diff --git a/.buildkite/worker-blacklist b/.buildkite/worker-blacklist
index d7908af177..7950d19db3 100644
--- a/.buildkite/worker-blacklist
+++ b/.buildkite/worker-blacklist
@@ -57,3 +57,10 @@ Don't get pushed for rooms you've muted
 Rejected events are not pushed
 Test that rejected pushers are removed.
 Events come down the correct room
+
+# https://buildkite.com/matrix-dot-org/sytest/builds/326#cca62404-a88a-4fcb-ad41-175fd3377603
+Presence changes to UNAVAILABLE are reported to remote room members
+If remote user leaves room, changes device and rejoins we see update in sync
+uploading self-signing key notifies over federation
+Inbound federation can receive redacted events
+Outbound federation can request missing events
diff --git a/changelog.d/6119.feature b/changelog.d/6119.feature
new file mode 100644
index 0000000000..1492e83c5a
--- /dev/null
+++ b/changelog.d/6119.feature
@@ -0,0 +1 @@
+Require User-Interactive Authentication for `/account/3pid/add`, meaning the user's password will be required to add a third-party ID to their account.
\ No newline at end of file
diff --git a/changelog.d/6241.bugfix b/changelog.d/6241.bugfix
new file mode 100644
index 0000000000..25109ca4a6
--- /dev/null
+++ b/changelog.d/6241.bugfix
@@ -0,0 +1 @@
+Fix error from the Pillow library when uploading RGBA images.
diff --git a/changelog.d/6434.feature b/changelog.d/6434.feature
new file mode 100644
index 0000000000..affa5d50c1
--- /dev/null
+++ b/changelog.d/6434.feature
@@ -0,0 +1 @@
+Add support for MSC 2367, which allows specifying a reason on all membership events.
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 270caacc09..3090bc72d7 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -1435,9 +1435,9 @@ class FederationHandler(BaseHandler):
         return event
 
     @defer.inlineCallbacks
-    def do_remotely_reject_invite(self, target_hosts, room_id, user_id):
+    def do_remotely_reject_invite(self, target_hosts, room_id, user_id, content):
         origin, event, event_format_version = yield self._make_and_verify_event(
-            target_hosts, room_id, user_id, "leave"
+            target_hosts, room_id, user_id, "leave", content=content,
         )
         # Mark as outlier as we don't have any state for this event; we're not
         # even in the room.
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 00440ca140..9a58c14eb7 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -99,7 +99,9 @@ class RoomMemberHandler(object):
         raise NotImplementedError()
 
     @abc.abstractmethod
-    def _remote_reject_invite(self, requester, remote_room_hosts, room_id, target):
+    def _remote_reject_invite(
+        self, requester, remote_room_hosts, room_id, target, content
+    ):
         """Attempt to reject an invite for a room this server is not in. If we
         fail to do so we locally mark the invite as rejected.
 
@@ -109,6 +111,7 @@ class RoomMemberHandler(object):
                 reject invite
             room_id (str)
             target (UserID): The user rejecting the invite
+            content (dict): The content for the rejection event
 
         Returns:
             Deferred[dict]: A dictionary to be returned to the client, may
@@ -526,7 +529,7 @@ class RoomMemberHandler(object):
                     # send the rejection to the inviter's HS.
                     remote_room_hosts = remote_room_hosts + [inviter.domain]
                     res = yield self._remote_reject_invite(
-                        requester, remote_room_hosts, room_id, target
+                        requester, remote_room_hosts, room_id, target, content,
                     )
                     return res
 
@@ -1056,13 +1059,15 @@ class RoomMemberMasterHandler(RoomMemberHandler):
             )
 
     @defer.inlineCallbacks
-    def _remote_reject_invite(self, requester, remote_room_hosts, room_id, target):
+    def _remote_reject_invite(
+        self, requester, remote_room_hosts, room_id, target, content
+    ):
         """Implements RoomMemberHandler._remote_reject_invite
         """
         fed_handler = self.federation_handler
         try:
             ret = yield fed_handler.do_remotely_reject_invite(
-                remote_room_hosts, room_id, target.to_string()
+                remote_room_hosts, room_id, target.to_string(), content=content,
             )
             return ret
         except Exception as e:
diff --git a/synapse/handlers/room_member_worker.py b/synapse/handlers/room_member_worker.py
index 75e96ae1a2..69be86893b 100644
--- a/synapse/handlers/room_member_worker.py
+++ b/synapse/handlers/room_member_worker.py
@@ -55,7 +55,9 @@ class RoomMemberWorkerHandler(RoomMemberHandler):
 
         return ret
 
-    def _remote_reject_invite(self, requester, remote_room_hosts, room_id, target):
+    def _remote_reject_invite(
+        self, requester, remote_room_hosts, room_id, target, content
+    ):
         """Implements RoomMemberHandler._remote_reject_invite
         """
         return self._remote_reject_client(
@@ -63,6 +65,7 @@ class RoomMemberWorkerHandler(RoomMemberHandler):
             remote_room_hosts=remote_room_hosts,
             room_id=room_id,
             user_id=target.to_string(),
+            content=content,
         )
 
     def _user_joined_room(self, target, room_id):
diff --git a/synapse/replication/http/membership.py b/synapse/replication/http/membership.py
index cc1f249740..3577611fd7 100644
--- a/synapse/replication/http/membership.py
+++ b/synapse/replication/http/membership.py
@@ -93,6 +93,7 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
         {
             "requester": ...,
             "remote_room_hosts": [...],
+            "content": { ... }
         }
     """
 
@@ -107,7 +108,7 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
         self.clock = hs.get_clock()
 
     @staticmethod
-    def _serialize_payload(requester, room_id, user_id, remote_room_hosts):
+    def _serialize_payload(requester, room_id, user_id, remote_room_hosts, content):
         """
         Args:
             requester(Requester)
@@ -118,12 +119,14 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
         return {
             "requester": requester.serialize(),
             "remote_room_hosts": remote_room_hosts,
+            "content": content,
         }
 
     async def _handle_request(self, request, room_id, user_id):
         content = parse_json_object_from_request(request)
 
         remote_room_hosts = content["remote_room_hosts"]
+        event_content = content["content"]
 
         requester = Requester.deserialize(self.store, content["requester"])
 
@@ -134,7 +137,7 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
 
         try:
             event = await self.federation_handler.do_remotely_reject_invite(
-                remote_room_hosts, room_id, user_id
+                remote_room_hosts, room_id, user_id, event_content,
             )
             ret = event.get_pdu_json()
         except Exception as e:
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 91846fe1d7..44517b179e 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -715,7 +715,7 @@ class RoomMembershipRestServlet(TransactionRestServlet):
             target = UserID.from_string(content["user_id"])
 
         event_content = None
-        if "reason" in content and membership_action in ["kick", "ban"]:
+        if "reason" in content:
             event_content = {"reason": content["reason"]}
 
         await self.room_member_handler.update_membership(
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index f71dc1410b..d396206bcb 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -725,6 +725,7 @@ class ThreepidAddRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.auth_handler = hs.get_auth_handler()
 
+    @interactive_auth_handler
     @defer.inlineCallbacks
     def on_POST(self, request):
         requester = yield self.auth.get_user_by_req(request)
@@ -735,6 +736,10 @@ class ThreepidAddRestServlet(RestServlet):
         client_secret = body["client_secret"]
         sid = body["sid"]
 
+        yield self.auth_handler.validate_user_via_ui_auth(
+            requester, body, self.hs.get_ip_from_request(request)
+        )
+
         validation_session = yield self.identity_handler.validate_threepid_session(
             client_secret, sid
         )
diff --git a/synapse/rest/media/v1/thumbnailer.py b/synapse/rest/media/v1/thumbnailer.py
index 8cf415e29d..c234ea7421 100644
--- a/synapse/rest/media/v1/thumbnailer.py
+++ b/synapse/rest/media/v1/thumbnailer.py
@@ -129,5 +129,8 @@ class Thumbnailer(object):
 
     def _encode_image(self, output_image, output_type):
         output_bytes_io = BytesIO()
-        output_image.save(output_bytes_io, self.FORMATS[output_type], quality=80)
+        fmt = self.FORMATS[output_type]
+        if fmt == "JPEG":
+            output_image = output_image.convert("RGB")
+        output_image.save(output_bytes_io, fmt, quality=80)
         return output_bytes_io
diff --git a/synapse/visibility.py b/synapse/visibility.py
index c0e39f5be6..dffe943b28 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -100,9 +100,9 @@ def filter_events_for_client(
         retention_policies = {}
 
         for room_id in room_ids:
-            retention_policies[room_id] = (
-                yield storage.main.get_retention_policy_for_room(room_id)
-            )
+            retention_policies[
+                room_id
+            ] = yield storage.main.get_retention_policy_for_room(room_id)
 
     def allowed(event):
         """
diff --git a/tests/rest/client/v1/test_rooms.py b/tests/rest/client/v1/test_rooms.py
index e84e578f99..eda2fabc71 100644
--- a/tests/rest/client/v1/test_rooms.py
+++ b/tests/rest/client/v1/test_rooms.py
@@ -1180,3 +1180,143 @@ class PerRoomProfilesForbiddenTestCase(unittest.HomeserverTestCase):
 
         res_displayname = channel.json_body["content"]["displayname"]
         self.assertEqual(res_displayname, self.displayname, channel.result)
+
+
+class RoomMembershipReasonTestCase(unittest.HomeserverTestCase):
+    """Tests that clients can add a "reason" field to membership events and
+    that they get correctly added to the generated events and propagated.
+    """
+
+    servlets = [
+        synapse.rest.admin.register_servlets_for_client_rest_resource,
+        room.register_servlets,
+        login.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, homeserver):
+        self.creator = self.register_user("creator", "test")
+        self.creator_tok = self.login("creator", "test")
+
+        self.second_user_id = self.register_user("second", "test")
+        self.second_tok = self.login("second", "test")
+
+        self.room_id = self.helper.create_room_as(self.creator, tok=self.creator_tok)
+
+    def test_join_reason(self):
+        reason = "hello"
+        request, channel = self.make_request(
+            "POST",
+            "/_matrix/client/r0/rooms/{}/join".format(self.room_id),
+            content={"reason": reason},
+            access_token=self.second_tok,
+        )
+        self.render(request)
+        self.assertEqual(channel.code, 200, channel.result)
+
+        self._check_for_reason(reason)
+
+    def test_leave_reason(self):
+        self.helper.join(self.room_id, user=self.second_user_id, tok=self.second_tok)
+
+        reason = "hello"
+        request, channel = self.make_request(
+            "POST",
+            "/_matrix/client/r0/rooms/{}/leave".format(self.room_id),
+            content={"reason": reason},
+            access_token=self.second_tok,
+        )
+        self.render(request)
+        self.assertEqual(channel.code, 200, channel.result)
+
+        self._check_for_reason(reason)
+
+    def test_kick_reason(self):
+        self.helper.join(self.room_id, user=self.second_user_id, tok=self.second_tok)
+
+        reason = "hello"
+        request, channel = self.make_request(
+            "POST",
+            "/_matrix/client/r0/rooms/{}/kick".format(self.room_id),
+            content={"reason": reason, "user_id": self.second_user_id},
+            access_token=self.second_tok,
+        )
+        self.render(request)
+        self.assertEqual(channel.code, 200, channel.result)
+
+        self._check_for_reason(reason)
+
+    def test_ban_reason(self):
+        self.helper.join(self.room_id, user=self.second_user_id, tok=self.second_tok)
+
+        reason = "hello"
+        request, channel = self.make_request(
+            "POST",
+            "/_matrix/client/r0/rooms/{}/ban".format(self.room_id),
+            content={"reason": reason, "user_id": self.second_user_id},
+            access_token=self.creator_tok,
+        )
+        self.render(request)
+        self.assertEqual(channel.code, 200, channel.result)
+
+        self._check_for_reason(reason)
+
+    def test_unban_reason(self):
+        reason = "hello"
+        request, channel = self.make_request(
+            "POST",
+            "/_matrix/client/r0/rooms/{}/unban".format(self.room_id),
+            content={"reason": reason, "user_id": self.second_user_id},
+            access_token=self.creator_tok,
+        )
+        self.render(request)
+        self.assertEqual(channel.code, 200, channel.result)
+
+        self._check_for_reason(reason)
+
+    def test_invite_reason(self):
+        reason = "hello"
+        request, channel = self.make_request(
+            "POST",
+            "/_matrix/client/r0/rooms/{}/invite".format(self.room_id),
+            content={"reason": reason, "user_id": self.second_user_id},
+            access_token=self.creator_tok,
+        )
+        self.render(request)
+        self.assertEqual(channel.code, 200, channel.result)
+
+        self._check_for_reason(reason)
+
+    def test_reject_invite_reason(self):
+        self.helper.invite(
+            self.room_id,
+            src=self.creator,
+            targ=self.second_user_id,
+            tok=self.creator_tok,
+        )
+
+        reason = "hello"
+        request, channel = self.make_request(
+            "POST",
+            "/_matrix/client/r0/rooms/{}/leave".format(self.room_id),
+            content={"reason": reason},
+            access_token=self.second_tok,
+        )
+        self.render(request)
+        self.assertEqual(channel.code, 200, channel.result)
+
+        self._check_for_reason(reason)
+
+    def _check_for_reason(self, reason):
+        request, channel = self.make_request(
+            "GET",
+            "/_matrix/client/r0/rooms/{}/state/m.room.member/{}".format(
+                self.room_id, self.second_user_id
+            ),
+            access_token=self.creator_tok,
+        )
+        self.render(request)
+        self.assertEqual(channel.code, 200, channel.result)
+
+        event_content = channel.json_body
+
+        self.assertEqual(event_content.get("reason"), reason, channel.result)