Synapse 1.56.0 (2022-04-05)

===========================

Synapse will now refuse to start up if open registration is enabled, in order to help mitigate
abuse across the federation. If you would like
to provide registration to anyone, consider adding [email](https://github.com/matrix-org/synapse/blob/8a519f8abc6de772167c2cca101d22ee2052fafc/docs/sample_config.yaml#L1285),
[recaptcha](https://matrix-org.github.io/synapse/v1.56/CAPTCHA_SETUP.html)
or [token-based](https://matrix-org.github.io/synapse/v1.56/usage/administration/admin_api/registration_tokens.html) verification
in order to prevent automated registration from bad actors.
This check can be disabled by setting the `enable_registration_without_verification` option in your
homeserver configuration file to `true`. More details are available in the
[upgrade notes](https://matrix-org.github.io/synapse/v1.56/upgrade.html#open-registration-without-verification-is-now-disabled-by-default).

Synapse will additionally now refuse to start when using PostgreSQL with a non-`C` values for `COLLATE` and `CTYPE`, unless
the config flag `allow_unsafe_locale`, found in the database section of the configuration file, is set to `true`. See the
[upgrade notes](https://matrix-org.github.io/synapse/v1.56/upgrade#change-in-behaviour-for-postgresql-databases-with-unsafe-locale)
for details.

Internal Changes
----------------

- Bump the version of `black` for compatibility with the latest `click` release. ([\matrix-org#12320](matrix-org#12320))

Synapse 1.56.0rc1 (2022-03-29)
==============================

Features
--------

- Allow modules to store already existing 3PID associations. ([\matrix-org#12195](matrix-org#12195))
- Allow registering server administrators using the module API. Contributed by Famedly. ([\matrix-org#12250](matrix-org#12250))

Bugfixes
--------

- Fix a long-standing bug which caused the `/_matrix/federation/v1/state` and `/_matrix/federation/v1/state_ids` endpoints to return incorrect or invalid data when called for an event which we have stored as an "outlier". ([\matrix-org#12087](matrix-org#12087))
- Fix a long-standing bug where events from ignored users would still be considered for relations. ([\matrix-org#12227](matrix-org#12227), [\matrix-org#12232](matrix-org#12232), [\matrix-org#12285](matrix-org#12285))
- Fix a bug introduced in Synapse 1.53.0 where an unnecessary query could be performed when fetching bundled aggregations for threads. ([\matrix-org#12228](matrix-org#12228))
- Fix a bug introduced in Synapse 1.52.0 where admins could not deactivate and GDPR-erase a user if Synapse was configured with limits on avatars. ([\matrix-org#12261](matrix-org#12261))

Improved Documentation
----------------------

- Fix the link to the module documentation in the legacy spam checker warning message. ([\matrix-org#12231](matrix-org#12231))
- Remove incorrect prefixes in the worker documentation for some endpoints. ([\matrix-org#12243](matrix-org#12243))
- Correct `check_username_for_spam` annotations and docs. ([\matrix-org#12246](matrix-org#12246))
- Correct Authentik OpenID typo, and add notes on troubleshooting. Contributed by @IronTooch. ([\matrix-org#12275](matrix-org#12275))
- HAProxy reverse proxy guide update to stop sending IPv4-mapped address to homeserver. Contributed by @villepeh. ([\matrix-org#12279](matrix-org#12279))

Internal Changes
----------------

- Rename `shared_rooms` to `mutual_rooms` ([MSC2666](matrix-org/matrix-spec-proposals#2666)), as per proposal changes. ([\matrix-org#12036](matrix-org#12036))
- Remove check on `update_user_directory` for shared rooms handler ([MSC2666](matrix-org/matrix-spec-proposals#2666)), and update/expand documentation. ([\matrix-org#12038](matrix-org#12038))
- Refactor `create_new_client_event` to use a new parameter, `state_event_ids`, which accurately describes the usage with [MSC2716](matrix-org/matrix-spec-proposals#2716) instead of abusing `auth_event_ids`. ([\matrix-org#12083](matrix-org#12083), [\matrix-org#12304](matrix-org#12304))
- Refuse to start if registration is enabled without email, captcha, or token-based verification unless the new config flag `enable_registration_without_verification` is set to `true`. ([\matrix-org#12091](matrix-org#12091), [\matrix-org#12322](matrix-org#12322))
- Add tests for database transaction callbacks. ([\matrix-org#12198](matrix-org#12198))
- Handle cancellation in `DatabasePool.runInteraction`. ([\matrix-org#12199](matrix-org#12199))
- Add missing type hints for cache storage. ([\matrix-org#12216](matrix-org#12216))
- Add missing type hints for storage. ([\matrix-org#12248](matrix-org#12248), [\matrix-org#12255](matrix-org#12255))
- Add type hints to tests files. ([\matrix-org#12224](matrix-org#12224), [\matrix-org#12240](matrix-org#12240), [\matrix-org#12256](matrix-org#12256))
- Use type stubs for `psycopg2`. ([\matrix-org#12269](matrix-org#12269))
- Improve type annotations for `execute_values`. ([\matrix-org#12311](matrix-org#12311))
- Clean-up logic around rebasing URLs for URL image previews. ([\matrix-org#12219](matrix-org#12219))
- Use the `ignored_users` table in additional places instead of re-parsing the account data. ([\matrix-org#12225](matrix-org#12225))
- Refactor the relations endpoints to add a `RelationsHandler`. ([\matrix-org#12237](matrix-org#12237))
- Generate announcement links in the release script. ([\matrix-org#12242](matrix-org#12242))
- Improve error message when dependencies check finds a broken installation. ([\matrix-org#12244](matrix-org#12244))
- Compress metrics HTTP resource when enabled. Contributed by Nick @ Beeper. ([\matrix-org#12258](matrix-org#12258))
- Refuse to start if the PostgreSQL database has a non-`C` locale, unless the config flag `allow_unsafe_db_locale` is set to true. ([\matrix-org#12262](matrix-org#12262), [\matrix-org#12288](matrix-org#12288))
- Optionally include account validity expiration information to experimental [MSC3720](matrix-org/matrix-spec-proposals#3720) account status responses. ([\matrix-org#12266](matrix-org#12266))
- Add a new cache `_get_membership_from_event_id` to speed up push rule calculations in large rooms. ([\matrix-org#12272](matrix-org#12272))
- Re-enable Complement concurrency in CI. ([\matrix-org#12283](matrix-org#12283))
- Remove unused test utilities. ([\matrix-org#12291](matrix-org#12291))
- Enhance logging for inbound federation events. ([\matrix-org#12301](matrix-org#12301))
- Fix compatibility with the recently-released Jinja 3.1. ([\matrix-org#12313](matrix-org#12313))
- Avoid trying to calculate the state at outlier events. ([\matrix-org#12314](matrix-org#12314))

Synapse 1.56.0rc1 (2022-03-29)

==============================

Features
--------

- Allow modules to store already existing 3PID associations. ([\matrix-org#12195](matrix-org#12195))
- Allow registering server administrators using the module API. Contributed by Famedly. ([\matrix-org#12250](matrix-org#12250))

Bugfixes
--------

- Fix a long-standing bug which caused the `/_matrix/federation/v1/state` and `/_matrix/federation/v1/state_ids` endpoints to return incorrect or invalid data when called for an event which we have stored as an "outlier". ([\matrix-org#12087](matrix-org#12087))
- Fix a long-standing bug where events from ignored users would still be considered for relations. ([\matrix-org#12227](matrix-org#12227), [\matrix-org#12232](matrix-org#12232), [\matrix-org#12285](matrix-org#12285))
- Fix a bug introduced in Synapse 1.53.0 where an unnecessary query could be performed when fetching bundled aggregations for threads. ([\matrix-org#12228](matrix-org#12228))
- Fix a bug introduced in Synapse 1.52.0 where admins could not deactivate and GDPR-erase a user if Synapse was configured with limits on avatars. ([\matrix-org#12261](matrix-org#12261))

Improved Documentation
----------------------

- Fix the link to the module documentation in the legacy spam checker warning message. ([\matrix-org#12231](matrix-org#12231))
- Remove incorrect prefixes in the worker documentation for some endpoints. ([\matrix-org#12243](matrix-org#12243))
- Correct `check_username_for_spam` annotations and docs. ([\matrix-org#12246](matrix-org#12246))
- Correct Authentik OpenID typo, and add notes on troubleshooting. Contributed by @IronTooch. ([\matrix-org#12275](matrix-org#12275))
- HAProxy reverse proxy guide update to stop sending IPv4-mapped address to homeserver. Contributed by @villepeh. ([\matrix-org#12279](matrix-org#12279))

Internal Changes
----------------

- Rename `shared_rooms` to `mutual_rooms` ([MSC2666](matrix-org/matrix-spec-proposals#2666)), as per proposal changes. ([\matrix-org#12036](matrix-org#12036))
- Remove check on `update_user_directory` for shared rooms handler ([MSC2666](matrix-org/matrix-spec-proposals#2666)), and update/expand documentation. ([\matrix-org#12038](matrix-org#12038))
- Refactor `create_new_client_event` to use a new parameter, `state_event_ids`, which accurately describes the usage with [MSC2716](matrix-org/matrix-spec-proposals#2716) instead of abusing `auth_event_ids`. ([\matrix-org#12083](matrix-org#12083), [\matrix-org#12304](matrix-org#12304))
- Refuse to start if registration is enabled without email, captcha, or token-based verification unless the new config flag `enable_registration_without_verification` is set. ([\matrix-org#12091](matrix-org#12091))
- Add tests for database transaction callbacks. ([\matrix-org#12198](matrix-org#12198))
- Handle cancellation in `DatabasePool.runInteraction`. ([\matrix-org#12199](matrix-org#12199))
- Add missing type hints for cache storage. ([\matrix-org#12216](matrix-org#12216))
- Add missing type hints for storage. ([\matrix-org#12248](matrix-org#12248), [\matrix-org#12255](matrix-org#12255))
- Add type hints to tests files. ([\matrix-org#12224](matrix-org#12224), [\matrix-org#12240](matrix-org#12240), [\matrix-org#12256](matrix-org#12256))
- Use type stubs for `psycopg2`. ([\matrix-org#12269](matrix-org#12269))
- Improve type annotations for `execute_values`. ([\matrix-org#12311](matrix-org#12311))
- Clean-up logic around rebasing URLs for URL image previews. ([\matrix-org#12219](matrix-org#12219))
- Use the `ignored_users` table in additional places instead of re-parsing the account data. ([\matrix-org#12225](matrix-org#12225))
- Refactor the relations endpoints to add a `RelationsHandler`. ([\matrix-org#12237](matrix-org#12237))
- Generate announcement links in the release script. ([\matrix-org#12242](matrix-org#12242))
- Improve error message when dependencies check finds a broken installation. ([\matrix-org#12244](matrix-org#12244))
- Compress metrics HTTP resource when enabled. Contributed by Nick @ Beeper. ([\matrix-org#12258](matrix-org#12258))
- Refuse to start if the PostgreSQL database has a non-`C` locale, unless the config flag `allow_unsafe_db_locale` is set to true. ([\matrix-org#12262](matrix-org#12262), [\matrix-org#12288](matrix-org#12288))
- Optionally include account validity expiration information to experimental [MSC3720](matrix-org/matrix-spec-proposals#3720) account status responses. ([\matrix-org#12266](matrix-org#12266))
- Add a new cache `_get_membership_from_event_id` to speed up push rule calculations in large rooms. ([\matrix-org#12272](matrix-org#12272))
- Re-enable Complement concurrency in CI. ([\matrix-org#12283](matrix-org#12283))
- Remove unused test utilities. ([\matrix-org#12291](matrix-org#12291))
- Enhance logging for inbound federation events. ([\matrix-org#12301](matrix-org#12301))
- Fix compatibility with the recently-released Jinja 3.1. ([\matrix-org#12313](matrix-org#12313))
- Avoid trying to calculate the state at outlier events. ([\matrix-org#12314](matrix-org#12314))

Synapse 1.55.2 (2022-03-24)

===========================

This patch version reverts the earlier fixes from Synapse 1.55.1, which could cause problems in certain deployments, and instead adds a cap to the version of Jinja to be installed. Again, this is to fix an incompatibility with version 3.1.0 of the [Jinja](https://pypi.org/project/Jinja2/) library, and again, deployments of Synapse using the `matrixdotorg/synapse` Docker image or Debian packages from packages.matrix.org are not affected.

Internal Changes
----------------

- Pin Jinja to <3.1.0, as Synapse fails to start with Jinja 3.1.0. ([\matrix-org#12297](matrix-org#12297))
- Revert changes from 1.55.1 as they caused problems with older versions of Jinja ([\matrix-org#12296](matrix-org#12296))

Synapse 1.55.1 (2022-03-24)

===========================

This is a patch release that fixes an incompatibility with version 3.1.0 of the [Jinja](https://pypi.org/project/Jinja2/) library, released on March 24th, 2022. Deployments of Synapse using the `matrixdotorg/synapse` Docker image or Debian packages from packages.matrix.org are not affected.

Internal Changes
----------------

- Remove uses of the long-deprecated `jinja2.Markup` which would prevent Synapse from starting with Jinja 3.1.0 or above installed. ([\matrix-org#12289](matrix-org#12289))

Synapse 1.55.0 (2022-03-22)

===========================

This release removes a workaround introduced in Synapse 1.50.0 for Mjolnir compatibility. **This breaks compatibility with Mjolnir 1.3.1 and earlier. ([\matrix-org#11700](matrix-org#11700; Mjolnir users should upgrade Mjolnir before upgrading Synapse to this version.

This release also moves the location of the `synctl` script; see the [upgrade notes](https://github.com/matrix-org/synapse/blob/develop/docs/upgrade.md#synctl-script-has-been-moved) for more details.

Internal Changes
----------------

- Tweak copy for default Single Sign-On account details template to better adhere to mobile app store guidelines. ([\matrix-org#12265](matrix-org#12265), [\matrix-org#12260](matrix-org#12260))

Synapse 1.55.0rc1 (2022-03-15)
==============================

Features
--------

- Add third-party rules callbacks `check_can_shutdown_room` and `check_can_deactivate_user`. ([\matrix-org#12028](matrix-org#12028))
- Improve performance of logging in for large accounts. ([\matrix-org#12132](matrix-org#12132))
- Add experimental env var `SYNAPSE_ASYNC_IO_REACTOR` that causes Synapse to use the asyncio reactor for Twisted. ([\matrix-org#12135](matrix-org#12135))
- Support the stable identifiers from [MSC3440](matrix-org/matrix-spec-proposals#3440): threads. ([\matrix-org#12151](matrix-org#12151))
- Add a new Jinja2 template filter to extract the local part of an email address. ([\matrix-org#12212](matrix-org#12212))

Bugfixes
--------

- Use the proper serialization format for bundled thread aggregations. The bug has existed since Synapse v1.48.0. ([\matrix-org#12090](matrix-org#12090))
- Fix a long-standing bug when redacting events with relations. ([\matrix-org#12113](matrix-org#12113), [\matrix-org#12121](matrix-org#12121), [\matrix-org#12130](matrix-org#12130), [\matrix-org#12189](matrix-org#12189))
- Fix a bug introduced in Synapse 1.7.2 whereby background updates are never run with the default background batch size. ([\matrix-org#12157](matrix-org#12157))
- Fix a bug where non-standard information was returned from the `/hierarchy` API. Introduced in Synapse v1.41.0. ([\matrix-org#12175](matrix-org#12175))
- Fix a bug introduced in Synapse 1.54.0 that broke background updates on sqlite homeservers while search was disabled. ([\matrix-org#12215](matrix-org#12215))
- Fix a long-standing bug when a `filter` argument with `event_fields` which did not include the `unsigned` field could result in a 500 error on `/sync`. ([\matrix-org#12234](matrix-org#12234))

Improved Documentation
----------------------

- Fix complexity checking config example in [Resource Constrained Devices](https://matrix-org.github.io/synapse/v1.54/other/running_synapse_on_single_board_computers.html) docs page. ([\matrix-org#11998](matrix-org#11998))
- Improve documentation for demo scripts. ([\matrix-org#12143](matrix-org#12143))
- Updates to the Room DAG concepts development document. ([\matrix-org#12179](matrix-org#12179))
- Document that the `typing`, `to_device`, `account_data`, `receipts`, and `presence` stream writer can only be used on a single worker. ([\matrix-org#12196](matrix-org#12196))
- Document that contributors can sign off privately by email. ([\matrix-org#12204](matrix-org#12204))

Deprecations and Removals
-------------------------

- **Remove workaround introduced in Synapse 1.50.0 for Mjolnir compatibility. Breaks compatibility with Mjolnir 1.3.1 and earlier. ([\matrix-org#11700](matrix-org#11700
- **`synctl` has been moved into into `synapse._scripts` and is exposed as an entry point; see [upgrade notes](https://github.com/matrix-org/synapse/blob/develop/docs/upgrade.md#synctl-script-has-been-moved). ([\matrix-org#12140](matrix-org#12140))
- Remove backwards compatibilty with pagination tokens from the `/relations` and `/aggregations` endpoints generated from Synapse < v1.52.0. ([\matrix-org#12138](matrix-org#12138))
- The groups/communities feature in Synapse has been deprecated. ([\matrix-org#12200](matrix-org#12200))

Internal Changes
----------------

- Simplify the `ApplicationService` class' set of public methods related to interest checking. ([\matrix-org#11915](matrix-org#11915))
- Add config settings for background update parameters. ([\matrix-org#11980](matrix-org#11980))
- Correct type hints for txredis. ([\matrix-org#12042](matrix-org#12042))
- Limit the size of `aggregation_key` on annotations. ([\matrix-org#12101](matrix-org#12101))
- Add type hints to tests files. ([\matrix-org#12108](matrix-org#12108), [\matrix-org#12146](matrix-org#12146), [\matrix-org#12207](matrix-org#12207), [\matrix-org#12208](matrix-org#12208))
- Move scripts to Synapse package and expose as setuptools entry points. ([\matrix-org#12118](matrix-org#12118))
- Add support for cancellation to `ReadWriteLock`. ([\matrix-org#12120](matrix-org#12120))
- Fix data validation to compare to lists, not sequences. ([\matrix-org#12128](matrix-org#12128))
- Fix CI not attaching source distributions and wheels to the GitHub releases. ([\matrix-org#12131](matrix-org#12131))
- Remove unused mocks from `test_typing`. ([\matrix-org#12136](matrix-org#12136))
- Give `scripts-dev` scripts suffixes for neater CI config. ([\matrix-org#12137](matrix-org#12137))
- Move the snapcraft configuration file to `contrib`. ([\matrix-org#12142](matrix-org#12142))
- Enable [MSC3030](matrix-org/matrix-spec-proposals#3030) Complement tests in CI. ([\matrix-org#12144](matrix-org#12144))
- Enable [MSC2716](matrix-org/matrix-spec-proposals#2716) Complement tests in CI. ([\matrix-org#12145](matrix-org#12145))
- Add test for `ObservableDeferred`'s cancellation behaviour. ([\matrix-org#12149](matrix-org#12149))
- Use `ParamSpec` in type hints for `synapse.logging.context`. ([\matrix-org#12150](matrix-org#12150))
- Prune unused jobs from `tox` config. ([\matrix-org#12152](matrix-org#12152))
- Move CI checks out of tox, to facilitate a move to using poetry. ([\matrix-org#12153](matrix-org#12153))
- Avoid generating state groups for local out-of-band leaves. ([\matrix-org#12154](matrix-org#12154))
- Avoid trying to calculate the state at outlier events. ([\matrix-org#12155](matrix-org#12155), [\matrix-org#12173](matrix-org#12173), [\matrix-org#12202](matrix-org#12202))
- Fix some type annotations. ([\matrix-org#12156](matrix-org#12156))
- Add type hints for `ObservableDeferred` attributes. ([\matrix-org#12159](matrix-org#12159))
- Use a prebuilt Action for the `tests-done` CI job. ([\matrix-org#12161](matrix-org#12161))
- Reduce number of DB queries made during processing of `/sync`. ([\matrix-org#12163](matrix-org#12163))
- Add `delay_cancellation` utility function, which behaves like `stop_cancellation` but waits until the original `Deferred` resolves before raising a `CancelledError`. ([\matrix-org#12180](matrix-org#12180))
- Retry HTTP replication failures, this should prevent 502's when restarting stateful workers (main, event persisters, stream writers). Contributed by Nick @ Beeper. ([\matrix-org#12182](matrix-org#12182))
- Add cancellation support to `@cached` and `@cachedList` decorators. ([\matrix-org#12183](matrix-org#12183))
- Remove unused variables. ([\matrix-org#12187](matrix-org#12187))
- Add combined test for HTTP pusher and push rule. Contributed by Nick @ Beeper. ([\matrix-org#12188](matrix-org#12188))
- Rename `HomeServer.get_tcp_replication` to `get_replication_command_handler`. ([\matrix-org#12192](matrix-org#12192))
- Remove some dead code. ([\matrix-org#12197](matrix-org#12197))
- Fix a misleading comment in the function `check_event_for_spam`. ([\matrix-org#12203](matrix-org#12203))
- Remove unnecessary `pass` statements. ([\matrix-org#12206](matrix-org#12206))
- Update the SSO username picker template to comply with SIWA guidelines. ([\matrix-org#12210](matrix-org#12210))
- Improve code documentation for the typing stream over replication. ([\matrix-org#12211](matrix-org#12211))

Synapse 1.55.0rc1 (2022-03-15)

==============================

This release removes a workaround introduced in Synapse 1.50.0 for Mjolnir compatibility. **This breaks compatibility with Mjolnir 1.3.1 and earlier. ([\matrix-org#11700](matrix-org#11700; Mjolnir users should upgrade Mjolnir before upgrading Synapse to this version.

Features
--------

- Add third-party rules callbacks `check_can_shutdown_room` and `check_can_deactivate_user`. ([\matrix-org#12028](matrix-org#12028))
- Improve performance of logging in for large accounts. ([\matrix-org#12132](matrix-org#12132))
- Add experimental env var `SYNAPSE_ASYNC_IO_REACTOR` that causes Synapse to use the asyncio reactor for Twisted. ([\matrix-org#12135](matrix-org#12135))
- Support the stable identifiers from [MSC3440](matrix-org/matrix-spec-proposals#3440): threads. ([\matrix-org#12151](matrix-org#12151))
- Add a new Jinja2 template filter to extract the local part of an email address. ([\matrix-org#12212](matrix-org#12212))

Bugfixes
--------

- Use the proper serialization format for bundled thread aggregations. The bug has existed since Synapse v1.48.0. ([\matrix-org#12090](matrix-org#12090))
- Fix a long-standing bug when redacting events with relations. ([\matrix-org#12113](matrix-org#12113), [\matrix-org#12121](matrix-org#12121), [\matrix-org#12130](matrix-org#12130), [\matrix-org#12189](matrix-org#12189))
- Fix a bug introduced in Synapse 1.7.2 whereby background updates are never run with the default background batch size. ([\matrix-org#12157](matrix-org#12157))
- Fix a bug where non-standard information was returned from the `/hierarchy` API. Introduced in Synapse v1.41.0. ([\matrix-org#12175](matrix-org#12175))
- Fix a bug introduced in Synapse 1.54.0 that broke background updates on sqlite homeservers while search was disabled. ([\matrix-org#12215](matrix-org#12215))
- Fix a long-standing bug when a `filter` argument with `event_fields` which did not include the `unsigned` field could result in a 500 error on `/sync`. ([\matrix-org#12234](matrix-org#12234))

Improved Documentation
----------------------

- Fix complexity checking config example in [Resource Constrained Devices](https://matrix-org.github.io/synapse/v1.54/other/running_synapse_on_single_board_computers.html) docs page. ([\matrix-org#11998](matrix-org#11998))
- Improve documentation for demo scripts. ([\matrix-org#12143](matrix-org#12143))
- Updates to the Room DAG concepts development document. ([\matrix-org#12179](matrix-org#12179))
- Document that the `typing`, `to_device`, `account_data`, `receipts`, and `presence` stream writer can only be used on a single worker. ([\matrix-org#12196](matrix-org#12196))
- Document that contributors can sign off privately by email. ([\matrix-org#12204](matrix-org#12204))

Deprecations and Removals
-------------------------

- **Remove workaround introduced in Synapse 1.50.0 for Mjolnir compatibility. Breaks compatibility with Mjolnir 1.3.1 and earlier. ([\matrix-org#11700](matrix-org#11700
- Remove backwards compatibilty with pagination tokens from the `/relations` and `/aggregations` endpoints generated from Synapse < v1.52.0. ([\matrix-org#12138](matrix-org#12138))
- The groups/communities feature in Synapse has been deprecated. ([\matrix-org#12200](matrix-org#12200))

Internal Changes
----------------

- Simplify the `ApplicationService` class' set of public methods related to interest checking. ([\matrix-org#11915](matrix-org#11915))
- Add config settings for background update parameters. ([\matrix-org#11980](matrix-org#11980))
- Correct type hints for txredis. ([\matrix-org#12042](matrix-org#12042))
- Limit the size of `aggregation_key` on annotations. ([\matrix-org#12101](matrix-org#12101))
- Add type hints to tests files. ([\matrix-org#12108](matrix-org#12108), [\matrix-org#12146](matrix-org#12146), [\matrix-org#12207](matrix-org#12207), [\matrix-org#12208](matrix-org#12208))
- Move scripts to Synapse package and expose as setuptools entry points. ([\matrix-org#12118](matrix-org#12118))
- Add support for cancellation to `ReadWriteLock`. ([\matrix-org#12120](matrix-org#12120))
- Fix data validation to compare to lists, not sequences. ([\matrix-org#12128](matrix-org#12128))
- Fix CI not attaching source distributions and wheels to the GitHub releases. ([\matrix-org#12131](matrix-org#12131))
- Remove unused mocks from `test_typing`. ([\matrix-org#12136](matrix-org#12136))
- Give `scripts-dev` scripts suffixes for neater CI config. ([\matrix-org#12137](matrix-org#12137))
- Move `synctl` into `synapse._scripts` and expose as an entry point. ([\matrix-org#12140](matrix-org#12140))
- Move the snapcraft configuration file to `contrib`. ([\matrix-org#12142](matrix-org#12142))
- Enable [MSC3030](matrix-org/matrix-spec-proposals#3030) Complement tests in CI. ([\matrix-org#12144](matrix-org#12144))
- Enable [MSC2716](matrix-org/matrix-spec-proposals#2716) Complement tests in CI. ([\matrix-org#12145](matrix-org#12145))
- Add test for `ObservableDeferred`'s cancellation behaviour. ([\matrix-org#12149](matrix-org#12149))
- Use `ParamSpec` in type hints for `synapse.logging.context`. ([\matrix-org#12150](matrix-org#12150))
- Prune unused jobs from `tox` config. ([\matrix-org#12152](matrix-org#12152))
- Move CI checks out of tox, to facilitate a move to using poetry. ([\matrix-org#12153](matrix-org#12153))
- Avoid generating state groups for local out-of-band leaves. ([\matrix-org#12154](matrix-org#12154))
- Avoid trying to calculate the state at outlier events. ([\matrix-org#12155](matrix-org#12155), [\matrix-org#12173](matrix-org#12173), [\matrix-org#12202](matrix-org#12202))
- Fix some type annotations. ([\matrix-org#12156](matrix-org#12156))
- Add type hints for `ObservableDeferred` attributes. ([\matrix-org#12159](matrix-org#12159))
- Use a prebuilt Action for the `tests-done` CI job. ([\matrix-org#12161](matrix-org#12161))
- Reduce number of DB queries made during processing of `/sync`. ([\matrix-org#12163](matrix-org#12163))
- Add `delay_cancellation` utility function, which behaves like `stop_cancellation` but waits until the original `Deferred` resolves before raising a `CancelledError`. ([\matrix-org#12180](matrix-org#12180))
- Retry HTTP replication failures, this should prevent 502's when restarting stateful workers (main, event persisters, stream writers). Contributed by Nick @ Beeper. ([\matrix-org#12182](matrix-org#12182))
- Add cancellation support to `@cached` and `@cachedList` decorators. ([\matrix-org#12183](matrix-org#12183))
- Remove unused variables. ([\matrix-org#12187](matrix-org#12187))
- Add combined test for HTTP pusher and push rule. Contributed by Nick @ Beeper. ([\matrix-org#12188](matrix-org#12188))
- Rename `HomeServer.get_tcp_replication` to `get_replication_command_handler`. ([\matrix-org#12192](matrix-org#12192))
- Remove some dead code. ([\matrix-org#12197](matrix-org#12197))
- Fix a misleading comment in the function `check_event_for_spam`. ([\matrix-org#12203](matrix-org#12203))
- Remove unnecessary `pass` statements. ([\matrix-org#12206](matrix-org#12206))
- Update the SSO username picker template to comply with SIWA guidelines. ([\matrix-org#12210](matrix-org#12210))
- Improve code documentation for the typing stream over replication. ([\matrix-org#12211](matrix-org#12211))

TODO note

Synapse 1.54.0 (2022-03-08)

===========================

Please note that this will be the last release of Synapse that is compatible with Mjolnir 1.3.1 and earlier.
Administrators of servers which have the Mjolnir module installed are advised to upgrade Mjolnir to version 1.3.2 or later.

Bugfixes
--------

- Fix a bug introduced in Synapse 1.54.0rc1 preventing the new module callbacks introduced in this release from being registered by modules. ([\matrix-org#12141](matrix-org#12141))
- Fix a bug introduced in Synapse 1.54.0rc1 where runtime dependency version checks would mistakenly check development dependencies if they were present and would not accept pre-release versions of dependencies. ([\matrix-org#12129](matrix-org#12129), [\matrix-org#12177](matrix-org#12177))

Internal Changes
----------------

- Update release script to insert the previous version when writing "No significant changes" line in the changelog. ([\matrix-org#12127](matrix-org#12127))
- Relax the version guard for "packaging" added in [\matrix-org#12088](matrix-org#12088). ([\matrix-org#12166](matrix-org#12166))

Synapse 1.54.0rc1 (2022-03-02)
==============================

Features
--------

- Add support for [MSC3202](matrix-org/matrix-spec-proposals#3202): sending one-time key counts and fallback key usage states to Application Services. ([\matrix-org#11617](matrix-org#11617))
- Improve the generated URL previews for some web pages. Contributed by @AndrewRyanChama. ([\matrix-org#11985](matrix-org#11985))
- Track cache invalidations in Prometheus metrics, as already happens for cache eviction based on size or time. ([\matrix-org#12000](matrix-org#12000))
- Implement experimental support for [MSC3720](matrix-org/matrix-spec-proposals#3720) (account status endpoints). ([\matrix-org#12001](matrix-org#12001), [\matrix-org#12067](matrix-org#12067))
- Enable modules to set a custom display name when registering a user. ([\matrix-org#12009](matrix-org#12009))
- Advertise Matrix 1.1 and 1.2 support on `/_matrix/client/versions`. ([\matrix-org#12020](matrix-org#12020), ([\matrix-org#12022](matrix-org#12022))
- Support only the stable identifier for [MSC3069](matrix-org/matrix-spec-proposals#3069 `is_guest` on `/_matrix/client/v3/account/whoami`. ([\matrix-org#12021](matrix-org#12021))
- Use room version 9 as the default room version (per [MSC3589](matrix-org/matrix-spec-proposals#3589)). ([\matrix-org#12058](matrix-org#12058))
- Add module callbacks to react to user deactivation status changes (i.e. deactivations and reactivations) and profile updates. ([\matrix-org#12062](matrix-org#12062))

Bugfixes
--------

- Fix a bug introduced in Synapse 1.48.0 where an edit of the latest event in a thread would not be properly applied to the thread summary. ([\matrix-org#11992](matrix-org#11992))
- Fix long-standing bug where the `get_rooms_for_user` cache was not correctly invalidated for remote users when the server left a room. ([\matrix-org#11999](matrix-org#11999))
- Fix a 500 error with Postgres when looking backwards with the [MSC3030](matrix-org/matrix-spec-proposals#3030) `/timestamp_to_event?dir=b` endpoint. ([\matrix-org#12024](matrix-org#12024))
- Properly fix a long-standing bug where wrong data could be inserted into the `event_search` table when using SQLite. This could block running `synapse_port_db` with an `argument of type 'int' is not iterable` error. This bug was partially fixed by a change in Synapse 1.44.0. ([\matrix-org#12037](matrix-org#12037))
- Fix slow performance of `/logout` in some cases where refresh tokens are in use. The slowness existed since the initial implementation of refresh tokens in version 1.38.0. ([\matrix-org#12056](matrix-org#12056))
- Fix a long-standing bug where Synapse would make additional failing requests over federation for missing data. ([\matrix-org#12077](matrix-org#12077))
- Fix occasional `Unhandled error in Deferred` error message. ([\matrix-org#12089](matrix-org#12089))
- Fix a bug introduced in Synapse 1.51.0 where incoming federation transactions containing at least one EDU would be dropped if debug logging was enabled for `synapse.8631_debug`. ([\matrix-org#12098](matrix-org#12098))
- Fix a long-standing bug which could cause push notifications to malfunction if `use_frozen_dicts` was set in the configuration. ([\matrix-org#12100](matrix-org#12100))
- Fix an extremely rare, long-standing bug in `ReadWriteLock` that would cause an error when a newly unblocked writer completes instantly. ([\matrix-org#12105](matrix-org#12105))
- Make a `POST` to `/rooms/<room_id>/receipt/m.read/<event_id>` only trigger a push notification if the count of unread messages is different to the one in the last successfully sent push. This reduces server load and load on the receiving device. ([\matrix-org#11835](matrix-org#11835))

Updates to the Docker image
---------------------------

- The Docker image no longer automatically creates a temporary volume at `/data`. This is not expected to affect normal usage. ([\matrix-org#11997](matrix-org#11997))
- Use Python 3.9 in Docker images by default. ([\matrix-org#12112](matrix-org#12112))

Improved Documentation
----------------------

- Document support for the `to_device`, `account_data`, `receipts`, and `presence` stream writers for workers. ([\matrix-org#11599](matrix-org#11599))
- Explain the meaning of spam checker callbacks' return values. ([\matrix-org#12003](matrix-org#12003))
- Clarify information about external Identity Provider IDs. ([\matrix-org#12004](matrix-org#12004))

Deprecations and Removals
-------------------------

- Deprecate using `synctl` with the config option `synctl_cache_factor` and print a warning if a user still uses this option. ([\matrix-org#11865](matrix-org#11865))
- Remove support for the legacy structured logging configuration (please see the the [upgrade notes](https://matrix-org.github.io/synapse/develop/upgrade#legacy-structured-logging-configuration-removal) if you are using `structured: true` in the Synapse configuration). ([\matrix-org#12008](matrix-org#12008))
- Drop support for [MSC3283](matrix-org/matrix-spec-proposals#3283) unstable flags now that the stable flags are supported. ([\matrix-org#12018](matrix-org#12018))
- Remove the unstable `/spaces` endpoint from [MSC2946](matrix-org/matrix-spec-proposals#2946). ([\matrix-org#12073](matrix-org#12073))

Internal Changes
----------------

- Make the `get_room_version` method use `get_room_version_id` to benefit from caching. ([\matrix-org#11808](matrix-org#11808))
- Remove unnecessary condition on knock -> leave auth rule check. ([\matrix-org#11900](matrix-org#11900))
- Add tests for device list changes between local users. ([\matrix-org#11972](matrix-org#11972))
- Optimise calculating `device_list` changes in `/sync`. ([\matrix-org#11974](matrix-org#11974))
- Add missing type hints to storage classes. ([\matrix-org#11984](matrix-org#11984))
- Refactor the search code for improved readability. ([\matrix-org#11991](matrix-org#11991))
- Move common deduplication code down into `_auth_and_persist_outliers`. ([\matrix-org#11994](matrix-org#11994))
- Limit concurrent joins from applications services. ([\matrix-org#11996](matrix-org#11996))
- Preparation for faster-room-join work: when parsing the `send_join` response, get the `m.room.create` event from `state`, not `auth_chain`. ([\matrix-org#12005](matrix-org#12005), [\matrix-org#12039](matrix-org#12039))
- Preparation for faster-room-join work: parse MSC3706 fields in send_join response. ([\matrix-org#12011](matrix-org#12011))
- Preparation for faster-room-join work: persist information on which events and rooms have partial state to the database. ([\matrix-org#12012](matrix-org#12012))
- Preparation for faster-room-join work: Support for calling `/federation/v1/state` on a remote server. ([\matrix-org#12013](matrix-org#12013))
- Configure `tox` to use `venv` rather than `virtualenv`. ([\matrix-org#12015](matrix-org#12015))
- Fix bug in `StateFilter.return_expanded()` and add some tests. ([\matrix-org#12016](matrix-org#12016))
- Use Matrix v1.1 endpoints (`/_matrix/client/v3/auth/...`) in fallback auth HTML forms. ([\matrix-org#12019](matrix-org#12019))
- Update the `olddeps` CI job to use an old version of `markupsafe`. ([\matrix-org#12025](matrix-org#12025))
- Upgrade Mypy to version 0.931. ([\matrix-org#12030](matrix-org#12030))
- Remove legacy `HomeServer.get_datastore()`. ([\matrix-org#12031](matrix-org#12031), [\matrix-org#12070](matrix-org#12070))
- Minor typing fixes. ([\matrix-org#12034](matrix-org#12034), [\matrix-org#12069](matrix-org#12069))
- After joining a room, create a dedicated logcontext to process the queued events. ([\matrix-org#12041](matrix-org#12041))
- Tidy up GitHub Actions config which builds distributions for PyPI. ([\matrix-org#12051](matrix-org#12051))
- Move configuration out of `setup.cfg`. ([\matrix-org#12052](matrix-org#12052), [\matrix-org#12059](matrix-org#12059))
- Fix error message when a worker process fails to talk to another worker process. ([\matrix-org#12060](matrix-org#12060))
- Fix using the `complement.sh` script without specifying a directory or a branch. Contributed by Nico on behalf of Famedly. ([\matrix-org#12063](matrix-org#12063))
- Add type hints to `tests/rest/client`. ([\matrix-org#12066](matrix-org#12066), [\matrix-org#12072](matrix-org#12072), [\matrix-org#12084](matrix-org#12084), [\matrix-org#12094](matrix-org#12094))
- Add some logging to `/sync` to try and track down matrix-org#11916. ([\matrix-org#12068](matrix-org#12068))
- Inspect application dependencies using `importlib.metadata` or its backport. ([\matrix-org#12088](matrix-org#12088))
- Use `assertEqual` instead of the deprecated `assertEquals` in test code. ([\matrix-org#12092](matrix-org#12092))
- Move experimental support for [MSC3440](matrix-org/matrix-spec-proposals#3440) to `/versions`. ([\matrix-org#12099](matrix-org#12099))
- Add `stop_cancellation` utility function to stop `Deferred`s from being cancelled. ([\matrix-org#12106](matrix-org#12106))
- Improve exception handling for concurrent execution. ([\matrix-org#12109](matrix-org#12109))
- Advertise support for Python 3.10 in packaging files. ([\matrix-org#12111](matrix-org#12111))
- Move CI checks out of tox, to facilitate a move to using poetry. ([\matrix-org#12119](matrix-org#12119))

Synapse 1.54.0rc1 (2022-03-02)

==============================

Please note that this will be the last release of Synapse that is compatible with Mjolnir 1.3.1 and earlier.
Administrators of servers which have the Mjolnir module installed are advised to upgrade Mjolnir to version 1.3.2 or later.

Features
--------

- Add support for [MSC3202](matrix-org/matrix-spec-proposals#3202): sending one-time key counts and fallback key usage states to Application Services. ([\matrix-org#11617](matrix-org#11617))
- Improve the generated URL previews for some web pages. Contributed by @AndrewRyanChama. ([\matrix-org#11985](matrix-org#11985))
- Track cache invalidations in Prometheus metrics, as already happens for cache eviction based on size or time. ([\matrix-org#12000](matrix-org#12000))
- Implement experimental support for [MSC3720](matrix-org/matrix-spec-proposals#3720) (account status endpoints). ([\matrix-org#12001](matrix-org#12001), [\matrix-org#12067](matrix-org#12067))
- Enable modules to set a custom display name when registering a user. ([\matrix-org#12009](matrix-org#12009))
- Advertise Matrix 1.1 and 1.2 support on `/_matrix/client/versions`. ([\matrix-org#12020](matrix-org#12020), ([\matrix-org#12022](matrix-org#12022))
- Support only the stable identifier for [MSC3069](matrix-org/matrix-spec-proposals#3069 `is_guest` on `/_matrix/client/v3/account/whoami`. ([\matrix-org#12021](matrix-org#12021))
- Use room version 9 as the default room version (per [MSC3589](matrix-org/matrix-spec-proposals#3589)). ([\matrix-org#12058](matrix-org#12058))
- Add module callbacks to react to user deactivation status changes (i.e. deactivations and reactivations) and profile updates. ([\matrix-org#12062](matrix-org#12062))

Bugfixes
--------

- Fix a bug introduced in Synapse 1.48.0 where an edit of the latest event in a thread would not be properly applied to the thread summary. ([\matrix-org#11992](matrix-org#11992))
- Fix long-standing bug where the `get_rooms_for_user` cache was not correctly invalidated for remote users when the server left a room. ([\matrix-org#11999](matrix-org#11999))
- Fix a 500 error with Postgres when looking backwards with the [MSC3030](matrix-org/matrix-spec-proposals#3030) `/timestamp_to_event?dir=b` endpoint. ([\matrix-org#12024](matrix-org#12024))
- Properly fix a long-standing bug where wrong data could be inserted into the `event_search` table when using SQLite. This could block running `synapse_port_db` with an `argument of type 'int' is not iterable` error. This bug was partially fixed by a change in Synapse 1.44.0. ([\matrix-org#12037](matrix-org#12037))
- Fix slow performance of `/logout` in some cases where refresh tokens are in use. The slowness existed since the initial implementation of refresh tokens in version 1.38.0. ([\matrix-org#12056](matrix-org#12056))
- Fix a long-standing bug where Synapse would make additional failing requests over federation for missing data. ([\matrix-org#12077](matrix-org#12077))
- Fix occasional `Unhandled error in Deferred` error message. ([\matrix-org#12089](matrix-org#12089))
- Fix a bug introduced in Synapse 1.51.0 where incoming federation transactions containing at least one EDU would be dropped if debug logging was enabled for `synapse.8631_debug`. ([\matrix-org#12098](matrix-org#12098))
- Fix a long-standing bug which could cause push notifications to malfunction if `use_frozen_dicts` was set in the configuration. ([\matrix-org#12100](matrix-org#12100))
- Fix an extremely rare, long-standing bug in `ReadWriteLock` that would cause an error when a newly unblocked writer completes instantly. ([\matrix-org#12105](matrix-org#12105))
- Make a `POST` to `/rooms/<room_id>/receipt/m.read/<event_id>` only trigger a push notification if the count of unread messages is different to the one in the last successfully sent push. This reduces server load and load on the receiving device. ([\matrix-org#11835](matrix-org#11835))

Updates to the Docker image
---------------------------

- The Docker image no longer automatically creates a temporary volume at `/data`. This is not expected to affect normal usage. ([\matrix-org#11997](matrix-org#11997))
- Use Python 3.9 in Docker images by default. ([\matrix-org#12112](matrix-org#12112))

Improved Documentation
----------------------

- Document support for the `to_device`, `account_data`, `receipts`, and `presence` stream writers for workers. ([\matrix-org#11599](matrix-org#11599))
- Explain the meaning of spam checker callbacks' return values. ([\matrix-org#12003](matrix-org#12003))
- Clarify information about external Identity Provider IDs. ([\matrix-org#12004](matrix-org#12004))

Deprecations and Removals
-------------------------

- Deprecate using `synctl` with the config option `synctl_cache_factor` and print a warning if a user still uses this option. ([\matrix-org#11865](matrix-org#11865))
- Remove support for the legacy structured logging configuration (please see the the [upgrade notes](https://matrix-org.github.io/synapse/develop/upgrade#legacy-structured-logging-configuration-removal) if you are using `structured: true` in the Synapse configuration). ([\matrix-org#12008](matrix-org#12008))
- Drop support for [MSC3283](matrix-org/matrix-spec-proposals#3283) unstable flags now that the stable flags are supported. ([\matrix-org#12018](matrix-org#12018))
- Remove the unstable `/spaces` endpoint from [MSC2946](matrix-org/matrix-spec-proposals#2946). ([\matrix-org#12073](matrix-org#12073))

Internal Changes
----------------

- Make the `get_room_version` method use `get_room_version_id` to benefit from caching. ([\matrix-org#11808](matrix-org#11808))
- Remove unnecessary condition on knock -> leave auth rule check. ([\matrix-org#11900](matrix-org#11900))
- Add tests for device list changes between local users. ([\matrix-org#11972](matrix-org#11972))
- Optimise calculating `device_list` changes in `/sync`. ([\matrix-org#11974](matrix-org#11974))
- Add missing type hints to storage classes. ([\matrix-org#11984](matrix-org#11984))
- Refactor the search code for improved readability. ([\matrix-org#11991](matrix-org#11991))
- Move common deduplication code down into `_auth_and_persist_outliers`. ([\matrix-org#11994](matrix-org#11994))
- Limit concurrent joins from applications services. ([\matrix-org#11996](matrix-org#11996))
- Preparation for faster-room-join work: when parsing the `send_join` response, get the `m.room.create` event from `state`, not `auth_chain`. ([\matrix-org#12005](matrix-org#12005), [\matrix-org#12039](matrix-org#12039))
- Preparation for faster-room-join work: parse MSC3706 fields in send_join response. ([\matrix-org#12011](matrix-org#12011))
- Preparation for faster-room-join work: persist information on which events and rooms have partial state to the database. ([\matrix-org#12012](matrix-org#12012))
- Preparation for faster-room-join work: Support for calling `/federation/v1/state` on a remote server. ([\matrix-org#12013](matrix-org#12013))
- Configure `tox` to use `venv` rather than `virtualenv`. ([\matrix-org#12015](matrix-org#12015))
- Fix bug in `StateFilter.return_expanded()` and add some tests. ([\matrix-org#12016](matrix-org#12016))
- Use Matrix v1.1 endpoints (`/_matrix/client/v3/auth/...`) in fallback auth HTML forms. ([\matrix-org#12019](matrix-org#12019))
- Update the `olddeps` CI job to use an old version of `markupsafe`. ([\matrix-org#12025](matrix-org#12025))
- Upgrade Mypy to version 0.931. ([\matrix-org#12030](matrix-org#12030))
- Remove legacy `HomeServer.get_datastore()`. ([\matrix-org#12031](matrix-org#12031), [\matrix-org#12070](matrix-org#12070))
- Minor typing fixes. ([\matrix-org#12034](matrix-org#12034), [\matrix-org#12069](matrix-org#12069))
- After joining a room, create a dedicated logcontext to process the queued events. ([\matrix-org#12041](matrix-org#12041))
- Tidy up GitHub Actions config which builds distributions for PyPI. ([\matrix-org#12051](matrix-org#12051))
- Move configuration out of `setup.cfg`. ([\matrix-org#12052](matrix-org#12052), [\matrix-org#12059](matrix-org#12059))
- Fix error message when a worker process fails to talk to another worker process. ([\matrix-org#12060](matrix-org#12060))
- Fix using the `complement.sh` script without specifying a directory or a branch. Contributed by Nico on behalf of Famedly. ([\matrix-org#12063](matrix-org#12063))
- Add type hints to `tests/rest/client`. ([\matrix-org#12066](matrix-org#12066), [\matrix-org#12072](matrix-org#12072), [\matrix-org#12084](matrix-org#12084), [\matrix-org#12094](matrix-org#12094))
- Add some logging to `/sync` to try and track down matrix-org#11916. ([\matrix-org#12068](matrix-org#12068))
- Inspect application dependencies using `importlib.metadata` or its backport. ([\matrix-org#12088](matrix-org#12088))
- Use `assertEqual` instead of the deprecated `assertEquals` in test code. ([\matrix-org#12092](matrix-org#12092))
- Move experimental support for [MSC3440](matrix-org/matrix-spec-proposals#3440) to `/versions`. ([\matrix-org#12099](matrix-org#12099))
- Add `stop_cancellation` utility function to stop `Deferred`s from being cancelled. ([\matrix-org#12106](matrix-org#12106))
- Improve exception handling for concurrent execution. ([\matrix-org#12109](matrix-org#12109))
- Advertise support for Python 3.10 in packaging files. ([\matrix-org#12111](matrix-org#12111))
- Move CI checks out of tox, to facilitate a move to using poetry. ([\matrix-org#12119](matrix-org#12119))

Synapse 1.53.0 (2022-02-22)

===========================

No significant changes.

Synapse 1.53.0rc1 (2022-02-15)
==============================

Features
--------

- Add experimental support for sending to-device messages to application services, as specified by [MSC2409](matrix-org/matrix-spec-proposals#2409). ([\matrix-org#11215](matrix-org#11215), [\matrix-org#11966](matrix-org#11966))
- Remove account data (including client config, push rules and ignored users) upon user deactivation. ([\matrix-org#11655](matrix-org#11655))
- Experimental support for [MSC3666](matrix-org/matrix-spec-proposals#3666): including bundled aggregations in server side search results. ([\matrix-org#11837](matrix-org#11837))
- Enable cache time-based expiry by default. The `expiry_time` config flag has been superseded by `expire_caches` and `cache_entry_ttl`. ([\matrix-org#11849](matrix-org#11849))
- Add a callback to allow modules to allow or forbid a 3PID (email address, phone number) from being associated to a local account. ([\matrix-org#11854](matrix-org#11854))
- Stabilize support and remove unstable endpoints for [MSC3231](matrix-org/matrix-spec-proposals#3231). Clients must switch to the stable identifier and endpoint. See the [upgrade notes](https://matrix-org.github.io/synapse/develop/upgrade#stablisation-of-msc3231) for more information. ([\matrix-org#11867](matrix-org#11867))
- Allow modules to retrieve the current instance's server name and worker name. ([\matrix-org#11868](matrix-org#11868))
- Use a dedicated configurable rate limiter for 3PID invites. ([\matrix-org#11892](matrix-org#11892))
- Support the stable API endpoint for [MSC3283](matrix-org/matrix-spec-proposals#3283): new settings in `/capabilities` endpoint. ([\matrix-org#11933](matrix-org#11933), [\matrix-org#11989](matrix-org#11989))
- Support the `dir` parameter on the `/relations` endpoint, per [MSC3715](matrix-org/matrix-spec-proposals#3715). ([\matrix-org#11941](matrix-org#11941))
- Experimental implementation of [MSC3706](matrix-org/matrix-spec-proposals#3706): extensions to `/send_join` to support reduced response size. ([\matrix-org#11967](matrix-org#11967))

Bugfixes
--------

- Fix [MSC2716](matrix-org/matrix-spec-proposals#2716) historical messages backfilling in random order on remote homeservers. ([\matrix-org#11114](matrix-org#11114))
- Fix a bug introduced in Synapse 1.51.0 where incoming federation transactions containing at least one EDU would be dropped if debug logging was enabled for `synapse.8631_debug`. ([\matrix-org#11890](matrix-org#11890))
- Fix a long-standing bug where some unknown endpoints would return HTML error pages instead of JSON `M_UNRECOGNIZED` errors. ([\matrix-org#11930](matrix-org#11930))
- Implement an allow list of content types for which we will attempt to preview a URL. This prevents Synapse from making useless longer-lived connections to streaming media servers. ([\matrix-org#11936](matrix-org#11936))
- Fix a long-standing bug where pagination tokens from `/sync` and `/messages` could not be provided to the `/relations` API. ([\matrix-org#11952](matrix-org#11952))
- Require that modules register their callbacks using keyword arguments. ([\matrix-org#11975](matrix-org#11975))
- Fix a long-standing bug where `M_WRONG_ROOM_KEYS_VERSION` errors would not include the specced `current_version` field. ([\matrix-org#11988](matrix-org#11988))

Improved Documentation
----------------------

- Fix typo in User Admin API: unpind -> unbind. ([\matrix-org#11859](matrix-org#11859))
- Document images returned by the User List Media Admin API can include those generated by URL previews. ([\matrix-org#11862](matrix-org#11862))
- Remove outdated MSC1711 FAQ document. ([\matrix-org#11907](matrix-org#11907))
- Correct the structured logging configuration example. Contributed by Brad Jones. ([\matrix-org#11946](matrix-org#11946))
- Add information on the Synapse release cycle. ([\matrix-org#11954](matrix-org#11954))
- Fix broken link in the README to the admin API for password reset. ([\matrix-org#11955](matrix-org#11955))

Deprecations and Removals
-------------------------

- Drop support for `webclient` listeners and configuring `web_client_location` to a non-HTTP(S) URL. Deprecated configurations are a configuration error. ([\matrix-org#11895](matrix-org#11895))
- Remove deprecated `user_may_create_room_with_invites` spam checker callback. See the [upgrade notes](https://matrix-org.github.io/synapse/latest/upgrade.html#removal-of-user_may_create_room_with_invites) for more information. ([\matrix-org#11950](matrix-org#11950))
- No longer build `.deb` packages for Ubuntu 21.04 Hirsute Hippo, which has now EOLed. ([\matrix-org#11961](matrix-org#11961))

Internal Changes
----------------

- Enhance user registration test helpers to make them more useful for tests involving application services and devices. ([\matrix-org#11615](matrix-org#11615), [\matrix-org#11616](matrix-org#11616))
- Improve performance when fetching bundled aggregations for multiple events. ([\matrix-org#11660](matrix-org#11660), [\matrix-org#11752](matrix-org#11752))
- Fix type errors introduced by new annotations in the Prometheus Client library. ([\matrix-org#11832](matrix-org#11832))
- Add missing type hints to replication code. ([\matrix-org#11856](matrix-org#11856), [\matrix-org#11938](matrix-org#11938))
- Ensure that `opentracing` scopes are activated and closed at the right time. ([\matrix-org#11869](matrix-org#11869))
- Improve opentracing for incoming federation requests. ([\matrix-org#11870](matrix-org#11870))
- Improve internal docstrings in `synapse.util.caches`. ([\matrix-org#11876](matrix-org#11876))
- Do not needlessly clear the `get_users_in_room` and `get_users_in_room_with_profiles` caches when any room state changes. ([\matrix-org#11878](matrix-org#11878))
- Convert `ApplicationServiceTestCase` to use `simple_async_mock`. ([\matrix-org#11880](matrix-org#11880))
- Remove experimental changes to the default push rules which were introduced in Synapse 1.19.0 but never enabled. ([\matrix-org#11884](matrix-org#11884))
- Disable coverage calculation for olddeps build. ([\matrix-org#11888](matrix-org#11888))
- Preparation to support sending device list updates to application services. ([\matrix-org#11905](matrix-org#11905))
- Add a test that checks users receive their own device list updates down `/sync`. ([\matrix-org#11909](matrix-org#11909))
- Run Complement tests sequentially. ([\matrix-org#11910](matrix-org#11910))
- Various refactors to the application service notifier code. ([\matrix-org#11911](matrix-org#11911), [\matrix-org#11912](matrix-org#11912))
- Tests: replace mocked `Authenticator` with the real thing. ([\matrix-org#11913](matrix-org#11913))
- Various refactors to the typing notifications code. ([\matrix-org#11914](matrix-org#11914))
- Use the proper type for the `Content-Length` header in the `UploadResource`. ([\matrix-org#11927](matrix-org#11927))
- Remove an unnecessary ignoring of type hints due to fixes in upstream packages. ([\matrix-org#11939](matrix-org#11939))
- Add missing type hints. ([\matrix-org#11953](matrix-org#11953))
- Fix an import cycle in `synapse.event_auth`. ([\matrix-org#11965](matrix-org#11965))
- Unpin `frozendict` but exclude the known bad version 2.1.2. ([\matrix-org#11969](matrix-org#11969))
- Prepare for rename of default Complement branch. ([\matrix-org#11971](matrix-org#11971))
- Fetch Synapse's version using a helper from `matrix-common`. ([\matrix-org#11979](matrix-org#11979))