- Add `msc4263_limit_key_queries_to_users_who_share_rooms` config option as per [MSC4263](https://github.com/matrix-org/matrix-spec-proposals/pull/4263). ([\#18180](https://github.com/element-hq/synapse/issues/18180)) - Add option to allow registrations that begin with `_`. Contributed by `_` (@hex5f). ([\#18262](https://github.com/element-hq/synapse/issues/18262)) - Include room ID in response to the [Room Deletion Status Admin API](https://element-hq.github.io/synapse/latest/admin_api/rooms.html#status-of-deleting-rooms). ([\#18318](https://github.com/element-hq/synapse/issues/18318)) - Add support for calling Policy Servers ([MSC4284](https://github.com/matrix-org/matrix-spec-proposals/pull/4284)) to mark events as spam. ([\#18387](https://github.com/element-hq/synapse/issues/18387)) - Prevent race-condition in `_maybe_retry_device_resync` entrance. ([\#18391](https://github.com/element-hq/synapse/issues/18391)) - Fix the `tests.handlers.test_worker_lock.WorkerLockTestCase.test_lock_contention` test which could spuriously time out on RISC-V architectures due to performance differences. ([\#18430](https://github.com/element-hq/synapse/issues/18430)) - Fix admin redaction endpoint not redacting encrypted messages. ([\#18434](https://github.com/element-hq/synapse/issues/18434)) - Update `room_list_publication_rules` docs to consider defaults that changed in v1.126.0. Contributed by @HarHarLinks. ([\#18286](https://github.com/element-hq/synapse/issues/18286)) - Add advice for upgrading between major PostgreSQL versions to the database documentation. ([\#18445](https://github.com/element-hq/synapse/issues/18445)) - Fix a memory leak in `_NotifierUserStream`. ([\#18380](https://github.com/element-hq/synapse/issues/18380)) - Fix a couple type annotations in the `RootConfig`/`Config`. ([\#18409](https://github.com/element-hq/synapse/issues/18409)) - Explicitly enable PyPy builds in `cibuildwheel`s config to avoid it being disabled on a future upgrade to `cibuildwheel` v3. ([\#18417](https://github.com/element-hq/synapse/issues/18417)) - Update the PR review template to remove an erroneous line break from the final bullet point. ([\#18419](https://github.com/element-hq/synapse/issues/18419)) - Explain why we `flush_buffer()` for Python `print(...)` output. ([\#18420](https://github.com/element-hq/synapse/issues/18420)) - Add lint to ensure we don't add a `CREATE/DROP INDEX` in a schema delta. ([\#18440](https://github.com/element-hq/synapse/issues/18440)) - Allow checking only for the existence of a field in an SSO provider's response, rather than requiring the value(s) to check. ([\#18454](https://github.com/element-hq/synapse/issues/18454)) - Add unit tests for homeserver usage statistics. ([\#18463](https://github.com/element-hq/synapse/issues/18463)) - Don't move invited users to new room when shutting down room. ([\#18471](https://github.com/element-hq/synapse/issues/18471)) * Bump actions/setup-python from 5.5.0 to 5.6.0. ([\#18398](https://github.com/element-hq/synapse/issues/18398)) * Bump authlib from 1.5.1 to 1.5.2. ([\#18452](https://github.com/element-hq/synapse/issues/18452)) * Bump docker/build-push-action from 6.15.0 to 6.17.0. ([\#18397](https://github.com/element-hq/synapse/issues/18397), [\#18449](https://github.com/element-hq/synapse/issues/18449)) * Bump lxml from 5.3.0 to 5.4.0. ([\#18480](https://github.com/element-hq/synapse/issues/18480)) * Bump mypy-zope from 1.0.9 to 1.0.11. ([\#18428](https://github.com/element-hq/synapse/issues/18428)) * Bump pyo3 from 0.23.5 to 0.24.2. ([\#18460](https://github.com/element-hq/synapse/issues/18460)) * Bump pyo3-log from 0.12.3 to 0.12.4. ([\#18453](https://github.com/element-hq/synapse/issues/18453)) * Bump pyopenssl from 25.0.0 to 25.1.0. ([\#18450](https://github.com/element-hq/synapse/issues/18450)) * Bump ruff from 0.7.3 to 0.11.11. ([\#18451](https://github.com/element-hq/synapse/issues/18451), [\#18482](https://github.com/element-hq/synapse/issues/18482)) * Bump tornado from 6.4.2 to 6.5.0. ([\#18459](https://github.com/element-hq/synapse/issues/18459)) * Bump setuptools from 72.1.0 to 78.1.1. ([\#18461](https://github.com/element-hq/synapse/issues/18461)) * Bump types-jsonschema from 4.23.0.20241208 to 4.23.0.20250516. ([\#18481](https://github.com/element-hq/synapse/issues/18481)) * Bump types-requests from 2.32.0.20241016 to 2.32.0.20250328. ([\#18427](https://github.com/element-hq/synapse/issues/18427))