Ruff v0.16.0 releases with major updates including 413 default rules enabled (up from 59), covering 968 total rules. The expanded default set catches severe issues like syntax and runtime errors without configuration. Users can revert to old defaults via select configuration.

New features include Markdown code block formatting for Python snippets in .md and .qmd files, supporting fenced blocks with python, py, py3, pyi, pycon info strings. Ruff now offers native suppression comments: `ruff: ignore` for line-level, `ruff: disable/enable` for ranges, and `ruff: file-ignore` for file-level suppression, with automatic `--add-ignore` CLI support.

Linter and formatter fixes now display diffs inline in default output for `check` and `format --check`, with JSON output changes (fields may be null). 13 rules stabilized including airflow3-incompatible-function-signature (AIR303), missing-copyright-notice (CPY001), and various RUF/PLE/PLR rules. Additional behavior stabilizations improve BLE001, FA102, INT001-003, S310, S508, S509, UP019.