Sourced from black's releases.

26.3.1

Stable style

• Prevent Jupyter notebook magic masking collisions from corrupting cells by using exact-length placeholders for short magics and aborting if a placeholder can no longer be unmasked safely (#5038)

Configuration

• Always hash cache filename components derived from --python-cell-magics so custom magic names cannot affect cache paths (#5038)

Blackd

• Disable browser-originated requests by default, add configurable origin allowlisting and request body limits, and bound executor submissions to improve backpressure (#5039)

26.3.0

Stable style

• Don't double-decode input, causing non-UTF-8 files to be corrupted (#4964)
• Fix crash on standalone comment in lambda default arguments (#4993)
• Preserve parentheses when # type: ignore comments would be merged with other comments on the same line, preventing AST equivalence failures (#4888)

Preview style

• Fix bug where if guards in case blocks were incorrectly split when the pattern had a trailing comma (#4884)
• Fix string_processing crashing on unassigned long string literals with trailing commas (one-item tuples) (#4929)
• Simplify implementation of the power operator "hugging" logic (#4918)

Packaging

• Fix shutdown errors in PyInstaller builds on macOS by disabling multiprocessing in frozen environments (#4930)

Performance

• Introduce winloop for windows as an alternative to uvloop (#4996)
• Remove deprecated function uvloop.install() in favor of uvloop.new_event_loop() (#4996)
• Rename maybe_install_uvloop function to maybe_use_uvloop to simplify loop installation and creation of either a uvloop/winloop evenloop or default eventloop (#4996)

Output

... (truncated)

Sourced from black's changelog.

Version 26.3.1

Stable style

• Prevent Jupyter notebook magic masking collisions from corrupting cells by using exact-length placeholders for short magics and aborting if a placeholder can no longer be unmasked safely (#5038)

Configuration

• Always hash cache filename components derived from --python-cell-magics so custom magic names cannot affect cache paths (#5038)

Blackd

• Disable browser-originated requests by default, add configurable origin allowlisting and request body limits, and bound executor submissions to improve backpressure (#5039)

Version 26.3.0

Stable style

• Don't double-decode input, causing non-UTF-8 files to be corrupted (#4964)
• Fix crash on standalone comment in lambda default arguments (#4993)
• Preserve parentheses when # type: ignore comments would be merged with other comments on the same line, preventing AST equivalence failures (#4888)

Preview style

• Fix bug where if guards in case blocks were incorrectly split when the pattern had a trailing comma (#4884)
• Fix string_processing crashing on unassigned long string literals with trailing commas (one-item tuples) (#4929)
• Simplify implementation of the power operator "hugging" logic (#4918)

Packaging

• Fix shutdown errors in PyInstaller builds on macOS by disabling multiprocessing in frozen environments (#4930)

Performance

• Introduce winloop for windows as an alternative to uvloop (#4996)
• Remove deprecated function uvloop.install() in favor of uvloop.new_event_loop() (#4996)
• Rename maybe_install_uvloop function to maybe_use_uvloop to simplify loop installation and creation of either a uvloop/winloop eventloop or default eventloop (#4996)

... (truncated)

• c6755bb Prepare release 26.3.1 (#5046)
• 69973fd Harden blackd browser-facing request handling (#5039)
• 4937fe6 Fix some shenanigans with the cache file and IPython (#5038)
• 2e641d1 docs: remove outdated Black Playground references (#5044)
• c014b22 Remove unused internal code (#5041)
• 0dae20b Add new changelog (#5036)
• c5c1cbd Minor release patches (#5035)
• 7e5a828 docs: clarify relationship between Black style and PEP 8 (#5025)
• 69705de docs: add clearer pyproject configuration guidance (#5026)
• 35ea679 Prepare release 26.3.0 (#5032)
• Additional commits viewable in compare view

Sourced from mypy's changelog.

Mypy Release Notes

Next Release

Enabling --local-partial-types by default

This flag affects the inference of types based on assignments in other scopes. For now, explicitly disabling this continues to be supported, but this support will be removed in the future as the legacy behaviour is hard to support with other current and future features in mypy, like the daemon or the new implementation of flexible redefinitions.

Contributed by Ivan Levkivskyi, Jukka Lehtosalo, Shantanu in PR 21163

Enabling --strict-bytes by default

Per PEP 688, mypy no longer treats bytearray and memoryview values as assignable to the bytes type.

Contributed by Shantanu in PR 18371

Drop Support for Targeting Python 3.9

Mypy no longer supports type checking code with --python-version 3.9. Use --python-version 3.10 or newer.

Contributed by Shantanu, Marc Mueller in PR 21243

Remove special casing of legacy bundled stubs

Mypy used to bundle stubs for a few packages in versions 0.812 and earlier. To navigate the transition, mypy used to report missing types for these packages even if --ignore-missing-imports was set. Mypy now consistently respects --ignore-missing-imports for all packages.

Contributed by Shantanu in PR 18372

Prevent assignment to None for non-Optional class variables with type comments

Mypy used to allow assignment to None for class variables when using type comments. This was a common idiom in Python 3.5 and earlier, prior to the introduction of variable annotations. However, this was a soundness hole and has now been removed.

Contributed by Shantanu in PR 20054

Mypy 1.20

We’ve just uploaded mypy 1.20.0 to the Python Package Index (PyPI). Mypy is a static type checker for Python. This release includes new features, performance improvements and bug fixes. You can install it as follows:

python3 -m pip install -U mypy

... (truncated)

• 145a062 Bump version to 1.20.2
• 81cd492 Fix slicing with nonstrict optional (#21282)
• 908d344 [mypyc] Set dunder attrs when adding module to sys.modules (#21275)
• ba28610 Initial support for Python 3.15.0a8 (#21255)
• 7b0e09f Fix match statement semantics for "or" pattern (#21156)
• 92b74f2 Avoid widening types in conditional_types (#21242)
• 0dcbfaa Fix is_overlapping_types for generic callables (#21208)
• 210f518 Correctly aggregate narrowing information on parent expressions (#21206)
• c34530e Only set journal mode in coordinator (#21217)
• 79a3ec6 Use WAL with SQLite cache, fix close (#21154)
• Additional commits viewable in compare view

Sourced from nox's releases.

2026.04.10 🧹

This release drops Python 3.8 and adds a --usage command for full docstrings. Our .nox dir is now ignored by default, virtualenvs are recreated if symlinks are broken (such as after a Python upgrade), and -t now selects from all available sessions.

We'd like to thank the following folks who contributed to this release:

• @​henryiii
• @​agriyakhetarpal
• @​scop

Features:

• Drop Python 3.8 (reapply #1004) by @​henryiii in wntrblm/nox#1062
• Add a nox --usage <session> command to print full docstrings for provided sessions by @​agriyakhetarpal in wntrblm/nox#1064
• Write out .gitignore/CACHEDIR.TAG to .nox dir by @​henryiii in wntrblm/nox#1072

Fixes:

• Recreate venv if broken symlinks are present by @​henryiii in wntrblm/nox#1078
• Ignore default selection for tags and keywords by @​henryiii in wntrblm/nox#1057
• More uv variables set by @​henryiii in wntrblm/nox#1056
• Ignore forcecolor falsy by @​henryiii in wntrblm/nox#1073
• Fully pin actions in composite action by @​henryiii in wntrblm/nox#1080

Internal changes:

• Pin CI to working conda version by @​henryiii in wntrblm/nox#1079
• Use prek by @​agriyakhetarpal in wntrblm/nox#1065
• Switch artifact attestations to actions/attest by @​scop in wntrblm/nox#1070
• Use zizmor by @​henryiii in wntrblm/nox#1082

Full Changelog: wntrblm/nox@2026.02.09...2026.04.10

Sourced from nox's changelog.

Changelog

2026.04.10

This release drops Python 3.8 and adds a --usage command for full docstrings. Our .nox dir is now ignored by default, virtualenvs are recreated if symlinks are broken (such as after a Python upgrade), and -t now selects from all available sessions.

We'd like to thank the following folks who contributed to this release:

• @​henryiii
• @​agriyakhetarpal
• @​scop

Features:

• Drop Python 3.8 (reapply #1004) by @​henryiii in wntrblm/nox#1062
• Add a nox --usage <session> command to print full docstrings for provided sessions by @​agriyakhetarpal in wntrblm/nox#1064
• Write out .gitignore/CACHEDIR.TAG to .nox dir by @​henryiii in wntrblm/nox#1072

Fixes:

• Recreate venv if broken symlinks are present by @​henryiii in wntrblm/nox#1078
• Ignore default selection for tags and keywords by @​henryiii in wntrblm/nox#1057
• More uv variables set by @​henryiii in wntrblm/nox#1056
• Ignore forcecolor falsy by @​henryiii in wntrblm/nox#1073
• Fully pin actions in composite action by @​henryiii in wntrblm/nox#1080

Internal changes:

• Pin CI to working conda version by @​henryiii in wntrblm/nox#1079
• Use prek by @​agriyakhetarpal in wntrblm/nox#1065
• Switch artifact attestations to actions/attest by @​scop in wntrblm/nox#1070
• Use zizmor by @​henryiii in wntrblm/nox#1082

2026.02.09

This small release supports uv 0.10's new requirement that --clear be passed to clear an environment. Python 3.8 support was temporarily re-added since uv 0.10 still supports 3.8, so nox on 3.8 was affected.

We'd like to thank the following folks who contributed to this release:

• @​henryiii
• @​kai687 (first contribution)
• @​wu-zhao-min (first contribution)

... (truncated)

• 97e345e docs: add thanks section (#1083)
• 8d5c759 chore: prepare for 2026.04.10 (#1081)
• 2577f31 ci: add zizmor (#1082)
• b6a6156 fix: fully pin actions in composite action (#1080)
• 4c7a215 fix: write out .gitignore/CACHEDIR.TAG to our dir (#1072)
• 47cb9c3 fix: ignore default selection for tags and keywords (#1057)
• 63dcab9 fix: more uv variables set (#1056)
• e0f64e6 fix: recreate if broken symlinks are present (#1078)
• bf90952 tests: pin to working conda version (#1079)
• 4ff681f fix: ignore forcecolor falsy (#1073)
• Additional commits viewable in compare view