- Support sending and receiving [MSC4354 Sticky Event](https://github.com/matrix-org/matrix-spec-proposals/pull/4354) metadata. ([\#19365](https://github.com/element-hq/synapse/issues/19365)) - Fix reference to the `experimental_features` section of the configuration manual documentation. ([\#19435](https://github.com/element-hq/synapse/issues/19435)) - Remove support for [MSC3244: Room version capabilities](https://github.com/matrix-org/matrix-spec-proposals/pull/3244) as the MSC was rejected. ([\#19429](https://github.com/element-hq/synapse/issues/19429)) - Add in-repo Complement tests so we can test Synapse specific behavior at an end-to-end level. ([\#19406](https://github.com/element-hq/synapse/issues/19406)) - Push Synapse docker images to Element OCI Registry. ([\#19420](https://github.com/element-hq/synapse/issues/19420)) - Allow configuring the Rust HTTP client to use HTTP/2 only. ([\#19457](https://github.com/element-hq/synapse/issues/19457)) - Correctly refuse to start if the Rust workspace config has changed and the Rust library has not been rebuilt. ([\#19470](https://github.com/element-hq/synapse/issues/19470))