):
            return True

-        if (yield self._matches_user(event, store)):
+        if await self._matches_user(event, store):
            return True

        return False
--- a/synapse/appservice/api.py
+++ b/synapse/appservice/api.py
@@ -93,13 +93,12 @@ class ApplicationServiceApi(SimpleHttpClient):
            hs, "as_protocol_meta", timeout_ms=HOUR_IN_MS
        )

-    @defer.inlineCallbacks
-    def query_user(self, service, user_id):
+    async def query_user(self, service, user_id):
        if service.url is None:
            return False
        uri = service.url + ("/users/%s" % urllib.parse.quote(user_id))
        try:
-            response = yield self.get_json(uri, {"access_token": service.hs_token})
+            response = await self.get_json(uri, {"access_token": service.hs_token})
            if response is not None:  # just an empty json object
                return True
        except CodeMessageException as e:
@@ -110,14 +109,12 @@ class ApplicationServiceApi(SimpleHttpClient):
            logger.warning("query_user to %s threw exception %s", uri, ex)
        return False

-    @defer.inlineCallbacks
-    def query_alias(self, service, alias):
+    async def query_alias(self, service, alias):
        if service.url is None:
            return False
        uri = service.url + ("/rooms/%s" % urllib.parse.quote(alias))
-        response = None
        try:
-            response = yield self.get_json(uri, {"access_token": service.hs_token})
+            response = await self.get_json(uri, {"access_token": service.hs_token})
            if response is not None:  # just an empty json object
                return True
        except CodeMessageException as e:
@@ -128,8 +125,7 @@ class ApplicationServiceApi(SimpleHttpClient):
            logger.warning("query_alias to %s threw exception %s", uri, ex)
        return False

-    @defer.inlineCallbacks
-    def query_3pe(self, service, kind, protocol, fields):
+    async def query_3pe(self, service, kind, protocol, fields):
        if kind == ThirdPartyEntityKind.USER:
            required_field = "userid"
        elif kind == ThirdPartyEntityKind.LOCATION:
@@ -146,7 +142,7 @@ class ApplicationServiceApi(SimpleHttpClient):
            urllib.parse.quote(protocol),
        )
        try:
-            response = yield self.get_json(uri, fields)
+            response = await self.get_json(uri, fields)
            if not isinstance(response, list):
                logger.warning(
                    "query_3pe to %s returned an invalid response %r", uri, response
@@ -179,7 +175,7 @@ class ApplicationServiceApi(SimpleHttpClient):
                urllib.parse.quote(protocol),
            )
            try:
-                info = yield self.get_json(uri, {})
+                info = yield defer.ensureDeferred(self.get_json(uri, {}))

                if not _is_valid_3pe_metadata(info):
                    logger.warning(
@@ -202,8 +198,7 @@ class ApplicationServiceApi(SimpleHttpClient):
        key = (service.id, protocol)
        return self.protocol_meta_cache.wrap(key, _get)

-    @defer.inlineCallbacks
-    def push_bulk(self, service, events, txn_id=None):
+    async def push_bulk(self, service, events, txn_id=None):
        if service.url is None:
            return True

@@ -218,7 +213,7 @@ class ApplicationServiceApi(SimpleHttpClient):

        uri = service.url + ("/transactions/%s" % urllib.parse.quote(txn_id))
        try:
-            yield self.put_json(
+            await self.put_json(
                uri=uri,
                json_body={"events": events},
                args={"access_token": service.hs_token},
--- a/synapse/appservice/scheduler.py
+++ b/synapse/appservice/scheduler.py
@@ -50,8 +50,6 @@ components.
 """
 import logging

-from twisted.internet import defer
-
 from synapse.appservice import ApplicationServiceState
 from synapse.logging.context import run_in_background
 from synapse.metrics.background_process_metrics import run_as_background_process
@@ -73,12 +71,11 @@ class ApplicationServiceScheduler(object):
        self.txn_ctrl = _TransactionController(self.clock, self.store, self.as_api)
        self.queuer = _ServiceQueuer(self.txn_ctrl, self.clock)

-    @defer.inlineCallbacks
-    def start(self):
+    async def start(self):
        logger.info("Starting appservice scheduler")

        # check for any DOWN ASes and start recoverers for them.
-        services = yield self.store.get_appservices_by_state(
+        services = await self.store.get_appservices_by_state(
            ApplicationServiceState.DOWN
        )

@@ -117,8 +114,7 @@ class _ServiceQueuer(object):
            "as-sender-%s" % (service.id,), self._send_request, service
        )

-    @defer.inlineCallbacks
-    def _send_request(self, service):
+    async def _send_request(self, service):
        # sanity-check: we shouldn't get here if this service already has a sender
        # running.
        assert service.id not in self.requests_in_flight
@@ -130,7 +126,7 @@ class _ServiceQueuer(object):
                if not events:
                    return
                try:
-                    yield self.txn_ctrl.send(service, events)
+                    await self.txn_ctrl.send(service, events)
                except Exception:
                    logger.exception("AS request failed")
        finally:
@@ -162,36 +158,33 @@ class _TransactionController(object):
        # for UTs
        self.RECOVERER_CLASS = _Recoverer

-    @defer.inlineCallbacks
-    def send(self, service, events):
+    async def send(self, service, events):
        try:
-            txn = yield self.store.create_appservice_txn(service=service, events=events)
-            service_is_up = yield self._is_service_up(service)
+            txn = await self.store.create_appservice_txn(service=service, events=events)
+            service_is_up = await self._is_service_up(service)
            if service_is_up:
-                sent = yield txn.send(self.as_api)
+                sent = await txn.send(self.as_api)
                if sent:
-                    yield txn.complete(self.store)
+                    await txn.complete(self.store)
                else:
                    run_in_background(self._on_txn_fail, service)
        except Exception:
            logger.exception("Error creating appservice transaction")
            run_in_background(self._on_txn_fail, service)

-    @defer.inlineCallbacks
-    def on_recovered(self, recoverer):
+    async def on_recovered(self, recoverer):
        logger.info(
            "Successfully recovered application service AS ID %s", recoverer.service.id
        )
        self.recoverers.pop(recoverer.service.id)
        logger.info("Remaining active recoverers: %s", len(self.recoverers))
-        yield self.store.set_appservice_state(
+        await self.store.set_appservice_state(
            recoverer.service, ApplicationServiceState.UP
        )

-    @defer.inlineCallbacks
-    def _on_txn_fail(self, service):
+    async def _on_txn_fail(self, service):
        try:
-            yield self.store.set_appservice_state(service, ApplicationServiceState.DOWN)
+            await self.store.set_appservice_state(service, ApplicationServiceState.DOWN)
            self.start_recoverer(service)
        except Exception:
            logger.exception("Error starting AS recoverer")
@@ -211,9 +204,8 @@ class _TransactionController(object):
        recoverer.recover()
        logger.info("Now %i active recoverers", len(self.recoverers))

-    @defer.inlineCallbacks
-    def _is_service_up(self, service):
-        state = yield self.store.get_appservice_state(service)
+    async def _is_service_up(self, service):
+        state = await self.store.get_appservice_state(service)
        return state == ApplicationServiceState.UP or state is None


@@ -254,25 +246,24 @@ class _Recoverer(object):
            self.backoff_counter += 1
        self.recover()

-    @defer.inlineCallbacks
-    def retry(self):
+    async def retry(self):
        logger.info("Starting retries on %s", self.service.id)
        try:
            while True:
-                txn = yield self.store.get_oldest_unsent_txn(self.service)
+                txn = await self.store.get_oldest_unsent_txn(self.service)
                if not txn:
                    # nothing left: we're done!
-                    self.callback(self)
+                    await self.callback(self)
                    return

                logger.info(
                    "Retrying transaction %s for AS ID %s", txn.id, txn.service.id
                )
-                sent = yield txn.send(self.as_api)
+                sent = await txn.send(self.as_api)
                if not sent:
                    break

-                yield txn.complete(self.store)
+                await txn.complete(self.store)

                # reset the backoff counter and then process the next transaction
                self.backoff_counter = 1
--- a/synapse/config/_base.py
+++ b/synapse/config/_base.py
@@ -18,12 +18,16 @@
 import argparse
 import errno
 import os
+import time
+import urllib.parse
 from collections import OrderedDict
 from hashlib import sha256
 from textwrap import dedent
-from typing import Any, List, MutableMapping, Optional
+from typing import Any, Callable, List, MutableMapping, Optional

 import attr
+import jinja2
+import pkg_resources
 import yaml


@@ -100,6 +104,11 @@ class Config(object):
    def __init__(self, root_config=None):
        self.root = root_config

+        # Get the path to the default Synapse template directory
+        self.default_template_dir = pkg_resources.resource_filename(
+            "synapse", "res/templates"
+        )
+
    def __getattr__(self, item: str) -> Any:
        """
        Try and fetch a configuration option that does not exist on this class.
@@ -184,6 +193,95 @@ class Config(object):
        with open(file_path) as file_stream:
            return file_stream.read()

+    def read_templates(
+        self, filenames: List[str], custom_template_directory: Optional[str] = None,
+    ) -> List[jinja2.Template]:
+        """Load a list of template files from disk using the given variables.
+
+        This function will attempt to load the given templates from the default Synapse
+        template directory. If `custom_template_directory` is supplied, that directory
+        is tried first.
+
+        Files read are treated as Jinja templates. These templates are not rendered yet.
+
+        Args:
+            filenames: A list of template filenames to read.
+
+            custom_template_directory: A directory to try to look for the templates
+                before using the default Synapse template directory instead.
+
+        Raises:
+            ConfigError: if the file's path is incorrect or otherwise cannot be read.
+
+        Returns:
+            A list of jinja2 templates.
+        """
+        templates = []
+        search_directories = [self.default_template_dir]
+
+        # The loader will first look in the custom template directory (if specified) for the
+        # given filename. If it doesn't find it, it will use the default template dir instead
+        if custom_template_directory:
+            # Check that the given template directory exists
+            if not self.path_exists(custom_template_directory):
+                raise ConfigError(
+                    "Configured template directory does not exist: %s"
+                    % (custom_template_directory,)
+                )
+
+            # Search the custom template directory as well
+            search_directories.insert(0, custom_template_directory)
+
+        loader = jinja2.FileSystemLoader(search_directories)
+        env = jinja2.Environment(loader=loader, autoescape=True)
+
+        # Update the environment with our custom filters
+        env.filters.update(
+            {
+                "format_ts": _format_ts_filter,
+                "mxc_to_http": _create_mxc_to_http_filter(self.public_baseurl),
+            }
+        )
+
+        for filename in filenames:
+            # Load the template
+            template = env.get_template(filename)
+            templates.append(template)
+
+        return templates
+
+
+def _format_ts_filter(value: int, format: str):
+    return time.strftime(format, time.localtime(value / 1000))
+
+
+def _create_mxc_to_http_filter(public_baseurl: str) -> Callable:
+    """Create and return a jinja2 filter that converts MXC urls to HTTP
+
+    Args:
+        public_baseurl: The public, accessible base URL of the homeserver
+    """
+
+    def mxc_to_http_filter(value, width, height, resize_method="crop"):
+        if value[0:6] != "mxc://":
+            return ""
+
+        server_and_media_id = value[6:]
+        fragment = None
+        if "#" in server_and_media_id:
+            server_and_media_id, fragment = server_and_media_id.split("#", 1)
+            fragment = "#" + fragment
+
+        params = {"width": width, "height": height, "method": resize_method}
+        return "%s_matrix/media/v1/thumbnail/%s?%s%s" % (
+            public_baseurl,
+            server_and_media_id,
+            urllib.parse.urlencode(params),
+            fragment or "",
+        )
+
+    return mxc_to_http_filter
+

 class RootConfig(object):
    """
--- a/synapse/config/_util.py
+++ b/synapse/config/_util.py
@@ -0,0 +1,49 @@
+# -*- 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 typing import Any, List
+
+import jsonschema
+
+from synapse.config._base import ConfigError
+from synapse.types import JsonDict
+
+
+def validate_config(json_schema: JsonDict, config: Any, config_path: List[str]) -> None:
+    """Validates a config setting against a JsonSchema definition
+
+    This can be used to validate a section of the config file against a schema
+    definition. If the validation fails, a ConfigError is raised with a textual
+    description of the problem.
+
+    Args:
+        json_schema: the schema to validate against
+        config: the configuration value to be validated
+        config_path: the path within the config file. This will be used as a basis
+           for the error message.
+    """
+    try:
+        jsonschema.validate(config, json_schema)
+    except jsonschema.ValidationError as e:
+        # copy `config_path` before modifying it.
+        path = list(config_path)
+        for p in list(e.path):
+            if isinstance(p, int):
+                path.append("<item %i>" % p)
+            else:
+                path.append(str(p))
+
+        raise ConfigError(
+            "Unable to parse configuration: %s at %s" % (e.message, ".".join(path))
+        )
--- a/synapse/config/database.py
+++ b/synapse/config/database.py
@@ -100,7 +100,10 @@ class DatabaseConnectionConfig:

        self.name = name
        self.config = db_config
-        self.data_stores = data_stores
+
+        # The `data_stores` config is actually talking about `databases` (we
+        # changed the name).
+        self.databases = data_stores


 class DatabaseConfig(Config):
--- a/synapse/config/emailconfig.py
+++ b/synapse/config/emailconfig.py
@@ -23,7 +23,6 @@ from enum import Enum
 from typing import Optional

 import attr
-import pkg_resources

 from ._base import Config, ConfigError

@@ -98,21 +97,18 @@ class EmailConfig(Config):
            if parsed[1] == "":
                raise RuntimeError("Invalid notif_from address")

+        # A user-configurable template directory
        template_dir = email_config.get("template_dir")
-        # we need an absolute path, because we change directory after starting (and
-        # we don't yet know what auxiliary templates like mail.css we will need).
-        # (Note that loading as package_resources with jinja.PackageLoader doesn't
-        # work for the same reason.)
-        if not template_dir:
-            template_dir = pkg_resources.resource_filename("synapse", "res/templates")
-
-        self.email_template_dir = os.path.abspath(template_dir)
+        if isinstance(template_dir, str):
+            # We need an absolute path, because we change directory after starting (and
+            # we don't yet know what auxiliary templates like mail.css we will need).
+            template_dir = os.path.abspath(template_dir)
+        elif template_dir is not None:
+            # If template_dir is something other than a str or None, warn the user
+            raise ConfigError("Config option email.template_dir must be type str")

        self.email_enable_notifs = email_config.get("enable_notifs", False)

-        account_validity_config = config.get("account_validity") or {}
-        account_validity_renewal_enabled = account_validity_config.get("renew_at")
-
        self.threepid_behaviour_email = (
            # Have Synapse handle the email sending if account_threepid_delegates.email
            # is not defined
@@ -166,19 +162,6 @@ class EmailConfig(Config):
            email_config.get("validation_token_lifetime", "1h")
        )

-        if (
-            self.email_enable_notifs
-            or account_validity_renewal_enabled
-            or self.threepid_behaviour_email == ThreepidBehaviour.LOCAL
-        ):
-            # make sure we can import the required deps
-            import bleach
-            import jinja2
-
-            # prevent unused warnings
-            jinja2
-            bleach
-
        if self.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
            missing = []
            if not self.email_notif_from:
@@ -196,49 +179,49 @@ class EmailConfig(Config):

            # These email templates have placeholders in them, and thus must be
            # parsed using a templating engine during a request
-            self.email_password_reset_template_html = email_config.get(
+            password_reset_template_html = email_config.get(
                "password_reset_template_html", "password_reset.html"
            )
-            self.email_password_reset_template_text = email_config.get(
+            password_reset_template_text = email_config.get(
                "password_reset_template_text", "password_reset.txt"
            )
-            self.email_registration_template_html = email_config.get(
+            registration_template_html = email_config.get(
                "registration_template_html", "registration.html"
            )
-            self.email_registration_template_text = email_config.get(
+            registration_template_text = email_config.get(
                "registration_template_text", "registration.txt"
            )
-            self.email_add_threepid_template_html = email_config.get(
+            add_threepid_template_html = email_config.get(
                "add_threepid_template_html", "add_threepid.html"
            )
-            self.email_add_threepid_template_text = email_config.get(
+            add_threepid_template_text = email_config.get(
                "add_threepid_template_text", "add_threepid.txt"
            )

-            self.email_password_reset_template_failure_html = email_config.get(
+            password_reset_template_failure_html = email_config.get(
                "password_reset_template_failure_html", "password_reset_failure.html"
            )
-            self.email_registration_template_failure_html = email_config.get(
+            registration_template_failure_html = email_config.get(
                "registration_template_failure_html", "registration_failure.html"
            )
-            self.email_add_threepid_template_failure_html = email_config.get(
+            add_threepid_template_failure_html = email_config.get(
                "add_threepid_template_failure_html", "add_threepid_failure.html"
            )

            # These templates do not support any placeholder variables, so we
            # will read them from disk once during setup
-            email_password_reset_template_success_html = email_config.get(
+            password_reset_template_success_html = email_config.get(
                "password_reset_template_success_html", "password_reset_success.html"
            )
-            email_registration_template_success_html = email_config.get(
+            registration_template_success_html = email_config.get(
                "registration_template_success_html", "registration_success.html"
            )
-            email_add_threepid_template_success_html = email_config.get(
+            add_threepid_template_success_html = email_config.get(
                "add_threepid_template_success_html", "add_threepid_success.html"
            )

-            # Check templates exist
-            for f in [
+            # Read all templates from disk
+            (
                self.email_password_reset_template_html,
                self.email_password_reset_template_text,
                self.email_registration_template_html,
@@ -248,32 +231,36 @@ class EmailConfig(Config):
                self.email_password_reset_template_failure_html,
                self.email_registration_template_failure_html,
                self.email_add_threepid_template_failure_html,
-                email_password_reset_template_success_html,
-                email_registration_template_success_html,
-                email_add_threepid_template_success_html,
-            ]:
-                p = os.path.join(self.email_template_dir, f)
-                if not os.path.isfile(p):
-                    raise ConfigError("Unable to find template file %s" % (p,))
+                password_reset_template_success_html_template,
+                registration_template_success_html_template,
+                add_threepid_template_success_html_template,
+            ) = self.read_templates(
+                [
+                    password_reset_template_html,
+                    password_reset_template_text,
+                    registration_template_html,
+                    registration_template_text,
+                    add_threepid_template_html,
+                    add_threepid_template_text,
+                    password_reset_template_failure_html,
+                    registration_template_failure_html,
+                    add_threepid_template_failure_html,
+                    password_reset_template_success_html,
+                    registration_template_success_html,
+                    add_threepid_template_success_html,
+                ],
+                template_dir,
+            )

-            # Retrieve content of web templates
-            filepath = os.path.join(
-                self.email_template_dir, email_password_reset_template_success_html
+            # Render templates that do not contain any placeholders
+            self.email_password_reset_template_success_html_content = (
+                password_reset_template_success_html_template.render()
            )
-            self.email_password_reset_template_success_html = self.read_file(
-                filepath, "email.password_reset_template_success_html"
+            self.email_registration_template_success_html_content = (
+                registration_template_success_html_template.render()
            )
-            filepath = os.path.join(
-                self.email_template_dir, email_registration_template_success_html
-            )
-            self.email_registration_template_success_html_content = self.read_file(
-                filepath, "email.registration_template_success_html"
-            )
-            filepath = os.path.join(
-                self.email_template_dir, email_add_threepid_template_success_html
-            )
-            self.email_add_threepid_template_success_html_content = self.read_file(
-                filepath, "email.add_threepid_template_success_html"
+            self.email_add_threepid_template_success_html_content = (
+                add_threepid_template_success_html_template.render()
            )

        if self.email_enable_notifs:
@@ -290,17 +277,19 @@ class EmailConfig(Config):
                    % (", ".join(missing),)
                )

-            self.email_notif_template_html = email_config.get(
+            notif_template_html = email_config.get(
                "notif_template_html", "notif_mail.html"
            )
-            self.email_notif_template_text = email_config.get(
+            notif_template_text = email_config.get(
                "notif_template_text", "notif_mail.txt"
            )

-            for f in self.email_notif_template_text, self.email_notif_template_html:
-                p = os.path.join(self.email_template_dir, f)
-                if not os.path.isfile(p):
-                    raise ConfigError("Unable to find email template file %s" % (p,))
+            (
+                self.email_notif_template_html,
+                self.email_notif_template_text,
+            ) = self.read_templates(
+                [notif_template_html, notif_template_text], template_dir,
+            )

            self.email_notif_for_new_users = email_config.get(
                "notif_for_new_users", True
@@ -309,18 +298,20 @@ class EmailConfig(Config):
                "client_base_url", email_config.get("riot_base_url", None)
            )

-        if account_validity_renewal_enabled:
-            self.email_expiry_template_html = email_config.get(
+        if self.account_validity.renew_by_email_enabled:
+            expiry_template_html = email_config.get(
                "expiry_template_html", "notice_expiry.html"
            )
-            self.email_expiry_template_text = email_config.get(
+            expiry_template_text = email_config.get(
                "expiry_template_text", "notice_expiry.txt"
            )

-            for f in self.email_expiry_template_text, self.email_expiry_template_html:
-                p = os.path.join(self.email_template_dir, f)
-                if not os.path.isfile(p):
-                    raise ConfigError("Unable to find email template file %s" % (p,))
+            (
+                self.account_validity_template_html,
+                self.account_validity_template_text,
+            ) = self.read_templates(
+                [expiry_template_html, expiry_template_text], template_dir,
+            )

        subjects_config = email_config.get("subjects", {})
        subjects = {}
@@ -400,9 +391,7 @@ class EmailConfig(Config):
          # Directory in which Synapse will try to find the template files below.
          # If not set, default templates from within the Synapse package will be used.
          #
-          # DO NOT UNCOMMENT THIS SETTING unless you want to customise the templates.
-          # If you *do* uncomment it, you will need to make sure that all the templates
-          # below are in the directory.
+          # Do not uncomment this setting unless you want to customise the templates.
          #
          # Synapse will look for the following templates in this directory:
          #
--- a/synapse/config/logger.py
+++ b/synapse/config/logger.py
@@ -55,24 +55,33 @@ formatters:
        format: '%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - \
 %(request)s - %(message)s'

-filters:
-    context:
-        (): synapse.logging.context.LoggingContextFilter
-        request: ""
-
 handlers:
    file:
-        class: logging.handlers.RotatingFileHandler
+        class: logging.handlers.TimedRotatingFileHandler
        formatter: precise
        filename: ${log_file}
-        maxBytes: 104857600
-        backupCount: 10
-        filters: [context]
+        when: midnight
+        backupCount: 3  # Does not include the current log file.
        encoding: utf8
+
+    # Default to buffering writes to log file for efficiency. This means that
+    # will be a delay for INFO/DEBUG logs to get written, but WARNING/ERROR
+    # logs will still be flushed immediately.
+    buffer:
+        class: logging.handlers.MemoryHandler
+        target: file
+        # The capacity is the number of log lines that are buffered before
+        # being written to disk. Increasing this will lead to better
+        # performance, at the expensive of it taking longer for log lines to
+        # be written to disk.
+        capacity: 10
+        flushLevel: 30  # Flush for WARNING logs as well
+
+    # A handler that writes logs to stderr. Unused by default, but can be used
+    # instead of "buffer" and "file" in the logger handlers.
    console:
        class: logging.StreamHandler
        formatter: precise
-        filters: [context]

 loggers:
    synapse.storage.SQL:
@@ -80,9 +89,24 @@ loggers:
        # information such as access tokens.
        level: INFO

+    twisted:
+        # We send the twisted logging directly to the file handler,
+        # to work around https://github.com/matrix-org/synapse/issues/3471
+        # when using "buffer" logger. Use "console" to log to stderr instead.
+        handlers: [file]
+        propagate: false
+
 root:
    level: INFO
-    handlers: [file, console]
+
+    # Write logs to the `buffer` handler, which will buffer them together in memory,
+    # 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
+    # this case.)
+    #
+    handlers: [buffer]

 disable_existing_loggers: false
 """
@@ -168,11 +192,26 @@ def _setup_stdlib_logging(config, log_config, logBeginner: LogBeginner):

        handler = logging.StreamHandler()
        handler.setFormatter(formatter)
-        handler.addFilter(LoggingContextFilter(request=""))
        logger.addHandler(handler)
    else:
        logging.config.dictConfig(log_config)

+    # We add a log record factory that runs all messages through the
+    # LoggingContextFilter so that we get the context *at the time we log*
+    # rather than when we write to a handler. This can be done in config using
+    # filter options, but care must when using e.g. MemoryHandler to buffer
+    # writes.
+
+    log_filter = LoggingContextFilter(request="")
+    old_factory = logging.getLogRecordFactory()
+
+    def factory(*args, **kwargs):
+        record = old_factory(*args, **kwargs)
+        log_filter.filter(record)
+        return record
+
+    logging.setLogRecordFactory(factory)
+
    # Route Twisted's native logging through to the standard library logging
    # system.
    observer = STDLibLogObserver()
--- a/synapse/config/ratelimiting.py
+++ b/synapse/config/ratelimiting.py
@@ -93,6 +93,15 @@ class RatelimitConfig(Config):
        if rc_admin_redaction:
            self.rc_admin_redaction = RateLimitConfig(rc_admin_redaction)

+        self.rc_joins_local = RateLimitConfig(
+            config.get("rc_joins", {}).get("local", {}),
+            defaults={"per_second": 0.1, "burst_count": 3},
+        )
+        self.rc_joins_remote = RateLimitConfig(
+            config.get("rc_joins", {}).get("remote", {}),
+            defaults={"per_second": 0.01, "burst_count": 3},
+        )
+
    def generate_config_section(self, **kwargs):
        return """\
        ## Ratelimiting ##
@@ -118,6 +127,10 @@ class RatelimitConfig(Config):
        #   - one for ratelimiting redactions by room admins. If this is not explicitly
        #     set then it uses the same ratelimiting as per rc_message. This is useful
        #     to allow room admins to deal with abuse quickly.
+        #   - two for ratelimiting number of rooms a user can join, "local" for when
+        #     users are joining rooms the server is already in (this is cheap) vs
+        #     "remote" for when users are trying to join rooms not on the server (which
+        #     can be more expensive)
        #
        # The defaults are as shown below.
        #
@@ -143,6 +156,14 @@ class RatelimitConfig(Config):
        #rc_admin_redaction:
        #  per_second: 1
        #  burst_count: 50
+        #
+        #rc_joins:
+        #  local:
+        #    per_second: 0.1
+        #    burst_count: 3
+        #  remote:
+        #    per_second: 0.01
+        #    burst_count: 3


        # Ratelimiting settings for incoming federation
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -333,24 +333,6 @@ class RegistrationConfig(Config):
        #
        #default_identity_server: https://matrix.org

-        # The list of identity servers trusted to verify third party
-        # identifiers by this server.
-        #
-        # Also defines the ID server which will be called when an account is
-        # deactivated (one will be picked arbitrarily).
-        #
-        # Note: This option is deprecated. Since v0.99.4, Synapse has tracked which identity
-        # server a 3PID has been bound to. For 3PIDs bound before then, Synapse runs a
-        # background migration script, informing itself that the identity server all of its
-        # 3PIDs have been bound to is likely one of the below.
-        #
-        # As of Synapse v1.4.0, all other functionality of this option has been deprecated, and
-        # it is now solely used for the purposes of the background migration script, and can be
-        # removed once it has run.
-        #trusted_third_party_id_servers:
-        #  - matrix.org
-        #  - vector.im
-
        # Handle threepid (email/phone etc) registration and password resets through a set of
        # *trusted* identity servers. Note that this allows the configured identity server to
        # reset passwords for accounts!
--- a/synapse/config/saml2_config.py
+++ b/synapse/config/saml2_config.py
@@ -15,14 +15,15 @@
 # limitations under the License.

 import logging
+from typing import Any, List

-import jinja2
-import pkg_resources
+import attr

 from synapse.python_dependencies import DependencyException, check_requirements
 from synapse.util.module_loader import load_module, load_python_module

 from ._base import Config, ConfigError
+from ._util import validate_config

 logger = logging.getLogger(__name__)

@@ -80,6 +81,11 @@ class SAML2Config(Config):

        self.saml2_enabled = True

+        attribute_requirements = saml2_config.get("attribute_requirements") or []
+        self.attribute_requirements = _parse_attribute_requirements_def(
+            attribute_requirements
+        )
+
        self.saml2_grandfathered_mxid_source_attribute = saml2_config.get(
            "grandfathered_mxid_source_attribute", "uid"
        )
@@ -163,15 +169,9 @@ class SAML2Config(Config):
            saml2_config.get("saml_session_lifetime", "15m")
        )

-        template_dir = saml2_config.get("template_dir")
-        if not template_dir:
-            template_dir = pkg_resources.resource_filename("synapse", "res/templates",)
-
-        loader = jinja2.FileSystemLoader(template_dir)
-        # enable auto-escape here, to having to remember to escape manually in the
-        # template
-        env = jinja2.Environment(loader=loader, autoescape=True)
-        self.saml2_error_html_template = env.get_template("saml_error.html")
+        self.saml2_error_html_template = self.read_templates(
+            ["saml_error.html"], saml2_config.get("template_dir")
+        )

    def _default_saml_config_dict(
        self, required_attributes: set, optional_attributes: set
@@ -341,6 +341,17 @@ class SAML2Config(Config):
          #
          #grandfathered_mxid_source_attribute: upn

+          # It is possible to configure Synapse to only allow logins if SAML attributes
+          # match particular values. The requirements can be listed under
+          # `attribute_requirements` as shown below. All of the listed attributes must
+          # match for the login to be permitted.
+          #
+          #attribute_requirements:
+          #  - attribute: userGroup
+          #    value: "staff"
+          #  - attribute: department
+          #    value: "sales"
+
          # Directory in which Synapse will try to find the template files below.
          # If not set, default templates from within the Synapse package will be used.
          #
@@ -368,3 +379,34 @@ class SAML2Config(Config):
        """ % {
            "config_dir_path": config_dir_path
        }
+
+
+@attr.s(frozen=True)
+class SamlAttributeRequirement:
+    """Object describing a single requirement for SAML attributes."""
+
+    attribute = attr.ib(type=str)
+    value = attr.ib(type=str)
+
+    JSON_SCHEMA = {
+        "type": "object",
+        "properties": {"attribute": {"type": "string"}, "value": {"type": "string"}},
+        "required": ["attribute", "value"],
+    }
+
+
+ATTRIBUTE_REQUIREMENTS_SCHEMA = {
+    "type": "array",
+    "items": SamlAttributeRequirement.JSON_SCHEMA,
+}
+
+
+def _parse_attribute_requirements_def(
+    attribute_requirements: Any,
+) -> List[SamlAttributeRequirement]:
+    validate_config(
+        ATTRIBUTE_REQUIREMENTS_SCHEMA,
+        attribute_requirements,
+        config_path=["saml2_config", "attribute_requirements"],
+    )
+    return [SamlAttributeRequirement(**x) for x in attribute_requirements]
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -26,7 +26,6 @@ import yaml

 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.http.endpoint import parse_and_validate_server_name
-from synapse.python_dependencies import DependencyException, check_requirements

 from ._base import Config, ConfigError

@@ -439,6 +438,9 @@ class ServerConfig(Config):
                validator=attr.validators.instance_of(str),
                default=ROOM_COMPLEXITY_TOO_GREAT,
            )
+            admins_can_join = attr.ib(
+                validator=attr.validators.instance_of(bool), default=False
+            )

        self.limit_remote_rooms = LimitRemoteRoomsConfig(
            **(config.get("limit_remote_rooms") or {})
@@ -505,8 +507,6 @@ class ServerConfig(Config):
                )
            )

-        _check_resource_config(self.listeners)
-
        self.cleanup_extremities_with_dummy_events = config.get(
            "cleanup_extremities_with_dummy_events", True
        )
@@ -527,6 +527,21 @@ class ServerConfig(Config):
            "request_token_inhibit_3pid_errors", False,
        )

+        # List of users trialing the new experimental default push rules. This setting is
+        # not included in the sample configuration file on purpose as it's a temporary
+        # hack, so that some users can trial the new defaults without impacting every
+        # user on the homeserver.
+        users_new_default_push_rules = (
+            config.get("users_new_default_push_rules") or []
+        )  # type: list
+        if not isinstance(users_new_default_push_rules, list):
+            raise ConfigError("'users_new_default_push_rules' must be a list")
+
+        # Turn the list into a set to improve lookup speed.
+        self.users_new_default_push_rules = set(
+            users_new_default_push_rules
+        )  # type: set
+
    def has_tls_listener(self) -> bool:
        return any(listener.tls for listener in self.listeners)

@@ -893,6 +908,10 @@ class ServerConfig(Config):
          #
          #complexity_error: "This room is too complex."

+          # allow server admins to join complex rooms. Default is false.
+          #
+          #admins_can_join: true
+
        # Whether to require a user to be in the room to add an alias to it.
        # Defaults to 'true'.
        #
@@ -1111,20 +1130,3 @@ def _warn_if_webclient_configured(listeners: Iterable[ListenerConfig]) -> None:
                if name == "webclient":
                    logger.warning(NO_MORE_WEB_CLIENT_WARNING)
                    return
-
-
-def _check_resource_config(listeners: Iterable[ListenerConfig]) -> None:
-    resource_names = {
-        res_name
-        for listener in listeners
-        if listener.http_options
-        for res in listener.http_options.resources
-        for res_name in res.names
-    }
-
-    for resource in resource_names:
-        if resource == "consent":
-            try:
-                check_requirements("resources.consent")
-            except DependencyException as e:
-                raise ConfigError(e.message)
--- a/synapse/config/sso.py
+++ b/synapse/config/sso.py
@@ -12,11 +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 os
 from typing import Any, Dict

-import pkg_resources
-
 from ._base import Config


@@ -29,22 +26,32 @@ class SSOConfig(Config):
    def read_config(self, config, **kwargs):
        sso_config = config.get("sso") or {}  # type: Dict[str, Any]

-        # Pick a template directory in order of:
-        # * The sso-specific template_dir
-        # * /path/to/synapse/install/res/templates
+        # The sso-specific template_dir
        template_dir = sso_config.get("template_dir")
-        if not template_dir:
-            template_dir = pkg_resources.resource_filename("synapse", "res/templates",)

-        self.sso_template_dir = template_dir
-        self.sso_account_deactivated_template = self.read_file(
-            os.path.join(self.sso_template_dir, "sso_account_deactivated.html"),
-            "sso_account_deactivated_template",
+        # Read templates from disk
+        (
+            self.sso_redirect_confirm_template,
+            self.sso_auth_confirm_template,
+            self.sso_error_template,
+            sso_account_deactivated_template,
+            sso_auth_success_template,
+        ) = self.read_templates(
+            [
+                "sso_redirect_confirm.html",
+                "sso_auth_confirm.html",
+                "sso_error.html",
+                "sso_account_deactivated.html",
+                "sso_auth_success.html",
+            ],
+            template_dir,
        )
-        self.sso_auth_success_template = self.read_file(
-            os.path.join(self.sso_template_dir, "sso_auth_success.html"),
-            "sso_auth_success_template",
+
+        # These templates have no placeholders, so render them here
+        self.sso_account_deactivated_template = (
+            sso_account_deactivated_template.render()
        )
+        self.sso_auth_success_template = sso_auth_success_template.render()

        self.sso_client_whitelist = sso_config.get("client_whitelist") or []

--- a/synapse/crypto/context_factory.py
+++ b/synapse/crypto/context_factory.py
@@ -48,6 +48,14 @@ class ServerContextFactory(ContextFactory):
    connections."""

    def __init__(self, config):
+        # TODO: once pyOpenSSL exposes TLS_METHOD and SSL_CTX_set_min_proto_version,
+        # switch to those (see https://github.com/pyca/cryptography/issues/5379).
+        #
+        # note that, despite the confusing name, SSLv23_METHOD does *not* enforce SSLv2
+        # or v3, but is a synonym for TLS_METHOD, which allows the client and server
+        # to negotiate an appropriate version of TLS constrained by the version options
+        # set with context.set_options.
+        #
        self._context = SSL.Context(SSL.SSLv23_METHOD)
        self.configure_context(self._context, config)

--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -223,8 +223,7 @@ class Keyring(object):

        return results

-    @defer.inlineCallbacks
-    def _start_key_lookups(self, verify_requests):
+    async def _start_key_lookups(self, verify_requests):
        """Sets off the key fetches for each verify request

        Once each fetch completes, verify_request.key_ready will be resolved.
@@ -245,7 +244,7 @@ class Keyring(object):
                server_to_request_ids.setdefault(server_name, set()).add(request_id)

            # Wait for any previous lookups to complete before proceeding.
-            yield self.wait_for_previous_lookups(server_to_request_ids.keys())
+            await self.wait_for_previous_lookups(server_to_request_ids.keys())

            # take out a lock on each of the servers by sticking a Deferred in
            # key_downloads
@@ -283,15 +282,14 @@ class Keyring(object):
        except Exception:
            logger.exception("Error starting key lookups")

-    @defer.inlineCallbacks
-    def wait_for_previous_lookups(self, server_names):
+    async def wait_for_previous_lookups(self, server_names) -> None:
        """Waits for any previous key lookups for the given servers to finish.

        Args:
            server_names (Iterable[str]): list of servers which we want to look up

        Returns:
-            Deferred[None]: resolves once all key lookups for the given servers have
+            Resolves once all key lookups for the given servers have
                completed. Follows the synapse rules of logcontext preservation.
        """
        loop_count = 1
@@ -309,7 +307,7 @@ class Keyring(object):
                loop_count,
            )
            with PreserveLoggingContext():
-                yield defer.DeferredList((w[1] for w in wait_on))
+                await defer.DeferredList((w[1] for w in wait_on))

            loop_count += 1

@@ -326,44 +324,44 @@ class Keyring(object):

        remaining_requests = {rq for rq in verify_requests if not rq.key_ready.called}

-        @defer.inlineCallbacks
-        def do_iterations():
-            with Measure(self.clock, "get_server_verify_keys"):
-                for f in self._key_fetchers:
-                    if not remaining_requests:
-                        return
-                    yield self._attempt_key_fetches_with_fetcher(f, remaining_requests)
-
-                # look for any requests which weren't satisfied
-                with PreserveLoggingContext():
-                    for verify_request in remaining_requests:
-                        verify_request.key_ready.errback(
-                            SynapseError(
-                                401,
-                                "No key for %s with ids in %s (min_validity %i)"
-                                % (
-                                    verify_request.server_name,
-                                    verify_request.key_ids,
-                                    verify_request.minimum_valid_until_ts,
-                                ),
-                                Codes.UNAUTHORIZED,
-                            )
+        async def do_iterations():
+            try:
+                with Measure(self.clock, "get_server_verify_keys"):
+                    for f in self._key_fetchers:
+                        if not remaining_requests:
+                            return
+                        await self._attempt_key_fetches_with_fetcher(
+                            f, remaining_requests
                        )

-        def on_err(err):
-            # we don't really expect to get here, because any errors should already
-            # have been caught and logged. But if we do, let's log the error and make
-            # sure that all of the deferreds are resolved.
-            logger.error("Unexpected error in _get_server_verify_keys: %s", err)
-            with PreserveLoggingContext():
-                for verify_request in remaining_requests:
-                    if not verify_request.key_ready.called:
-                        verify_request.key_ready.errback(err)
+                    # look for any requests which weren't satisfied
+                    with PreserveLoggingContext():
+                        for verify_request in remaining_requests:
+                            verify_request.key_ready.errback(
+                                SynapseError(
+                                    401,
+                                    "No key for %s with ids in %s (min_validity %i)"
+                                    % (
+                                        verify_request.server_name,
+                                        verify_request.key_ids,
+                                        verify_request.minimum_valid_until_ts,
+                                    ),
+                                    Codes.UNAUTHORIZED,
+                                )
+                            )
+            except Exception as err:
+                # we don't really expect to get here, because any errors should already
+                # have been caught and logged. But if we do, let's log the error and make
+                # sure that all of the deferreds are resolved.
+                logger.error("Unexpected error in _get_server_verify_keys: %s", err)
+                with PreserveLoggingContext():
+                    for verify_request in remaining_requests:
+                        if not verify_request.key_ready.called:
+                            verify_request.key_ready.errback(err)

-        run_in_background(do_iterations).addErrback(on_err)
+        run_in_background(do_iterations)

-    @defer.inlineCallbacks
-    def _attempt_key_fetches_with_fetcher(self, fetcher, remaining_requests):
+    async def _attempt_key_fetches_with_fetcher(self, fetcher, remaining_requests):
        """Use a key fetcher to attempt to satisfy some key requests

        Args:
@@ -390,7 +388,7 @@ class Keyring(object):
                    verify_request.minimum_valid_until_ts,
                )

-        results = yield fetcher.get_keys(missing_keys)
+        results = await fetcher.get_keys(missing_keys)

        completed = []
        for verify_request in remaining_requests:
@@ -423,7 +421,7 @@ class Keyring(object):


 class KeyFetcher(object):
-    def get_keys(self, keys_to_fetch):
+    async def get_keys(self, keys_to_fetch):
        """
        Args:
            keys_to_fetch (dict[str, dict[str, int]]):
@@ -442,8 +440,7 @@ class StoreKeyFetcher(KeyFetcher):
    def __init__(self, hs):
        self.store = hs.get_datastore()

-    @defer.inlineCallbacks
-    def get_keys(self, keys_to_fetch):
+    async def get_keys(self, keys_to_fetch):
        """see KeyFetcher.get_keys"""

        keys_to_fetch = (
@@ -452,7 +449,7 @@ class StoreKeyFetcher(KeyFetcher):
            for key_id in keys_for_server.keys()
        )

-        res = yield self.store.get_server_verify_keys(keys_to_fetch)
+        res = await self.store.get_server_verify_keys(keys_to_fetch)
        keys = {}
        for (server_name, key_id), key in res.items():
            keys.setdefault(server_name, {})[key_id] = key
@@ -464,8 +461,7 @@ class BaseV2KeyFetcher(object):
        self.store = hs.get_datastore()
        self.config = hs.get_config()

-    @defer.inlineCallbacks
-    def process_v2_response(self, from_server, response_json, time_added_ms):
+    async def process_v2_response(self, from_server, response_json, time_added_ms):
        """Parse a 'Server Keys' structure from the result of a /key request

        This is used to parse either the entirety of the response from
@@ -537,7 +533,7 @@ class BaseV2KeyFetcher(object):

        key_json_bytes = encode_canonical_json(response_json)

-        yield make_deferred_yieldable(
+        await make_deferred_yieldable(
            defer.gatherResults(
                [
                    run_in_background(
@@ -567,14 +563,12 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher):
        self.client = hs.get_http_client()
        self.key_servers = self.config.key_servers

-    @defer.inlineCallbacks
-    def get_keys(self, keys_to_fetch):
+    async def get_keys(self, keys_to_fetch):
        """see KeyFetcher.get_keys"""

-        @defer.inlineCallbacks
-        def get_key(key_server):
+        async def get_key(key_server):
            try:
-                result = yield self.get_server_verify_key_v2_indirect(
+                result = await self.get_server_verify_key_v2_indirect(
                    keys_to_fetch, key_server
                )
                return result
@@ -592,7 +586,7 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher):

            return {}

-        results = yield make_deferred_yieldable(
+        results = await make_deferred_yieldable(
            defer.gatherResults(
                [run_in_background(get_key, server) for server in self.key_servers],
                consumeErrors=True,
@@ -606,8 +600,7 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher):

        return union_of_keys

-    @defer.inlineCallbacks
-    def get_server_verify_key_v2_indirect(self, keys_to_fetch, key_server):
+    async def get_server_verify_key_v2_indirect(self, keys_to_fetch, key_server):
        """
        Args:
            keys_to_fetch (dict[str, dict[str, int]]):
@@ -617,7 +610,7 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher):
                the keys

        Returns:
-            Deferred[dict[str, dict[str, synapse.storage.keys.FetchKeyResult]]]: map
+            dict[str, dict[str, synapse.storage.keys.FetchKeyResult]]: map
                from server_name -> key_id -> FetchKeyResult

        Raises:
@@ -632,7 +625,7 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher):
        )

        try:
-            query_response = yield self.client.post_json(
+            query_response = await self.client.post_json(
                destination=perspective_name,
                path="/_matrix/key/v2/query",
                data={
@@ -668,7 +661,7 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher):
            try:
                self._validate_perspectives_response(key_server, response)

-                processed_response = yield self.process_v2_response(
+                processed_response = await self.process_v2_response(
                    perspective_name, response, time_added_ms=time_now_ms
                )
            except KeyLookupError as e:
@@ -687,7 +680,7 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher):
            )
            keys.setdefault(server_name, {}).update(processed_response)

-        yield self.store.store_server_verify_keys(
+        await self.store.store_server_verify_keys(
            perspective_name, time_now_ms, added_keys
        )

@@ -739,24 +732,23 @@ class ServerKeyFetcher(BaseV2KeyFetcher):
        self.clock = hs.get_clock()
        self.client = hs.get_http_client()

-    def get_keys(self, keys_to_fetch):
+    async def get_keys(self, keys_to_fetch):
        """
        Args:
            keys_to_fetch (dict[str, iterable[str]]):
                the keys to be fetched. server_name -> key_ids

        Returns:
-            Deferred[dict[str, dict[str, synapse.storage.keys.FetchKeyResult|None]]]:
+            dict[str, dict[str, synapse.storage.keys.FetchKeyResult|None]]:
                map from server_name -> key_id -> FetchKeyResult
        """

        results = {}

-        @defer.inlineCallbacks
-        def get_key(key_to_fetch_item):
+        async def get_key(key_to_fetch_item):
            server_name, key_ids = key_to_fetch_item
            try:
-                keys = yield self.get_server_verify_key_v2_direct(server_name, key_ids)
+                keys = await self.get_server_verify_key_v2_direct(server_name, key_ids)
                results[server_name] = keys
            except KeyLookupError as e:
                logger.warning(
@@ -765,12 +757,11 @@ class ServerKeyFetcher(BaseV2KeyFetcher):
            except Exception:
                logger.exception("Error getting keys %s from %s", key_ids, server_name)

-        return yieldable_gather_results(get_key, keys_to_fetch.items()).addCallback(
-            lambda _: results
-        )
+        return await yieldable_gather_results(
+            get_key, keys_to_fetch.items()
+        ).addCallback(lambda _: results)

-    @defer.inlineCallbacks
-    def get_server_verify_key_v2_direct(self, server_name, key_ids):
+    async def get_server_verify_key_v2_direct(self, server_name, key_ids):
        """

        Args:
@@ -792,7 +783,7 @@ class ServerKeyFetcher(BaseV2KeyFetcher):

            time_now_ms = self.clock.time_msec()
            try:
-                response = yield self.client.get_json(
+                response = await self.client.get_json(
                    destination=server_name,
                    path="/_matrix/key/v2/server/"
                    + urllib.parse.quote(requested_key_id),
@@ -823,12 +814,12 @@ class ServerKeyFetcher(BaseV2KeyFetcher):
                    % (server_name, response["server_name"])
                )

-            response_keys = yield self.process_v2_response(
+            response_keys = await self.process_v2_response(
                from_server=server_name,
                response_json=response,
                time_added_ms=time_now_ms,
            )
-            yield self.store.store_server_verify_keys(
+            await self.store.store_server_verify_keys(
                server_name,
                time_now_ms,
                ((server_name, key_id, key) for key_id, key in response_keys.items()),
@@ -838,22 +829,18 @@ class ServerKeyFetcher(BaseV2KeyFetcher):
        return keys


-@defer.inlineCallbacks
-def _handle_key_deferred(verify_request):
+async def _handle_key_deferred(verify_request) -> None:
    """Waits for the key to become available, and then performs a verification

    Args:
        verify_request (VerifyJsonRequest):

-    Returns:
-        Deferred[None]
-
    Raises:
        SynapseError if there was a problem performing the verification
    """
    server_name = verify_request.server_name
    with PreserveLoggingContext():
-        _, key_id, verify_key = yield verify_request.key_ready
+        _, key_id, verify_key = await verify_request.key_ready

    json_object = verify_request.json_object

--- a/synapse/events/builder.py
+++ b/synapse/events/builder.py
@@ -17,8 +17,7 @@ from typing import Optional
 import attr
 from nacl.signing import SigningKey

-from twisted.internet import defer
-
+from synapse.api.auth import Auth
 from synapse.api.constants import MAX_DEPTH
 from synapse.api.errors import UnsupportedRoomVersionError
 from synapse.api.room_versions import (
@@ -29,6 +28,8 @@ from synapse.api.room_versions import (
 )
 from synapse.crypto.event_signing import add_hashes_and_signatures
 from synapse.events import EventBase, _EventInternalMetadata, make_event_from_dict
+from synapse.state import StateHandler
+from synapse.storage.databases.main import DataStore
 from synapse.types import EventID, JsonDict
 from synapse.util import Clock
 from synapse.util.stringutils import random_string
@@ -44,45 +45,46 @@ class EventBuilder(object):

    Attributes:
        room_version: Version of the target room
-        room_id (str)
-        type (str)
-        sender (str)
-        content (dict)
-        unsigned (dict)
-        internal_metadata (_EventInternalMetadata)
+        room_id
+        type
+        sender
+        content
+        unsigned
+        internal_metadata

-        _state (StateHandler)
-        _auth (synapse.api.Auth)
-        _store (DataStore)
-        _clock (Clock)
-        _hostname (str): The hostname of the server creating the event
+        _state
+        _auth
+        _store
+        _clock
+        _hostname: The hostname of the server creating the event
        _signing_key: The signing key to use to sign the event as the server
    """

-    _state = attr.ib()
-    _auth = attr.ib()
-    _store = attr.ib()
-    _clock = attr.ib()
-    _hostname = attr.ib()
-    _signing_key = attr.ib()
+    _state = attr.ib(type=StateHandler)
+    _auth = attr.ib(type=Auth)
+    _store = attr.ib(type=DataStore)
+    _clock = attr.ib(type=Clock)
+    _hostname = attr.ib(type=str)
+    _signing_key = attr.ib(type=SigningKey)

    room_version = attr.ib(type=RoomVersion)

-    room_id = attr.ib()
-    type = attr.ib()
-    sender = attr.ib()
+    room_id = attr.ib(type=str)
+    type = attr.ib(type=str)
+    sender = attr.ib(type=str)

-    content = attr.ib(default=attr.Factory(dict))
-    unsigned = attr.ib(default=attr.Factory(dict))
+    content = attr.ib(default=attr.Factory(dict), type=JsonDict)
+    unsigned = attr.ib(default=attr.Factory(dict), type=JsonDict)

    # These only exist on a subset of events, so they raise AttributeError if
    # someone tries to get them when they don't exist.
-    _state_key = attr.ib(default=None)
-    _redacts = attr.ib(default=None)
-    _origin_server_ts = attr.ib(default=None)
+    _state_key = attr.ib(default=None, type=Optional[str])
+    _redacts = attr.ib(default=None, type=Optional[str])
+    _origin_server_ts = attr.ib(default=None, type=Optional[int])

    internal_metadata = attr.ib(
-        default=attr.Factory(lambda: _EventInternalMetadata({}))
+        default=attr.Factory(lambda: _EventInternalMetadata({})),
+        type=_EventInternalMetadata,
    )

    @property
@@ -95,31 +97,30 @@ class EventBuilder(object):
    def is_state(self):
        return self._state_key is not None

-    @defer.inlineCallbacks
-    def build(self, prev_event_ids):
+    async def build(self, prev_event_ids):
        """Transform into a fully signed and hashed event

        Args:
            prev_event_ids (list[str]): The event IDs to use as the prev events

        Returns:
-            Deferred[FrozenEvent]
+            FrozenEvent
        """

-        state_ids = yield defer.ensureDeferred(
-            self._state.get_current_state_ids(self.room_id, prev_event_ids)
+        state_ids = await self._state.get_current_state_ids(
+            self.room_id, prev_event_ids
        )
-        auth_ids = yield self._auth.compute_auth_events(self, state_ids)
+        auth_ids = self._auth.compute_auth_events(self, state_ids)

        format_version = self.room_version.event_format
        if format_version == EventFormatVersions.V1:
-            auth_events = yield self._store.add_event_hashes(auth_ids)
-            prev_events = yield self._store.add_event_hashes(prev_event_ids)
+            auth_events = await self._store.add_event_hashes(auth_ids)
+            prev_events = await self._store.add_event_hashes(prev_event_ids)
        else:
            auth_events = auth_ids
            prev_events = prev_event_ids

-        old_depth = yield self._store.get_max_depth_of(prev_event_ids)
+        old_depth = await self._store.get_max_depth_of(prev_event_ids)
        depth = old_depth + 1

        # we cap depth of generated events, to ensure that they are not
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -12,17 +12,19 @@
 # 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 Optional, Union
+from typing import TYPE_CHECKING, Optional, Union

 import attr
 from frozendict import frozendict

-from twisted.internet import defer
-
 from synapse.appservice import ApplicationService
+from synapse.events import EventBase
 from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.types import StateMap

+if TYPE_CHECKING:
+    from synapse.storage.databases.main import DataStore
+

@attr.s(slots=True)
 class EventContext:
@@ -129,8 +131,7 @@ class EventContext:
            delta_ids=delta_ids,
        )

-    @defer.inlineCallbacks
-    def serialize(self, event, store):
+    async def serialize(self, event: EventBase, store: "DataStore") -> dict:
        """Converts self to a type that can be serialized as JSON, and then
        deserialized by `deserialize`

@@ -146,7 +147,7 @@ class EventContext:
        # the prev_state_ids, so if we're a state event we include the event
        # id that we replaced in the state.
        if event.is_state():
-            prev_state_ids = yield self.get_prev_state_ids()
+            prev_state_ids = await self.get_prev_state_ids()
            prev_state_id = prev_state_ids.get((event.type, event.state_key))
        else:
            prev_state_id = None
@@ -214,8 +215,7 @@ class EventContext:

        return self._state_group

-    @defer.inlineCallbacks
-    def get_current_state_ids(self):
+    async def get_current_state_ids(self) -> Optional[StateMap[str]]:
        """
        Gets the room state map, including this event - ie, the state in ``state_group``

@@ -224,32 +224,31 @@ class EventContext:
        ``rejected`` is set.

        Returns:
-            Deferred[dict[(str, str), str]|None]: Returns None if state_group
-                is None, which happens when the associated event is an outlier.
+            Returns None if state_group is None, which happens when the associated
+            event is an outlier.

-                Maps a (type, state_key) to the event ID of the state event matching
-                this tuple.
+            Maps a (type, state_key) to the event ID of the state event matching
+            this tuple.
        """
        if self.rejected:
            raise RuntimeError("Attempt to access state_ids of rejected event")

-        yield self._ensure_fetched()
+        await self._ensure_fetched()
        return self._current_state_ids

-    @defer.inlineCallbacks
-    def get_prev_state_ids(self):
+    async def get_prev_state_ids(self):
        """
        Gets the room state map, excluding this event.

        For a non-state event, this will be the same as get_current_state_ids().

        Returns:
-            Deferred[dict[(str, str), str]|None]: Returns None if state_group
+            dict[(str, str), str]|None: Returns None if state_group
                is None, which happens when the associated event is an outlier.
                Maps a (type, state_key) to the event ID of the state event matching
                this tuple.
        """
-        yield self._ensure_fetched()
+        await self._ensure_fetched()
        return self._prev_state_ids

    def get_cached_current_state_ids(self):
@@ -269,8 +268,8 @@ class EventContext:

        return self._current_state_ids

-    def _ensure_fetched(self):
-        return defer.succeed(None)
+    async def _ensure_fetched(self):
+        return None


@attr.s(slots=True)
@@ -303,21 +302,20 @@ class _AsyncEventContextImpl(EventContext):
    _event_state_key = attr.ib(default=None)
    _fetching_state_deferred = attr.ib(default=None)

-    def _ensure_fetched(self):
+    async def _ensure_fetched(self):
        if not self._fetching_state_deferred:
            self._fetching_state_deferred = run_in_background(self._fill_out_state)

-        return make_deferred_yieldable(self._fetching_state_deferred)
+        return await make_deferred_yieldable(self._fetching_state_deferred)

-    @defer.inlineCallbacks
-    def _fill_out_state(self):
+    async def _fill_out_state(self):
        """Called to populate the _current_state_ids and _prev_state_ids
        attributes by loading from the database.
        """
        if self.state_group is None:
            return

-        self._current_state_ids = yield self._storage.state.get_state_ids_for_group(
+        self._current_state_ids = await self._storage.state.get_state_ids_for_group(
            self.state_group
        )
        if self._event_state_key is not None:
--- a/synapse/events/third_party_rules.py
+++ b/synapse/events/third_party_rules.py
@@ -13,7 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.

-from twisted.internet import defer
+from synapse.events import EventBase
+from synapse.events.snapshot import EventContext
+from synapse.types import Requester


 class ThirdPartyEventRules(object):
@@ -39,76 +41,79 @@ class ThirdPartyEventRules(object):
                config=config, http_client=hs.get_simple_http_client()
            )

-    @defer.inlineCallbacks
-    def check_event_allowed(self, event, context):
+    async def check_event_allowed(
+        self, event: EventBase, context: EventContext
+    ) -> bool:
        """Check if a provided event should be allowed in the given context.

        Args:
-            event (synapse.events.EventBase): The event to be checked.
-            context (synapse.events.snapshot.EventContext): The context of the event.
+            event: The event to be checked.
+            context: The context of the event.

        Returns:
-            defer.Deferred[bool]: True if the event should be allowed, False if not.
+            True if the event should be allowed, False if not.
        """
        if self.third_party_rules is None:
            return True

-        prev_state_ids = yield context.get_prev_state_ids()
+        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] = yield self.store.get_event(event_id, allow_none=True)
+            state_events[key] = await self.store.get_event(event_id, allow_none=True)

-        ret = yield self.third_party_rules.check_event_allowed(event, state_events)
+        ret = await self.third_party_rules.check_event_allowed(event, state_events)
        return ret

-    @defer.inlineCallbacks
-    def on_create_room(self, requester, config, is_requester_admin):
+    async def on_create_room(
+        self, requester: Requester, config: dict, is_requester_admin: bool
+    ) -> bool:
        """Intercept requests to create room to allow, deny or update the
        request config.

        Args:
-            requester (Requester)
-            config (dict): The creation config from the client.
-            is_requester_admin (bool): If the requester is an admin
+            requester
+            config: The creation config from the client.
+            is_requester_admin: If the requester is an admin

        Returns:
-            defer.Deferred[bool]: Whether room creation is allowed or denied.
+            Whether room creation is allowed or denied.
        """

        if self.third_party_rules is None:
            return True

-        ret = yield self.third_party_rules.on_create_room(
+        ret = await self.third_party_rules.on_create_room(
            requester, config, is_requester_admin
        )
        return ret

-    @defer.inlineCallbacks
-    def check_threepid_can_be_invited(self, medium, address, room_id):
+    async def check_threepid_can_be_invited(
+        self, medium: str, address: str, room_id: str
+    ) -> bool:
        """Check if a provided 3PID can be invited in the given room.

        Args:
-            medium (str): The 3PID's medium.
-            address (str): The 3PID's address.
-            room_id (str): The room we want to invite the threepid to.
+            medium: The 3PID's medium.
+            address: The 3PID's address.
+            room_id: The room we want to invite the threepid to.

        Returns:
-            defer.Deferred[bool], True if the 3PID can be invited, False if not.
+            True if the 3PID can be invited, False if not.
        """

        if self.third_party_rules is None:
            return True

-        state_ids = yield self.store.get_filtered_current_state_ids(room_id)
-        room_state_events = yield self.store.get_events(state_ids.values())
+        state_ids = await self.store.get_filtered_current_state_ids(room_id)
+        room_state_events = await self.store.get_events(state_ids.values())

        state_events = {}
        for key, event_id in state_ids.items():
            state_events[key] = room_state_events[event_id]

-        ret = yield self.third_party_rules.check_threepid_can_be_invited(
+        ret = await self.third_party_rules.check_threepid_can_be_invited(
            medium, address, state_events
        )
        return ret
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -18,8 +18,6 @@ from typing import Any, Mapping, Union

 from frozendict import frozendict

-from twisted.internet import defer
-
 from synapse.api.constants import EventTypes, RelationTypes
 from synapse.api.errors import Codes, SynapseError
 from synapse.api.room_versions import RoomVersion
@@ -337,8 +335,9 @@ class EventClientSerializer(object):
            hs.config.experimental_msc1849_support_enabled
        )

-    @defer.inlineCallbacks
-    def serialize_event(self, event, time_now, bundle_aggregations=True, **kwargs):
+    async def serialize_event(
+        self, event, time_now, bundle_aggregations=True, **kwargs
+    ):
        """Serializes a single event.

        Args:
@@ -348,7 +347,7 @@ class EventClientSerializer(object):
            **kwargs: Arguments to pass to `serialize_event`

        Returns:
-            Deferred[dict]: The serialized event
+            dict: The serialized event
        """
        # To handle the case of presence events and the like
        if not isinstance(event, EventBase):
@@ -363,8 +362,8 @@ class EventClientSerializer(object):
        if not event.internal_metadata.is_redacted() and (
            self.experimental_msc1849_support_enabled and bundle_aggregations
        ):
-            annotations = yield self.store.get_aggregation_groups_for_event(event_id)
-            references = yield self.store.get_relations_for_event(
+            annotations = await self.store.get_aggregation_groups_for_event(event_id)
+            references = await self.store.get_relations_for_event(
                event_id, RelationTypes.REFERENCE, direction="f"
            )

@@ -378,7 +377,7 @@ class EventClientSerializer(object):

            edit = None
            if event.type == EventTypes.Message:
-                edit = yield self.store.get_applicable_edit(event_id)
+                edit = await self.store.get_applicable_edit(event_id)

            if edit:
                # If there is an edit replace the content, preserving existing
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -135,7 +135,7 @@ class FederationClient(FederationBase):
                and try the request anyway.

        Returns:
-            a Deferred which will eventually yield a JSON object from the
+            a Awaitable which will eventually yield a JSON object from the
            response
        """
        sent_queries_counter.labels(query_type).inc()
@@ -157,7 +157,7 @@ class FederationClient(FederationBase):
            content (dict): The query content.

        Returns:
-            a Deferred which will eventually yield a JSON object from the
+            an Awaitable which will eventually yield a JSON object from the
            response
        """
        sent_queries_counter.labels("client_device_keys").inc()
@@ -180,7 +180,7 @@ class FederationClient(FederationBase):
            content (dict): The query content.

        Returns:
-            a Deferred which will eventually yield a JSON object from the
+            an Awaitable which will eventually yield a JSON object from the
            response
        """
        sent_queries_counter.labels("client_one_time_keys").inc()
@@ -900,7 +900,7 @@ class FederationClient(FederationBase):
                party instance

        Returns:
-            Deferred[Dict[str, Any]]: The response from the remote server, or None if
+            Awaitable[Dict[str, Any]]: The response from the remote server, or None if
            `remote_server` is the same as the local server_name

        Raises:
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -37,8 +37,8 @@ from sortedcontainers import SortedDict

 from twisted.internet import defer

+from synapse.api.presence import UserPresenceState
 from synapse.metrics import LaterGauge
-from synapse.storage.presence import UserPresenceState
 from synapse.util.metrics import Measure

 from .units import Edu
--- a/synapse/federation/sender/init.py
+++ b/synapse/federation/sender/init.py
@@ -22,6 +22,7 @@ from twisted.internet import defer

 import synapse
 import synapse.metrics
+from synapse.api.presence import UserPresenceState
 from synapse.events import EventBase
 from synapse.federation.sender.per_destination_queue import PerDestinationQueue
 from synapse.federation.sender.transaction_manager import TransactionManager
@@ -39,7 +40,6 @@ from synapse.metrics import (
    events_processed_counter,
 )
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.storage.presence import UserPresenceState
 from synapse.types import ReadReceipt
 from synapse.util.metrics import Measure, measure_func

@@ -288,8 +288,7 @@ class FederationSender(object):
        for destination in destinations:
            self._get_per_destination_queue(destination).send_pdu(pdu, order)

-    @defer.inlineCallbacks
-    def send_read_receipt(self, receipt: ReadReceipt):
+    async def send_read_receipt(self, receipt: ReadReceipt) -> None:
        """Send a RR to any other servers in the room

        Args:
@@ -330,9 +329,7 @@ class FederationSender(object):
        room_id = receipt.room_id

        # Work out which remote servers should be poked and poke them.
-        domains = yield defer.ensureDeferred(
-            self.state.get_current_hosts_in_room(room_id)
-        )
+        domains = await self.state.get_current_hosts_in_room(room_id)
        domains = [
            d
            for d in domains
@@ -387,8 +384,7 @@ class FederationSender(object):
            queue.flush_read_receipts_for_room(room_id)

    @preserve_fn  # the caller should not yield on this
-    @defer.inlineCallbacks
-    def send_presence(self, states: List[UserPresenceState]):
+    async def send_presence(self, states: List[UserPresenceState]):
        """Send the new presence states to the appropriate destinations.

        This actually queues up the presence states ready for sending and
@@ -423,7 +419,7 @@ class FederationSender(object):
                if not states_map:
                    break

-                yield self._process_presence_inner(list(states_map.values()))
+                await self._process_presence_inner(list(states_map.values()))
        except Exception:
            logger.exception("Error sending presence states to servers")
        finally:
@@ -450,14 +446,11 @@ class FederationSender(object):
            self._get_per_destination_queue(destination).send_presence(states)

    @measure_func("txnqueue._process_presence")
-    @defer.inlineCallbacks
-    def _process_presence_inner(self, states: List[UserPresenceState]):
+    async def _process_presence_inner(self, states: List[UserPresenceState]):
        """Given a list of states populate self.pending_presence_by_dest and
        poke to send a new transaction to each destination
        """
-        hosts_and_states = yield defer.ensureDeferred(
-            get_interested_remotes(self.store, states, self.state)
-        )
+        hosts_and_states = await get_interested_remotes(self.store, states, self.state)

        for destinations, states in hosts_and_states:
            for destination in destinations:
--- a/synapse/federation/sender/per_destination_queue.py
+++ b/synapse/federation/sender/per_destination_queue.py
@@ -24,12 +24,12 @@ from synapse.api.errors import (
    HttpResponseException,
    RequestSendFailed,
 )
+from synapse.api.presence import UserPresenceState
 from synapse.events import EventBase
 from synapse.federation.units import Edu
 from synapse.handlers.presence import format_user_presence_state
 from synapse.metrics import sent_transactions_counter
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.storage.presence import UserPresenceState
 from synapse.types import ReadReceipt
 from synapse.util.retryutils import NotRetryingDestination, get_retry_limiter

@@ -337,6 +337,28 @@ class PerDestinationQueue(object):
                    (e.retry_last_ts + e.retry_interval) / 1000.0
                ),
            )
+
+            if e.retry_interval > 60 * 60 * 1000:
+                # we won't retry for another hour!
+                # (this suggests a significant outage)
+                # We drop pending PDUs and EDUs because otherwise they will
+                # rack up indefinitely.
+                # Note that:
+                # - the EDUs that are being dropped here are those that we can
+                #   afford to drop (specifically, only typing notifications,
+                #   read receipts and presence updates are being dropped here)
+                # - Other EDUs such as to_device messages are queued with a
+                #   different mechanism
+                # - this is all volatile state that would be lost if the
+                #   federation sender restarted anyway
+
+                # dropping read receipts is a bit sad but should be solved
+                # through another mechanism, because this is all volatile!
+                self._pending_pdus = []
+                self._pending_edus = []
+                self._pending_edus_keyed = {}
+                self._pending_presence = {}
+                self._pending_rrs = {}
        except FederationDeniedError as e:
            logger.info(e)
        except HttpResponseException as e:
--- a/synapse/federation/sender/transaction_manager.py
+++ b/synapse/federation/sender/transaction_manager.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import TYPE_CHECKING, List
+from typing import TYPE_CHECKING, List, Tuple

 from canonicaljson import json

@@ -54,7 +54,10 @@ class TransactionManager(object):

    @measure_func("_send_new_transaction")
    async def send_new_transaction(
-        self, destination: str, pending_pdus: List[EventBase], pending_edus: List[Edu]
+        self,
+        destination: str,
+        pending_pdus: List[Tuple[EventBase, int]],
+        pending_edus: List[Edu],
    ):

        # Make a transaction-sending opentracing span. This span follows on from
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -18,8 +18,6 @@ import logging
 import urllib
 from typing import Any, Dict, Optional

-from twisted.internet import defer
-
 from synapse.api.constants import Membership
 from synapse.api.errors import Codes, HttpResponseException, SynapseError
 from synapse.api.urls import (
@@ -51,7 +49,7 @@ class TransportLayerClient(object):
            event_id (str): The event we want the context at.

        Returns:
-            Deferred: Results in a dict received from the remote homeserver.
+            Awaitable: Results in a dict received from the remote homeserver.
        """
        logger.debug("get_room_state_ids dest=%s, room=%s", destination, room_id)

@@ -75,7 +73,7 @@ class TransportLayerClient(object):
                giving up. None indicates no timeout.

        Returns:
-            Deferred: Results in a dict received from the remote homeserver.
+            Awaitable: Results in a dict received from the remote homeserver.
        """
        logger.debug("get_pdu dest=%s, event_id=%s", destination, event_id)

@@ -96,7 +94,7 @@ class TransportLayerClient(object):
            limit (int)

        Returns:
-            Deferred: Results in a dict received from the remote homeserver.
+            Awaitable: Results in a dict received from the remote homeserver.
        """
        logger.debug(
            "backfill dest=%s, room_id=%s, event_tuples=%r, limit=%s",
@@ -118,16 +116,15 @@ class TransportLayerClient(object):
            destination, path=path, args=args, try_trailing_slash_on_400=True
        )

-    @defer.inlineCallbacks
    @log_function
-    def send_transaction(self, transaction, json_data_callback=None):
+    async def send_transaction(self, transaction, json_data_callback=None):
        """ Sends the given Transaction to its destination

        Args:
            transaction (Transaction)

        Returns:
-            Deferred: Succeeds when we get a 2xx HTTP response. The result
+            Succeeds when we get a 2xx HTTP response. The result
            will be the decoded JSON body.

            Fails with ``HTTPRequestException`` if we get an HTTP response
@@ -154,7 +151,7 @@ class TransportLayerClient(object):

        path = _create_v1_path("/send/%s", transaction.transaction_id)

-        response = yield self.client.put_json(
+        response = await self.client.put_json(
            transaction.destination,
            path=path,
            data=json_data,
@@ -166,14 +163,13 @@ class TransportLayerClient(object):

        return response

-    @defer.inlineCallbacks
    @log_function
-    def make_query(
+    async def make_query(
        self, destination, query_type, args, retry_on_dns_fail, ignore_backoff=False
    ):
        path = _create_v1_path("/query/%s", query_type)

-        content = yield self.client.get_json(
+        content = await self.client.get_json(
            destination=destination,
            path=path,
            args=args,
@@ -184,9 +180,10 @@ class TransportLayerClient(object):

        return content

-    @defer.inlineCallbacks
    @log_function
-    def make_membership_event(self, destination, room_id, user_id, membership, params):
+    async def make_membership_event(
+        self, destination, room_id, user_id, membership, params
+    ):
        """Asks a remote server to build and sign us a membership event

        Note that this does not append any events to any graphs.
@@ -200,7 +197,7 @@ class TransportLayerClient(object):
                request.

        Returns:
-            Deferred: Succeeds when we get a 2xx HTTP response. The result
+            Succeeds when we get a 2xx HTTP response. The result
            will be the decoded JSON body (ie, the new event).

            Fails with ``HTTPRequestException`` if we get an HTTP response
@@ -231,7 +228,7 @@ class TransportLayerClient(object):
            ignore_backoff = True
            retry_on_dns_fail = True

-        content = yield self.client.get_json(
+        content = await self.client.get_json(
            destination=destination,
            path=path,
            args=params,
@@ -242,34 +239,31 @@ class TransportLayerClient(object):

        return content

-    @defer.inlineCallbacks
    @log_function
-    def send_join_v1(self, destination, room_id, event_id, content):
+    async def send_join_v1(self, destination, room_id, event_id, content):
        path = _create_v1_path("/send_join/%s/%s", room_id, event_id)

-        response = yield self.client.put_json(
+        response = await self.client.put_json(
            destination=destination, path=path, data=content
        )

        return response

-    @defer.inlineCallbacks
    @log_function
-    def send_join_v2(self, destination, room_id, event_id, content):
+    async def send_join_v2(self, destination, room_id, event_id, content):
        path = _create_v2_path("/send_join/%s/%s", room_id, event_id)

-        response = yield self.client.put_json(
+        response = await self.client.put_json(
            destination=destination, path=path, data=content
        )

        return response

-    @defer.inlineCallbacks
    @log_function
-    def send_leave_v1(self, destination, room_id, event_id, content):
+    async def send_leave_v1(self, destination, room_id, event_id, content):
        path = _create_v1_path("/send_leave/%s/%s", room_id, event_id)

-        response = yield self.client.put_json(
+        response = await self.client.put_json(
            destination=destination,
            path=path,
            data=content,
@@ -282,12 +276,11 @@ class TransportLayerClient(object):

        return response

-    @defer.inlineCallbacks
    @log_function
-    def send_leave_v2(self, destination, room_id, event_id, content):
+    async def send_leave_v2(self, destination, room_id, event_id, content):
        path = _create_v2_path("/send_leave/%s/%s", room_id, event_id)

-        response = yield self.client.put_json(
+        response = await self.client.put_json(
            destination=destination,
            path=path,
            data=content,
@@ -300,31 +293,28 @@ class TransportLayerClient(object):

        return response

-    @defer.inlineCallbacks
    @log_function
-    def send_invite_v1(self, destination, room_id, event_id, content):
+    async def send_invite_v1(self, destination, room_id, event_id, content):
        path = _create_v1_path("/invite/%s/%s", room_id, event_id)

-        response = yield self.client.put_json(
+        response = await self.client.put_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

        return response

-    @defer.inlineCallbacks
    @log_function
-    def send_invite_v2(self, destination, room_id, event_id, content):
+    async def send_invite_v2(self, destination, room_id, event_id, content):
        path = _create_v2_path("/invite/%s/%s", room_id, event_id)

-        response = yield self.client.put_json(
+        response = await self.client.put_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

        return response

-    @defer.inlineCallbacks
    @log_function
-    def get_public_rooms(
+    async def get_public_rooms(
        self,
        remote_server: str,
        limit: Optional[int] = None,
@@ -355,7 +345,7 @@ class TransportLayerClient(object):
            data["filter"] = search_filter

            try:
-                response = yield self.client.post_json(
+                response = await self.client.post_json(
                    destination=remote_server, path=path, data=data, ignore_backoff=True
                )
            except HttpResponseException as e:
@@ -381,7 +371,7 @@ class TransportLayerClient(object):
                args["since"] = [since_token]

            try:
-                response = yield self.client.get_json(
+                response = await self.client.get_json(
                    destination=remote_server, path=path, args=args, ignore_backoff=True
                )
            except HttpResponseException as e:
@@ -396,29 +386,26 @@ class TransportLayerClient(object):

        return response

-    @defer.inlineCallbacks
    @log_function
-    def exchange_third_party_invite(self, destination, room_id, event_dict):
+    async def exchange_third_party_invite(self, destination, room_id, event_dict):
        path = _create_v1_path("/exchange_third_party_invite/%s", room_id)

-        response = yield self.client.put_json(
+        response = await self.client.put_json(
            destination=destination, path=path, data=event_dict
        )

        return response

-    @defer.inlineCallbacks
    @log_function
-    def get_event_auth(self, destination, room_id, event_id):
+    async def get_event_auth(self, destination, room_id, event_id):
        path = _create_v1_path("/event_auth/%s/%s", room_id, event_id)

-        content = yield self.client.get_json(destination=destination, path=path)
+        content = await self.client.get_json(destination=destination, path=path)

        return content

-    @defer.inlineCallbacks
    @log_function
-    def query_client_keys(self, destination, query_content, timeout):
+    async def query_client_keys(self, destination, query_content, timeout):
        """Query the device keys for a list of user ids hosted on a remote
        server.

@@ -453,14 +440,13 @@ class TransportLayerClient(object):
        """
        path = _create_v1_path("/user/keys/query")

-        content = yield self.client.post_json(
+        content = await self.client.post_json(
            destination=destination, path=path, data=query_content, timeout=timeout
        )
        return content

-    @defer.inlineCallbacks
    @log_function
-    def query_user_devices(self, destination, user_id, timeout):
+    async def query_user_devices(self, destination, user_id, timeout):
        """Query the devices for a user id hosted on a remote server.

        Response:
@@ -493,14 +479,13 @@ class TransportLayerClient(object):
        """
        path = _create_v1_path("/user/devices/%s", user_id)

-        content = yield self.client.get_json(
+        content = await self.client.get_json(
            destination=destination, path=path, timeout=timeout
        )
        return content

-    @defer.inlineCallbacks
    @log_function
-    def claim_client_keys(self, destination, query_content, timeout):
+    async def claim_client_keys(self, destination, query_content, timeout):
        """Claim one-time keys for a list of devices hosted on a remote server.

        Request:
@@ -532,14 +517,13 @@ class TransportLayerClient(object):

        path = _create_v1_path("/user/keys/claim")

-        content = yield self.client.post_json(
+        content = await self.client.post_json(
            destination=destination, path=path, data=query_content, timeout=timeout
        )
        return content

-    @defer.inlineCallbacks
    @log_function
-    def get_missing_events(
+    async def get_missing_events(
        self,
        destination,
        room_id,
@@ -551,7 +535,7 @@ class TransportLayerClient(object):
    ):
        path = _create_v1_path("/get_missing_events/%s", room_id)

-        content = yield self.client.post_json(
+        content = await self.client.post_json(
            destination=destination,
            path=path,
            data={
--- a/synapse/groups/attestations.py
+++ b/synapse/groups/attestations.py
@@ -41,8 +41,6 @@ from typing import Tuple

 from signedjson.sign import sign_json

-from twisted.internet import defer
-
 from synapse.api.errors import HttpResponseException, RequestSendFailed, SynapseError
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.types import get_domain_from_id
@@ -72,8 +70,9 @@ class GroupAttestationSigning(object):
        self.server_name = hs.hostname
        self.signing_key = hs.signing_key

-    @defer.inlineCallbacks
-    def verify_attestation(self, attestation, group_id, user_id, server_name=None):
+    async def verify_attestation(
+        self, attestation, group_id, user_id, server_name=None
+    ):
        """Verifies that the given attestation matches the given parameters.

        An optional server_name can be supplied to explicitly set which server's
@@ -102,7 +101,7 @@ class GroupAttestationSigning(object):
        if valid_until_ms < now:
            raise SynapseError(400, "Attestation expired")

-        yield self.keyring.verify_json_for_server(
+        await self.keyring.verify_json_for_server(
            server_name, attestation, now, "Group attestation"
        )

@@ -142,8 +141,7 @@ class GroupAttestionRenewer(object):
                self._start_renew_attestations, 30 * 60 * 1000
            )

-    @defer.inlineCallbacks
-    def on_renew_attestation(self, group_id, user_id, content):
+    async def on_renew_attestation(self, group_id, user_id, content):
        """When a remote updates an attestation
        """
        attestation = content["attestation"]
@@ -151,11 +149,11 @@ class GroupAttestionRenewer(object):
        if not self.is_mine_id(group_id) and not self.is_mine_id(user_id):
            raise SynapseError(400, "Neither user not group are on this server")

-        yield self.attestations.verify_attestation(
+        await self.attestations.verify_attestation(
            attestation, user_id=user_id, group_id=group_id
        )

-        yield self.store.update_remote_attestion(group_id, user_id, attestation)
+        await self.store.update_remote_attestion(group_id, user_id, attestation)

        return {}

@@ -172,8 +170,7 @@ class GroupAttestionRenewer(object):
            now + UPDATE_ATTESTATION_TIME_MS
        )

-        @defer.inlineCallbacks
-        def _renew_attestation(group_user: Tuple[str, str]):
+        async def _renew_attestation(group_user: Tuple[str, str]):
            group_id, user_id = group_user
            try:
                if not self.is_mine_id(group_id):
@@ -186,16 +183,16 @@ class GroupAttestionRenewer(object):
                        user_id,
                        group_id,
                    )
-                    yield self.store.remove_attestation_renewal(group_id, user_id)
+                    await self.store.remove_attestation_renewal(group_id, user_id)
                    return

                attestation = self.attestations.create_attestation(group_id, user_id)

-                yield self.transport_client.renew_group_attestation(
+                await self.transport_client.renew_group_attestation(
                    destination, group_id, user_id, content={"attestation": attestation}
                )

-                yield self.store.update_attestation_renewal(
+                await self.store.update_attestation_renewal(
                    group_id, user_id, attestation
                )
            except (RequestSendFailed, HttpResponseException) as e:
--- a/synapse/groups/groups_server.py
+++ b/synapse/groups/groups_server.py
@@ -719,6 +719,27 @@ class GroupsServerHandler(GroupsServerWorkerHandler):

        raise NotImplementedError()

+    async def change_user_admin_in_group(
+        self, group_id, user_id, want_admin, requester_user_id, content
+    ):
+        """Promotes or demotes a user in a group.
+        """
+
+        await self.check_group_is_ours(group_id, requester_user_id, and_exists=True)
+
+        if requester_user_id == user_id:
+            raise SynapseError(400, "User cannot target themselves")
+
+        is_admin = await self.store.is_user_admin_in_group(
+            group_id, requester_user_id
+        )
+        if not is_admin:
+            raise SynapseError(403, "User is not admin in group")
+
+        await self.store.change_user_admin_in_group(group_id, user_id, want_admin)
+
+        return {}
+
    async def remove_user_from_group(
        self, group_id, user_id, requester_user_id, content
    ):
--- a/synapse/handlers/account_validity.py
+++ b/synapse/handlers/account_validity.py
@@ -26,11 +26,6 @@ from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.types import UserID
 from synapse.util import stringutils

-try:
-    from synapse.push.mailer import load_jinja2_templates
-except ImportError:
-    load_jinja2_templates = None
-
 logger = logging.getLogger(__name__)


@@ -47,9 +42,11 @@ class AccountValidityHandler(object):
        if (
            self._account_validity.enabled
            and self._account_validity.renew_by_email_enabled
-            and load_jinja2_templates
        ):
            # Don't do email-specific configuration if renewal by email is disabled.
+            self._template_html = self.config.account_validity_template_html
+            self._template_text = self.config.account_validity_template_text
+
            try:
                app_name = self.hs.config.email_app_name

@@ -65,17 +62,6 @@ class AccountValidityHandler(object):

            self._raw_from = email.utils.parseaddr(self._from_string)[1]

-            self._template_html, self._template_text = load_jinja2_templates(
-                self.config.email_template_dir,
-                [
-                    self.config.email_expiry_template_html,
-                    self.config.email_expiry_template_text,
-                ],
-                apply_format_ts_filter=True,
-                apply_mxc_to_http_filter=True,
-                public_baseurl=self.config.public_baseurl,
-            )
-
            # 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
--- a/synapse/handlers/acme.py
+++ b/synapse/handlers/acme.py
@@ -17,7 +17,6 @@ import logging

 import twisted
 import twisted.internet.error
-from twisted.internet import defer
 from twisted.web import server, static
 from twisted.web.resource import Resource

@@ -41,8 +40,7 @@ class AcmeHandler(object):
        self.reactor = hs.get_reactor()
        self._acme_domain = hs.config.acme_domain

-    @defer.inlineCallbacks
-    def start_listening(self):
+    async def start_listening(self):
        from synapse.handlers import acme_issuing_service

        # Configure logging for txacme, if you need to debug
@@ -82,18 +80,17 @@ class AcmeHandler(object):
        self._issuer._registered = False

        try:
-            yield self._issuer._ensure_registered()
+            await self._issuer._ensure_registered()
        except Exception:
            logger.error(ACME_REGISTER_FAIL_ERROR)
            raise

-    @defer.inlineCallbacks
-    def provision_certificate(self):
+    async def provision_certificate(self):

        logger.warning("Reprovisioning %s", self._acme_domain)

        try:
-            yield self._issuer.issue_cert(self._acme_domain)
+            await self._issuer.issue_cert(self._acme_domain)
        except Exception:
            logger.exception("Fail!")
            raise
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -27,7 +27,6 @@ from synapse.metrics import (
    event_processing_loop_room_count,
 )
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.util import log_failure
 from synapse.util.metrics import Measure

 logger = logging.getLogger(__name__)
@@ -100,10 +99,11 @@ class ApplicationServicesHandler(object):

                        if not self.started_scheduler:

-                            def start_scheduler():
-                                return self.scheduler.start().addErrback(
-                                    log_failure, "Application Services Failure"
-                                )
+                            async def start_scheduler():
+                                try:
+                                    return await self.scheduler.start()
+                                except Exception:
+                                    logger.error("Application Services Failure")

                            run_as_background_process("as_scheduler", start_scheduler)
                            self.started_scheduler = True
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -42,7 +42,6 @@ from synapse.http.site import SynapseRequest
 from synapse.logging.context import defer_to_thread
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.module_api import ModuleApi
-from synapse.push.mailer import load_jinja2_templates
 from synapse.types import Requester, UserID
 from synapse.util import stringutils as stringutils
 from synapse.util.threepids import canonicalise_email
@@ -132,18 +131,17 @@ class AuthHandler(BaseHandler):
        # after the SSO completes and before redirecting them back to their client.
        # It notifies the user they are about to give access to their matrix account
        # to the client.
-        self._sso_redirect_confirm_template = load_jinja2_templates(
-            hs.config.sso_template_dir, ["sso_redirect_confirm.html"],
-        )[0]
+        self._sso_redirect_confirm_template = hs.config.sso_redirect_confirm_template
+
        # The following template is shown during user interactive authentication
        # in the fallback auth scenario. It notifies the user that they are
        # authenticating for an operation to occur on their account.
-        self._sso_auth_confirm_template = load_jinja2_templates(
-            hs.config.sso_template_dir, ["sso_auth_confirm.html"],
-        )[0]
+        self._sso_auth_confirm_template = hs.config.sso_auth_confirm_template
+
        # The following template is shown after a successful user interactive
        # authentication session. It tells the user they can close the window.
        self._sso_auth_success_template = hs.config.sso_auth_success_template
+
        # The following template is shown during the SSO authentication process if
        # the account is deactivated.
        self._sso_account_deactivated_template = (
@@ -162,7 +160,7 @@ class AuthHandler(BaseHandler):
        request_body: Dict[str, Any],
        clientip: str,
        description: str,
-    ) -> dict:
+    ) -> Tuple[dict, str]:
        """
        Checks that the user is who they claim to be, via a UI auth.

@@ -183,9 +181,14 @@ class AuthHandler(BaseHandler):
                         describes the operation happening on their account.

        Returns:
-            The parameters for this request (which may
+            A tuple of (params, session_id).
+
+                'params' contains the parameters for this request (which may
                have been given only in a previous call).

+                'session_id' is the ID of this session, either passed in by the
+                client or assigned by this call
+
        Raises:
            InteractiveAuthIncompleteError if the client has not yet completed
                any of the permitted login flows
@@ -207,7 +210,7 @@ class AuthHandler(BaseHandler):
        flows = [[login_type] for login_type in self._supported_ui_auth_types]

        try:
-            result, params, _ = await self.check_auth(
+            result, params, session_id = await self.check_ui_auth(
                flows, request, request_body, clientip, description
            )
        except LoginError:
@@ -230,7 +233,7 @@ class AuthHandler(BaseHandler):
        if user_id != requester.user.to_string():
            raise AuthError(403, "Invalid auth")

-        return params
+        return params, session_id

    def get_enabled_auth_types(self):
        """Return the enabled user-interactive authentication types
@@ -240,7 +243,7 @@ class AuthHandler(BaseHandler):
        """
        return self.checkers.keys()

-    async def check_auth(
+    async def check_ui_auth(
        self,
        flows: List[List[str]],
        request: SynapseRequest,
@@ -363,7 +366,7 @@ class AuthHandler(BaseHandler):

        if not authdict:
            raise InteractiveAuthIncompleteError(
-                self._auth_dict_for_flows(flows, session.session_id)
+                session.session_id, self._auth_dict_for_flows(flows, session.session_id)
            )

        # check auth type currently being presented
@@ -410,7 +413,7 @@ class AuthHandler(BaseHandler):
        ret = self._auth_dict_for_flows(flows, session.session_id)
        ret["completed"] = list(creds)
        ret.update(errordict)
-        raise InteractiveAuthIncompleteError(ret)
+        raise InteractiveAuthIncompleteError(session.session_id, ret)

    async def add_oob_auth(
        self, stagetype: str, authdict: Dict[str, Any], clientip: str
--- a/synapse/handlers/events.py
+++ b/synapse/handlers/events.py
@@ -57,13 +57,10 @@ class EventStreamHandler(BaseHandler):
        timeout=0,
        as_client_event=True,
        affect_presence=True,
-        only_keys=None,
        room_id=None,
        is_guest=False,
    ):
        """Fetches the events stream for a given user.
-
-        If `only_keys` is not None, events from keys will be sent down.
        """

        if room_id:
@@ -93,7 +90,6 @@ class EventStreamHandler(BaseHandler):
                auth_user,
                pagin_config,
                timeout,
-                only_keys=only_keys,
                is_guest=is_guest,
                explicit_room_id=room_id,
            )
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -71,7 +71,7 @@ from synapse.replication.http.federation import (
 )
 from synapse.replication.http.membership import ReplicationUserJoinedLeftRoomRestServlet
 from synapse.state import StateResolutionStore, resolve_events_with_store
-from synapse.storage.data_stores.main.events_worker import EventRedactBehaviour
+from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.types import JsonDict, StateMap, UserID, get_domain_from_id
 from synapse.util.async_helpers import Linearizer, concurrently_execute
 from synapse.util.distributor import user_joined_room
@@ -2064,7 +2064,7 @@ class FederationHandler(BaseHandler):

        if not auth_events:
            prev_state_ids = await context.get_prev_state_ids()
-            auth_events_ids = await self.auth.compute_auth_events(
+            auth_events_ids = self.auth.compute_auth_events(
                event, prev_state_ids, for_verification=True
            )
            auth_events_x = await self.store.get_events(auth_events_ids)
@@ -2470,7 +2470,7 @@ class FederationHandler(BaseHandler):
        }

        current_state_ids = await context.get_current_state_ids()
-        current_state_ids = dict(current_state_ids)
+        current_state_ids = dict(current_state_ids)  # type: ignore

        current_state_ids.update(state_updates)

--- a/synapse/handlers/groups_local.py
+++ b/synapse/handlers/groups_local.py
@@ -23,39 +23,32 @@ logger = logging.getLogger(__name__)


 def _create_rerouter(func_name):
-    """Returns a function that looks at the group id and calls the function
+    """Returns an async function that looks at the group id and calls the function
    on federation or the local group server if the group is local
    """

-    def f(self, group_id, *args, **kwargs):
+    async def f(self, group_id, *args, **kwargs):
        if self.is_mine_id(group_id):
-            return getattr(self.groups_server_handler, func_name)(
+            return await getattr(self.groups_server_handler, func_name)(
                group_id, *args, **kwargs
            )
        else:
            destination = get_domain_from_id(group_id)
-            d = getattr(self.transport_client, func_name)(
-                destination, group_id, *args, **kwargs
-            )

-            # Capture errors returned by the remote homeserver and
-            # re-throw specific errors as SynapseErrors. This is so
-            # when the remote end responds with things like 403 Not
-            # In Group, we can communicate that to the client instead
-            # of a 500.
-            def http_response_errback(failure):
-                failure.trap(HttpResponseException)
-                e = failure.value
+            try:
+                return await getattr(self.transport_client, func_name)(
+                    destination, group_id, *args, **kwargs
+                )
+            except HttpResponseException as e:
+                # Capture errors returned by the remote homeserver and
+                # re-throw specific errors as SynapseErrors. This is so
+                # when the remote end responds with things like 403 Not
+                # In Group, we can communicate that to the client instead
+                # of a 500.
                raise e.to_synapse_error()
-
-            def request_failed_errback(failure):
-                failure.trap(RequestSendFailed)
+            except RequestSendFailed:
                raise SynapseError(502, "Failed to contact group server")

-            d.addErrback(http_response_errback)
-            d.addErrback(request_failed_errback)
-            return d
-
    return f


@@ -468,6 +461,25 @@ class GroupsLocalHandler(GroupsLocalWorkerHandler):

        return {"state": "invite", "user_profile": user_profile}

+    async def change_user_admin_in_group(
+        self, group_id, user_id, want_admin, requester_user_id, content
+    ):
+        """Promotes or demotes a user in a group.
+        """
+
+        if not self.is_mine_id(user_id):
+            raise SynapseError(400, "User not on this server")
+
+        # TODO: We should probably support federation, but this is fine for now
+        if not self.is_mine_id(group_id):
+            raise SynapseError(400, "Group not on this server")
+
+        res = await self.groups_server_handler.change_user_admin_in_group(
+            group_id, user_id, want_admin, requester_user_id, content
+        )
+
+        return res
+
    async def remove_user_from_group(
        self, group_id, user_id, requester_user_id, content
    ):
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -22,14 +22,10 @@ import urllib.parse
 from typing import Awaitable, Callable, Dict, List, Optional, Tuple

 from canonicaljson import json
-from signedjson.key import decode_verify_key_bytes
-from signedjson.sign import verify_signed_json
-from unpaddedbase64 import decode_base64

 from twisted.internet.error import TimeoutError

 from synapse.api.errors import (
-    AuthError,
    CodeMessageException,
    Codes,
    HttpResponseException,
@@ -628,9 +624,9 @@ class IdentityHandler(BaseHandler):
            )

            if "mxid" in data:
-                if "signatures" not in data:
-                    raise AuthError(401, "No signatures on 3pid binding")
-                await self._verify_any_signature(data, id_server)
+                # note: we used to verify the identity server's signature here, but no longer
+                # require or validate it. See the following for context:
+                # https://github.com/matrix-org/synapse/issues/5253#issuecomment-666246950
                return data["mxid"]
        except TimeoutError:
            raise SynapseError(500, "Timed out contacting identity server")
@@ -751,30 +747,6 @@ class IdentityHandler(BaseHandler):
        mxid = lookup_results["mappings"].get(lookup_value)
        return mxid

-    async def _verify_any_signature(self, data, server_hostname):
-        if server_hostname not in data["signatures"]:
-            raise AuthError(401, "No signature from server %s" % (server_hostname,))
-        for key_name, signature in data["signatures"][server_hostname].items():
-            try:
-                key_data = await self.blacklisting_http_client.get_json(
-                    "%s%s/_matrix/identity/api/v1/pubkey/%s"
-                    % (id_server_scheme, server_hostname, key_name)
-                )
-            except TimeoutError:
-                raise SynapseError(500, "Timed out contacting identity server")
-            if "public_key" not in key_data:
-                raise AuthError(
-                    401, "No public key named %s from %s" % (key_name, server_hostname)
-                )
-            verify_signed_json(
-                data,
-                server_hostname,
-                decode_verify_key_bytes(
-                    key_name, decode_base64(key_data["public_key"])
-                ),
-            )
-            return
-
    async def ask_id_server_for_third_party_invite(
        self,
        requester: Requester,
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -109,7 +109,7 @@ class InitialSyncHandler(BaseHandler):

        rooms_ret = []

-        now_token = await self.hs.get_event_sources().get_current_token()
+        now_token = self.hs.get_event_sources().get_current_token()

        presence_stream = self.hs.get_event_sources().sources["presence"]
        pagination_config = PaginationConfig(from_token=now_token)
@@ -360,7 +360,7 @@ class InitialSyncHandler(BaseHandler):
            current_state.values(), time_now
        )

-        now_token = await self.hs.get_event_sources().get_current_token()
+        now_token = self.hs.get_event_sources().get_current_token()

        limit = pagin_config.limit if pagin_config else None
        if limit is None:
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -15,7 +15,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import TYPE_CHECKING, List, Optional, Tuple
+from typing import TYPE_CHECKING, Dict, List, Optional, Tuple

 from canonicaljson import encode_canonical_json, json

@@ -45,7 +45,7 @@ from synapse.events.validator import EventValidator
 from synapse.logging.context import run_in_background
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.replication.http.send_event import ReplicationSendEventRestServlet
-from synapse.storage.data_stores.main.events_worker import EventRedactBehaviour
+from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.storage.state import StateFilter
 from synapse.types import (
    Collection,
@@ -93,11 +93,11 @@ class MessageHandler(object):

    async def get_room_data(
        self,
-        user_id: str = None,
-        room_id: str = None,
-        event_type: Optional[str] = None,
-        state_key: str = "",
-        is_guest: bool = False,
+        user_id: str,
+        room_id: str,
+        event_type: str,
+        state_key: str,
+        is_guest: bool,
    ) -> dict:
        """ Get data from a room.

@@ -407,7 +407,7 @@ class EventCreationHandler(object):
        #
        # map from room id to time-of-last-attempt.
        #
-        self._rooms_to_exclude_from_dummy_event_insertion = {}  # type: dict[str, int]
+        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
@@ -667,14 +667,14 @@ class EventCreationHandler(object):
        assert self.hs.is_mine(user), "User must be our own: %s" % (user,)

        if event.is_state():
-            prev_state = await self.deduplicate_state_event(event, context)
-            if prev_state is not None:
+            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_state.event_id,
+                    prev_event.event_id,
                )
-                return prev_state
+                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
@@ -682,32 +682,37 @@ class EventCreationHandler(object):

    async def deduplicate_state_event(
        self, event: EventBase, context: EventContext
-    ) -> None:
+    ) -> Optional[EventBase]:
        """
        Checks whether event is in the latest resolved state in context.

-        If so, returns the version of the event in context.
-        Otherwise, returns None.
+        Args:
+            event: The event to check for duplication.
+            context: The event context.
+
+        Returns:
+            The previous verion 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()
        prev_event_id = prev_state_ids.get((event.type, event.state_key))
        if not prev_event_id:
-            return
+            return None
        prev_event = await self.store.get_event(prev_event_id, allow_none=True)
        if not prev_event:
-            return
+            return None

        if prev_event and event.user_id == prev_event.user_id:
            prev_content = encode_canonical_json(prev_event.content)
            next_content = encode_canonical_json(event.content)
            if prev_content == next_content:
                return prev_event
-        return
+        return None

    async def create_and_send_nonmember_event(
        self,
        requester: Requester,
-        event_dict: EventBase,
+        event_dict: dict,
        ratelimit: bool = True,
        txn_id: Optional[str] = None,
    ) -> Tuple[EventBase, int]:
@@ -768,6 +773,15 @@ class EventCreationHandler(object):
        else:
            prev_event_ids = await self.store.get_prev_events_for_room(builder.room_id)

+        # we now ought to have some prev_events (unless it's a create event).
+        #
+        # do a quick sanity check here, rather than waiting until we've created the
+        # event and then try to auth it (which fails with a somewhat confusing "No
+        # create event in auth events")
+        assert (
+            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)
        context = await self.state.compute_event_context(event)
        if requester:
@@ -882,9 +896,7 @@ class EventCreationHandler(object):
        except Exception:
            # Ensure that we actually remove the entries in the push actions
            # staging area, if we calculated them.
-            run_in_background(
-                self.store.remove_push_actions_from_staging, event.event_id
-            )
+            await self.store.remove_push_actions_from_staging(event.event_id)
            raise

    async def _validate_canonical_alias(
@@ -962,7 +974,7 @@ class EventCreationHandler(object):
            # Validate a newly added alias or newly added alt_aliases.

            original_alias = None
-            original_alt_aliases = set()
+            original_alt_aliases = []  # type: List[str]

            original_event_id = event.unsigned.get("replaces_state")
            if original_event_id:
@@ -1010,6 +1022,10 @@ class EventCreationHandler(object):

                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()
@@ -1061,7 +1077,7 @@ class EventCreationHandler(object):
                    raise SynapseError(400, "Cannot redact event from a different room")

            prev_state_ids = await context.get_prev_state_ids()
-            auth_events_ids = await self.auth.compute_auth_events(
+            auth_events_ids = self.auth.compute_auth_events(
                event, prev_state_ids, for_verification=True
            )
            auth_events = await self.store.get_events(auth_events_ids)
--- a/synapse/handlers/oidc_handler.py
+++ b/synapse/handlers/oidc_handler.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 import json
 import logging
-from typing import Dict, Generic, List, Optional, Tuple, TypeVar
+from typing import TYPE_CHECKING, Dict, Generic, List, Optional, Tuple, TypeVar
 from urllib.parse import urlencode

 import attr
@@ -38,10 +38,11 @@ from synapse.config import ConfigError
 from synapse.http.server import respond_with_html
 from synapse.http.site import SynapseRequest
 from synapse.logging.context import make_deferred_yieldable
-from synapse.push.mailer import load_jinja2_templates
-from synapse.server import HomeServer
 from synapse.types import UserID, map_username_to_mxid_localpart

+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
 logger = logging.getLogger(__name__)

 SESSION_COOKIE_NAME = b"oidc_session"
@@ -91,7 +92,7 @@ class OidcHandler:
    """Handles requests related to the OpenID Connect login flow.
    """

-    def __init__(self, hs: HomeServer):
+    def __init__(self, hs: "HomeServer"):
        self._callback_url = hs.config.oidc_callback_url  # type: str
        self._scopes = hs.config.oidc_scopes  # type: List[str]
        self._client_auth = ClientAuth(
@@ -121,9 +122,7 @@ class OidcHandler:
        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 = load_jinja2_templates(
-            hs.config.sso_template_dir, ["sso_error.html"]
-        )[0]
+        self._error_template = hs.config.sso_error_template

        # identifier for the external_ids table
        self._auth_provider_id = "oidc"
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -309,7 +309,7 @@ class PaginationHandler(object):
            room_token = pagin_config.from_token.room_key
        else:
            pagin_config.from_token = (
-                await self.hs.get_event_sources().get_current_token_for_pagination()
+                self.hs.get_event_sources().get_current_token_for_pagination()
            )
            room_token = pagin_config.from_token.room_key

--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -33,13 +33,13 @@ from typing_extensions import ContextManager
 import synapse.metrics
 from synapse.api.constants import EventTypes, Membership, PresenceState
 from synapse.api.errors import SynapseError
+from synapse.api.presence import UserPresenceState
 from synapse.logging.context import run_in_background
 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.state import StateHandler
-from synapse.storage.data_stores.main import DataStore
-from synapse.storage.presence import UserPresenceState
+from synapse.storage.databases.main import DataStore
 from synapse.types import JsonDict, UserID, get_domain_from_id
 from synapse.util.async_helpers import Linearizer
 from synapse.util.caches.descriptors import cached
@@ -319,7 +319,7 @@ class PresenceHandler(BasePresenceHandler):
        is some spurious presence changes that will self-correct.
        """
        # If the DB pool has already terminated, don't try updating
-        if not self.store.db.is_running():
+        if not self.store.db_pool.is_running():
            return

        logger.info(
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -142,6 +142,7 @@ class RegistrationHandler(BaseHandler):
        address=None,
        bind_emails=[],
        by_admin=False,
+        shadow_banned=False,
    ):
        """Registers a new client on the server.

@@ -159,6 +160,7 @@ class RegistrationHandler(BaseHandler):
            bind_emails (List[str]): list of emails to bind to this account.
            by_admin (bool): True if this registration is being made via the
              admin api, otherwise False.
+            shadow_banned (bool): Shadow-ban the created user.
        Returns:
            str: user_id
        Raises:
@@ -194,6 +196,7 @@ class RegistrationHandler(BaseHandler):
                admin=admin,
                user_type=user_type,
                address=address,
+                shadow_banned=shadow_banned,
            )

            if self.hs.config.user_directory_search_all_users:
@@ -224,6 +227,7 @@ class RegistrationHandler(BaseHandler):
                        make_guest=make_guest,
                        create_profile_with_displayname=default_display_name,
                        address=address,
+                        shadow_banned=shadow_banned,
                    )

                    # Successfully registered
@@ -529,6 +533,7 @@ class RegistrationHandler(BaseHandler):
        admin=False,
        user_type=None,
        address=None,
+        shadow_banned=False,
    ):
        """Register user in the datastore.

@@ -546,9 +551,10 @@ class RegistrationHandler(BaseHandler):
            user_type (str|None): 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:
-            Deferred
+            Awaitable
        """
        if self.hs.config.worker_app:
            return self._register_client(
@@ -561,6 +567,7 @@ class RegistrationHandler(BaseHandler):
                admin=admin,
                user_type=user_type,
                address=address,
+                shadow_banned=shadow_banned,
            )
        else:
            return self.store.register_user(
@@ -572,6 +579,7 @@ class RegistrationHandler(BaseHandler):
                create_profile_with_displayname=create_profile_with_displayname,
                admin=admin,
                user_type=user_type,
+                shadow_banned=shadow_banned,
            )

    async def register_device(
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -22,7 +22,7 @@ import logging
 import math
 import string
 from collections import OrderedDict
-from typing import Optional, Tuple
+from typing import TYPE_CHECKING, Any, Awaitable, Dict, List, Optional, Tuple

 from synapse.api.constants import (
    EventTypes,
@@ -32,11 +32,14 @@ from synapse.api.constants import (
    RoomEncryptionAlgorithms,
 )
 from synapse.api.errors import AuthError, Codes, NotFoundError, StoreError, SynapseError
+from synapse.api.filtering import Filter
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion
+from synapse.events import EventBase
 from synapse.events.utils import copy_power_levels_contents
 from synapse.http.endpoint import parse_and_validate_server_name
 from synapse.storage.state import StateFilter
 from synapse.types import (
+    JsonDict,
    Requester,
    RoomAlias,
    RoomID,
@@ -53,6 +56,9 @@ from synapse.visibility import filter_events_for_client

 from ._base import BaseHandler

+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
 logger = logging.getLogger(__name__)

 id_server_scheme = "https://"
@@ -61,7 +67,7 @@ FIVE_MINUTES_IN_MS = 5 * 60 * 1000


 class RoomCreationHandler(BaseHandler):
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
        super(RoomCreationHandler, self).__init__(hs)

        self.spam_checker = hs.get_spam_checker()
@@ -92,7 +98,7 @@ class RoomCreationHandler(BaseHandler):
                "guest_can_join": False,
                "power_level_content_override": {},
            },
-        }
+        }  # type: Dict[str, Dict[str, Any]]

        # Modify presets to selectively enable encryption by default per homeserver config
        for preset_name, preset_config in self._presets_dict.items():
@@ -215,6 +221,9 @@ class RoomCreationHandler(BaseHandler):

        old_room_state = await tombstone_context.get_current_state_ids()

+        # We know the tombstone event isn't an outlier so it has current state.
+        assert old_room_state is not None
+
        # update any aliases
        await self._move_aliases_to_new_room(
            requester, old_room_id, new_room_id, old_room_state
@@ -528,17 +537,21 @@ class RoomCreationHandler(BaseHandler):
            logger.error("Unable to send updated alias events in new room: %s", e)

    async def create_room(
-        self, requester, config, ratelimit=True, creator_join_profile=None
+        self,
+        requester: Requester,
+        config: JsonDict,
+        ratelimit: bool = True,
+        creator_join_profile: Optional[JsonDict] = None,
    ) -> Tuple[dict, int]:
        """ Creates a new room.

        Args:
-            requester (synapse.types.Requester):
+            requester:
                The user who requested the room creation.
-            config (dict) : A dict of configuration options.
-            ratelimit (bool): set to False to disable the rate limiter
+            config : A dict of configuration options.
+            ratelimit: set to False to disable the rate limiter

-            creator_join_profile (dict|None):
+            creator_join_profile:
                Set to override the displayname and avatar for the creating
                user in this room. If unset, displayname and avatar will be
                derived from the user's profile. If set, should contain the
@@ -601,6 +614,7 @@ class RoomCreationHandler(BaseHandler):
                Codes.UNSUPPORTED_ROOM_VERSION,
            )

+        room_alias = None
        if "room_alias_name" in config:
            for wchar in string.whitespace:
                if wchar in config["room_alias_name"]:
@@ -611,8 +625,6 @@ class RoomCreationHandler(BaseHandler):

            if mapping:
                raise SynapseError(400, "Room alias already taken", Codes.ROOM_IN_USE)
-        else:
-            room_alias = None

        invite_list = config.get("invite", [])
        for i in invite_list:
@@ -771,23 +783,30 @@ class RoomCreationHandler(BaseHandler):

    async def _send_events_for_new_room(
        self,
-        creator,  # A Requester object.
-        room_id,
-        preset_config,
-        invite_list,
-        initial_state,
-        creation_content,
-        room_alias=None,
-        power_level_content_override=None,  # Doesn't apply when initial state has power level state event content
-        creator_join_profile=None,
+        creator: Requester,
+        room_id: str,
+        preset_config: str,
+        invite_list: List[str],
+        initial_state: StateMap,
+        creation_content: JsonDict,
+        room_alias: Optional[RoomAlias] = None,
+        power_level_content_override: Optional[JsonDict] = None,
+        creator_join_profile: Optional[JsonDict] = None,
    ) -> int:
        """Sends the initial events into a new room.

+        `power_level_content_override` doesn't apply when initial state has
+        power level state event content.
+
        Returns:
            The stream_id of the last event persisted.
        """

-        def create(etype, content, **kwargs):
+        creator_id = creator.user.to_string()
+
+        event_keys = {"room_id": room_id, "sender": creator_id, "state_key": ""}
+
+        def create(etype: str, content: JsonDict, **kwargs) -> JsonDict:
            e = {"type": etype, "content": content}

            e.update(event_keys)
@@ -795,7 +814,7 @@ class RoomCreationHandler(BaseHandler):

            return e

-        async def send(etype, content, **kwargs) -> int:
+        async def send(etype: str, content: JsonDict, **kwargs) -> int:
            event = create(etype, content, **kwargs)
            logger.debug("Sending %s in new room", etype)
            (
@@ -808,10 +827,6 @@ class RoomCreationHandler(BaseHandler):

        config = self._presets_dict[preset_config]

-        creator_id = creator.user.to_string()
-
-        event_keys = {"room_id": room_id, "sender": creator_id, "state_key": ""}
-
        creation_content.update({"creator": creator_id})
        await send(etype=EventTypes.Create, content=creation_content)

@@ -852,7 +867,7 @@ class RoomCreationHandler(BaseHandler):
                "kick": 50,
                "redact": 50,
                "invite": 50,
-            }
+            }  # type: JsonDict

            if config["original_invitees_have_ops"]:
                for invitee in invite_list:
@@ -906,7 +921,7 @@ class RoomCreationHandler(BaseHandler):
        return last_sent_stream_id

    async def _generate_room_id(
-        self, creator_id: str, is_public: str, room_version: RoomVersion,
+        self, creator_id: str, is_public: bool, room_version: RoomVersion,
    ):
        # autogen room IDs and try to create it. We may clash, so just
        # try a few times till one goes through, giving up eventually.
@@ -930,23 +945,30 @@ class RoomCreationHandler(BaseHandler):


 class RoomContextHandler(object):
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
        self.hs = hs
        self.store = hs.get_datastore()
        self.storage = hs.get_storage()
        self.state_store = self.storage.state

-    async def get_event_context(self, user, room_id, event_id, limit, event_filter):
+    async def get_event_context(
+        self,
+        user: UserID,
+        room_id: str,
+        event_id: str,
+        limit: int,
+        event_filter: Optional[Filter],
+    ) -> Optional[JsonDict]:
        """Retrieves events, pagination tokens and state around a given event
        in a room.

        Args:
-            user (UserID)
-            room_id (str)
-            event_id (str)
-            limit (int): The maximum number of events to return in total
+            user
+            room_id
+            event_id
+            limit: The maximum number of events to return in total
                (excluding state).
-            event_filter (Filter|None): the filter to apply to the events returned
+            event_filter: the filter to apply to the events returned
                (excluding the target event_id)

        Returns:
@@ -1033,15 +1055,21 @@ class RoomContextHandler(object):


 class RoomEventSource(object):
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
        self.store = hs.get_datastore()

    async def get_new_events(
-        self, user, from_key, limit, room_ids, is_guest, explicit_room_id=None
-    ):
+        self,
+        user: UserID,
+        from_key: str,
+        limit: int,
+        room_ids: List[str],
+        is_guest: bool,
+        explicit_room_id: Optional[str] = None,
+    ) -> Tuple[List[EventBase], str]:
        # We just ignore the key for now.

-        to_key = await self.get_current_key()
+        to_key = self.get_current_key()

        from_token = RoomStreamToken.parse(from_key)
        if from_token.topological:
@@ -1081,10 +1109,10 @@ class RoomEventSource(object):

        return (events, end_key)

-    def get_current_key(self):
-        return self.store.get_room_events_max_id()
+    def get_current_key(self) -> str:
+        return "s%d" % (self.store.get_room_max_stream_ordering(),)

-    def get_current_key_for_room(self, room_id):
+    def get_current_key_for_room(self, room_id: str) -> Awaitable[str]:
        return self.store.get_room_events_max_id(room_id)


@@ -1096,7 +1124,7 @@ class RoomShutdownHandler(object):
    )
    DEFAULT_ROOM_NAME = "Content Violation Notification"

-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
        self.hs = hs
        self.room_member_handler = hs.get_room_member_handler()
        self._room_creation_handler = hs.get_room_creation_handler()
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -16,13 +16,14 @@
 import abc
 import logging
 from http import HTTPStatus
-from typing import Dict, Iterable, List, Optional, Tuple, Union
+from typing import TYPE_CHECKING, Dict, Iterable, List, Optional, Tuple, Union

 from unpaddedbase64 import encode_base64

 from synapse import types
 from synapse.api.constants import MAX_DEPTH, EventTypes, Membership
-from synapse.api.errors import AuthError, Codes, SynapseError
+from synapse.api.errors import AuthError, Codes, LimitExceededError, 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
@@ -36,6 +37,10 @@ from synapse.util.distributor import user_joined_room, user_left_room

 from ._base import BaseHandler

+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
+
 logger = logging.getLogger(__name__)


@@ -47,7 +52,7 @@ class RoomMemberHandler(object):

    __metaclass__ = abc.ABCMeta

-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
        self.hs = hs
        self.store = hs.get_datastore()
        self.auth = hs.get_auth()
@@ -77,6 +82,17 @@ class RoomMemberHandler(object):
        if self._is_on_event_persistence_instance:
            self.persist_event_storage = hs.get_storage().persistence

+        self._join_rate_limiter_local = Ratelimiter(
+            clock=self.clock,
+            rate_hz=hs.config.ratelimiting.rc_joins_local.per_second,
+            burst_count=hs.config.ratelimiting.rc_joins_local.burst_count,
+        )
+        self._join_rate_limiter_remote = Ratelimiter(
+            clock=self.clock,
+            rate_hz=hs.config.ratelimiting.rc_joins_remote.per_second,
+            burst_count=hs.config.ratelimiting.rc_joins_remote.burst_count,
+        )
+
        # This is only used to get at ratelimit function, and
        # maybe_kick_guest_users. It's fine there are multiple of these as
        # it doesn't store state.
@@ -195,7 +211,7 @@ class RoomMemberHandler(object):
            return duplicate.event_id, stream_id

        stream_id = await self.event_creation_handler.handle_new_client_event(
-            requester, event, context, extra_users=[target], ratelimit=ratelimit
+            requester, event, context, extra_users=[target], ratelimit=ratelimit,
        )

        prev_state_ids = await context.get_prev_state_ids()
@@ -441,7 +457,28 @@ class RoomMemberHandler(object):
                    # so don't really fit into the general auth process.
                    raise AuthError(403, "Guest access not allowed")

-            if not is_host_in_room:
+            if is_host_in_room:
+                time_now_s = self.clock.time()
+                allowed, time_allowed = self._join_rate_limiter_local.can_do_action(
+                    requester.user.to_string(),
+                )
+
+                if not allowed:
+                    raise LimitExceededError(
+                        retry_after_ms=int(1000 * (time_allowed - time_now_s))
+                    )
+
+            else:
+                time_now_s = self.clock.time()
+                allowed, time_allowed = self._join_rate_limiter_remote.can_do_action(
+                    requester.user.to_string(),
+                )
+
+                if not allowed:
+                    raise LimitExceededError(
+                        retry_after_ms=int(1000 * (time_allowed - time_now_s))
+                    )
+
                inviter = await self._get_inviter(target.to_string(), room_id)
                if inviter and not self.hs.is_mine(inviter):
                    remote_room_hosts.append(inviter.domain)
@@ -469,26 +506,39 @@ class RoomMemberHandler(object):
                    user_id=target.to_string(), room_id=room_id
                )  # type: Optional[RoomsForUser]
                if not invite:
+                    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",
+                        target,
+                        room_id,
+                    )
+
                    raise SynapseError(404, "Not a known room")

                logger.info(
                    "%s rejects invite to %s from %s", target, room_id, invite.sender
                )

-                if self.hs.is_mine_id(invite.sender):
-                    # the inviter was on our server, but has now left. Carry on
-                    # with the normal rejection codepath.
-                    #
-                    # This is a bit of a hack, because the room might still be
-                    # active on other servers.
-                    pass
-                else:
+                if not self.hs.is_mine_id(invite.sender):
                    # send the rejection to the inviter's HS (with fallback to
                    # local event)
                    return await self.remote_reject_invite(
                        invite.event_id, txn_id, requester, content,
                    )

+                # the inviter was on our server, but has now left. Carry on
+                # with the normal rejection codepath, which will also send the
+                # rejection out to any other servers we believe are still in the room.
+
+                # thanks to overzealous cleaning up of event_forward_extremities in
+                # `delete_old_current_state_events`, it's possible to end up with no
+                # forward extremities here. If that happens, let's just hang the
+                # rejection off the invite event.
+                #
+                # see: https://github.com/matrix-org/synapse/issues/7139
+                if len(latest_event_ids) == 0:
+                    latest_event_ids = [invite.event_id]
+
        return await self._local_membership_update(
            requester=requester,
            target=target,
@@ -952,7 +1002,11 @@ class RoomMemberMasterHandler(RoomMemberHandler):
        if len(remote_room_hosts) == 0:
            raise SynapseError(404, "No known servers")

-        if self.hs.config.limit_remote_rooms.enabled:
+        check_complexity = self.hs.config.limit_remote_rooms.enabled
+        if check_complexity and self.hs.config.limit_remote_rooms.admins_can_join:
+            check_complexity = not await self.auth.is_server_admin(user)
+
+        if check_complexity:
            # Fetch the room complexity
            too_complex = await self._is_remote_room_too_complex(
                room_id, remote_room_hosts
@@ -975,7 +1029,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):

        # Check the room we just joined wasn't too large, if we didn't fetch the
        # complexity of it before.
-        if self.hs.config.limit_remote_rooms.enabled:
+        if check_complexity:
            if too_complex is False:
                # We checked, and we're under the limit.
                return event_id, stream_id
--- a/synapse/handlers/saml_handler.py
+++ b/synapse/handlers/saml_handler.py
@@ -14,15 +14,16 @@
 # limitations under the License.
 import logging
 import re
-from typing import Callable, Dict, Optional, Set, Tuple
+from typing import TYPE_CHECKING, Callable, Dict, Optional, Set, Tuple

 import attr
 import saml2
 import saml2.response
 from saml2.client import Saml2Client

-from synapse.api.errors import SynapseError
+from synapse.api.errors import AuthError, SynapseError
 from synapse.config import ConfigError
+from synapse.config.saml2_config import SamlAttributeRequirement
 from synapse.http.servlet import parse_string
 from synapse.http.site import SynapseRequest
 from synapse.module_api import ModuleApi
@@ -34,6 +35,9 @@ from synapse.types import (
 from synapse.util.async_helpers import Linearizer
 from synapse.util.iterutils import chunk_seq

+if TYPE_CHECKING:
+    import synapse.server
+
 logger = logging.getLogger(__name__)


@@ -49,7 +53,7 @@ class Saml2SessionData:


 class SamlHandler:
-    def __init__(self, hs):
+    def __init__(self, hs: "synapse.server.HomeServer"):
        self._saml_client = Saml2Client(hs.config.saml2_sp_config)
        self._auth = hs.get_auth()
        self._auth_handler = hs.get_auth_handler()
@@ -62,6 +66,7 @@ class SamlHandler:
        self._grandfathered_mxid_source_attribute = (
            hs.config.saml2_grandfathered_mxid_source_attribute
        )
+        self._saml2_attribute_requirements = hs.config.saml2.attribute_requirements

        # plugin to do custom mapping from saml response to mxid
        self._user_mapping_provider = hs.config.saml2_user_mapping_provider_class(
@@ -73,7 +78,7 @@ class SamlHandler:
        self._auth_provider_id = "saml"

        # a map from saml session id to Saml2SessionData object
-        self._outstanding_requests_dict = {}
+        self._outstanding_requests_dict = {}  # type: Dict[str, Saml2SessionData]

        # a lock on the mappings
        self._mapping_lock = Linearizer(name="saml_mapping", clock=self._clock)
@@ -96,6 +101,9 @@ class SamlHandler:
            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()
        self._outstanding_requests_dict[reqid] = Saml2SessionData(
            creation_time=now, ui_auth_session_id=ui_auth_session_id,
@@ -162,11 +170,18 @@ class SamlHandler:
                saml2.BINDING_HTTP_POST,
                outstanding=self._outstanding_requests_dict,
            )
+        except saml2.response.UnsolicitedResponse as e:
+            # the pysaml2 library helpfully logs an ERROR here, but neglects to log
+            # the session ID. I don't really want to put the full text of the exception
+            # 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))
+            raise SynapseError(400, "Unexpected SAML2 login.")
        except Exception as e:
-            raise SynapseError(400, "Unable to parse SAML2 response: %s" % (e,))
+            raise SynapseError(400, "Unable to parse SAML2 response: %s." % (e,))

        if saml2_auth.not_signed:
-            raise SynapseError(400, "SAML2 response was not signed")
+            raise SynapseError(400, "SAML2 response was not signed.")

        logger.debug("SAML2 response: %s", saml2_auth.origxml)
        for assertion in saml2_auth.assertions:
@@ -185,6 +200,9 @@ class SamlHandler:
            saml2_auth.in_response_to, None
        )

+        for requirement in self._saml2_attribute_requirements:
+            _check_attribute_requirement(saml2_auth.ava, requirement)
+
        remote_user_id = self._user_mapping_provider.get_remote_user_id(
            saml2_auth, client_redirect_url
        )
@@ -291,6 +309,21 @@ class SamlHandler:
            del self._outstanding_requests_dict[reqid]


+def _check_attribute_requirement(ava: dict, req: SamlAttributeRequirement):
+    values = ava.get(req.attribute, [])
+    for v in values:
+        if v == req.value:
+            return
+
+    logger.info(
+        "SAML2 attribute %s did not match required value '%s' (was '%s')",
+        req.attribute,
+        req.value,
+        values,
+    )
+    raise AuthError(403, "You are not authorized to log in here.")
+
+
 DOT_REPLACE_PATTERN = re.compile(
    ("[^%s]" % (re.escape("".join(mxid_localpart_allowed_characters)),))
 )
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -340,7 +340,7 @@ class SearchHandler(BaseHandler):
        # If client has asked for "context" for each event (i.e. some surrounding
        # events and state), fetch that
        if event_context is not None:
-            now_token = await self.hs.get_event_sources().get_current_token()
+            now_token = self.hs.get_event_sources().get_current_token()

            contexts = {}
            for event in allowed_events:
--- a/synapse/handlers/stats.py
+++ b/synapse/handlers/stats.py
@@ -232,7 +232,7 @@ class StatsHandler:

                if membership == prev_membership:
                    pass  # noop
-                if membership == Membership.JOIN:
+                elif membership == Membership.JOIN:
                    room_stats_delta["joined_members"] += 1
                elif membership == Membership.INVITE:
                    room_stats_delta["invited_members"] += 1
--- a/Show More
+++ b/Show More
				`@@ -0,0 +1 @@`
				`Fix a memory leak by limiting the length of time that messages will be queued for a remote server that has been unreachable.`
				`@@ -0,0 +1 @@`
				`Iteratively encode JSON to avoid blocking the reactor.`
				`@@ -0,0 +1 @@`
				`Use the default template file when its equivalent is not found in a custom template directory.`
				`@@ -0,0 +1 @@`
				`Convert various parts of the codebase to async/await.`
				`@@ -0,0 +1 @@`
				Fix `Re-starting finished log context PUT-nnnn` warning when event persistence failed.
				`@@ -0,0 +1 @@`
				`Add support for shadow-banning users (ignoring any message send requests).`
				`@@ -0,0 +1 @@`
				`Return the previous stream token if a non-member event is a duplicate.`
				`@@ -0,0 +1 @@`
				Synapse now correctly enforces the valid characters in the `client_secret` parameter used in various endpoints.
				`@@ -0,0 +1 @@`
				`Link to matrix-synapse-rest-password-provider in the password provider documentation.`