- Expose [MSC4354 Sticky Events](https://github.com/matrix-org/matrix-spec-proposals/pull/4354) over [MSC4186 (Simplified) Sliding Sync](https://github.com/matrix-org/matrix-spec-proposals/pull/4186). ([\#19591](https://github.com/element-hq/synapse/issues/19591)) - Stabilize support for sending ephemeral events to application services, as per [MSC2409](https://github.com/matrix-org/matrix-spec-proposals/pull/2409). Contributed by @jason-famedly @ Famedly. ([\#19758](https://github.com/element-hq/synapse/issues/19758)) - Include `allowed_room_ids` in the `/summary` client-server API response for rooms with restricted join rules, as required by Matrix 1.15. Contributed by @FrenchGithubUser @Famedly. ([\#19762](https://github.com/element-hq/synapse/issues/19762)) - [MSC4140: Cancellable delayed events](https://github.com/matrix-org/matrix-spec-proposals/pull/4140): Allow authentication on delayed event management endpoints (such as `/restart`) to bypass ratelimits for unauthenticated requests based on the client IP address. ([\#19794](https://github.com/element-hq/synapse/issues/19794)) - Add new metric `synapse_non_deactivated_user_count` which tracks the number of non-deactivated users in the database, split by `app_service`. ([\#19848](https://github.com/element-hq/synapse/issues/19848)) - The `GET /_matrix/client/unstable/org.matrix.msc1763/retention/configuration` endpoint is now provided when retention is enabled and `experimental_features.msc1763_enabled` is enabled, based on [MSC1763](https://github.com/matrix-org/matrix-spec-proposals/pull/1763). ([\#19853](https://github.com/element-hq/synapse/issues/19853)) - Add experimental support for [MSC4491: Invite reasons in room creation](https://github.com/matrix-org/matrix-spec-proposals/pull/4491). ([\#19874](https://github.com/element-hq/synapse/issues/19874)) - Provide remote servers a way to find out about an event created during the remote join handshake. Contributed by @FrenchGithubUser and @jason-famedly @ Famedly. ([\#19390](https://github.com/element-hq/synapse/issues/19390), [\#19855](https://github.com/element-hq/synapse/issues/19855), [\#19856](https://github.com/element-hq/synapse/issues/19856)) - Advertise `org.matrix.msc4143` in `unstable_features` when `msc4143_enabled` is set. ([\#19646](https://github.com/element-hq/synapse/issues/19646)) - Fix a long-standing bug where the badge notification count for a room could become permanently inflated if a read receipt was sent before the room's notification counts were first summarised. ([\#19785](https://github.com/element-hq/synapse/issues/19785)) - Fix startup listener logging to report the actual bound TCP port, so listeners configured with port `0` no longer log `Synapse now listening on TCP port 0`. ([\#19810](https://github.com/element-hq/synapse/issues/19810)) - Fix notification counts being inflated after a `/purge_history` when notifications had already been rotated into the summary table. ([\#19834](https://github.com/element-hq/synapse/issues/19834)) - Fix `/sync` caching transient errors for the `sync_response_cache_duration`. ([\#19845](https://github.com/element-hq/synapse/issues/19845)) - Fix local events being deleted by the [Purge History admin API](https://element-hq.github.io/synapse/v1.155/admin_api/purge_history_api.html) despite `delete_local_events` being set to false, in room versions other than 1 and 2. ([\#19850](https://github.com/element-hq/synapse/issues/19850)) - Fix a bug where a user's dehydrated device ([MSC3814](https://github.com/matrix-org/matrix-spec-proposals/pull/3814)) was deleted when their device list was synced from Matrix Authentication Service (e.g. upon logging out their last device), breaking offline key delivery. ([\#19892](https://github.com/element-hq/synapse/issues/19892)) - Update `auto_join_rooms` config documentation to cover requirements for auto-joining invite-only rooms. ([\#19660](https://github.com/element-hq/synapse/issues/19660)) - Add stable endpoint for [MSC3266: Room summary API](https://github.com/matrix-org/matrix-spec-proposals/pull/3266) into worker docs. Contributed by @olmari. ([\#19788](https://github.com/element-hq/synapse/issues/19788)) - Tweak wording of Rust crate dependency update policy. ([\#19829](https://github.com/element-hq/synapse/issues/19829)) - Fixed the Admin API user endpoint documentation examples to use JSON booleans (true/false) instead of numeric (0/1) values. ([\#19847](https://github.com/element-hq/synapse/issues/19847)) - Make `simple_select_one_onecol_txn()` more helpful by naming the table of the select - as all other query wrapper functions already did. ([\#19869](https://github.com/element-hq/synapse/issues/19869)) - Refactor `get_user_which_could_invite` logic to reuse `get_users_which_can_issue_invite`. Contributed by Noah Markert. ([\#19732](https://github.com/element-hq/synapse/issues/19732)) - Fix a flaky test (`twisted.protocols.amp.TooLong` error under `trial -jN`) caused by an oversized debug log line. ([\#19832](https://github.com/element-hq/synapse/issues/19832)) - Upload Complement test logs as CI artifacts instead of printing the raw output to the build log. ([\#19840](https://github.com/element-hq/synapse/issues/19840)) - Fix release script considering any workflow completion as successful. ([\#19843](https://github.com/element-hq/synapse/issues/19843)) - Force keyword-args for clear `default_config(server_name="test")` usage in test utilities. ([\#19849](https://github.com/element-hq/synapse/issues/19849)) - Add `.ruff_cache/` directory to `.gitignore`. ([\#19854](https://github.com/element-hq/synapse/issues/19854)) - Bump `poetry` in CI from `2.2.1` to `2.4.1`. ([\#19866](https://github.com/element-hq/synapse/issues/19866), [\#19877](https://github.com/element-hq/synapse/issues/19877)) - Split out `deferred` and `tokio_runtime` to their own Rust modules. ([\#19868](https://github.com/element-hq/synapse/issues/19868)) - Prevent the `cargo-test` and `cargo-bench` CI jobs from being skipped, even on PRs that have Rust changes. ([\#19883](https://github.com/element-hq/synapse/issues/19883))