Ruff 0.16.10

Ruff 0.16.10 landed on October 1, 2026. It is a patch release, so do not expect headline features. The real story is about memory, toolchain hygiene, and a new lint rule that will touch your codebase.

What Changed

The headline rule is UP052, a new pyupgrade check that flags context manager iterator annotations. If your code annotates the iterator of a with statement, this rule wants to modernize it. It will generate warnings on upgrade, so plan for it.

Performance and Safety

• Less memory - Diagnostics now use less memory, which helps on large repos.
• Safer server behavior - The language server no longer runs uv format in untrusted workspaces.

Dependencies Bumped

Ruff now builds on Rust 1.99 and raises its minimum supported Rust version to 1.97. Python 3.15 is documented as a supported version. Read the migration guide for the new lint categories before upgrading.

The upgrade is worth it for the memory win alone, but set aside time to review UP052 warnings.