Synapse 1.148.0rc1 (2026-02-17)

Features

• Support sending and receiving MSC4354 Sticky Event metadata. (#19365)

Improved Documentation

• Fix reference to the experimental_features section of the configuration manual documentation. (#19435)

Deprecations and Removals

• Remove support for MSC3244: Room version capabilities as the MSC was rejected. (#19429)

Internal Changes

• Add in-repo Complement tests so we can test Synapse specific behavior at an end-to-end level. (#19406)
• Push Synapse docker images to Element OCI Registry. (#19420)
• Allow configuring the Rust HTTP client to use HTTP/2 only. (#19457)
• Correctly refuse to start if the Rust workspace config has changed and the Rust library has not been rebuilt. (#19470)