Released on 2026-04-09.

Preview features

• [flake8-logging] Allow closures in except handlers (LOG004) (#24464)
• [flake8-self] Make SLF diagnostics robust to non-self-named variables (#24281)
• [flake8-simplify] Make the fix for collapsible-if safe in preview (SIM102) (#24371)

Bug fixes

• Avoid emitting multi-line f-string elements before Python 3.12 (#24377)
• Avoid syntax error from E502 fixes in f-strings and t-strings (#24410)
• Strip form feeds from indent passed to dedent_to (#24381)
• [pyupgrade] Fix panic caused by handling of octals (UP012) (#24390)
• Reject multi-line f-string elements before Python 3.12 (#24355)

Rule changes

• [ruff] Treat f-string interpolation as potential side effect (RUF019) (#24426)

Server

• Add support for custom file extensions (#24463)

Documentation

• Document adding fixes in CONTRIBUTING.md (#24393)
• Fix JSON typo in settings example (#24517)