Release Pillow 12.1.0 on January 2, 2026

[radarhere]

Main release

Released quarterly on January 2nd, April 1st, July 1st and October 15th.

• [ ] Open a release ticket e.g. https://github.com/python-pillow/Pillow/issues/3154
• [ ] Develop and prepare release in main branch.
  • [ ] Add release notes e.g. https://github.com/python-pillow/Pillow/pull/8885
• [ ] Check GitHub Actions to confirm passing tests in main branch.
• [ ] Check that all the wheel builds pass the tests in the GitHub Actions "Wheels" workflow jobs by manually triggering them.
• [ ] In compliance with PEP 440, update version identifier in src/PIL/_version.py
• [ ] Run pre-release check via make release-test in a freshly cloned repo.
• [ ] Create branch and tag for release e.g.:

  git branch 12.1.x
  git tag 12.1.0
  git push --tags
  

• [ ] Check the GitHub Actions "Wheels" workflow has passed, including the "Upload release to PyPI" job. This will have been triggered by the new tag.
• [ ] Publish the release on GitHub.
• [ ] In compliance with PEP 440, increment and append .dev0 to version identifier in src/PIL/_version.py and then:

  git push --all
  

Publicize release

• [ ] Announce release availability via Mastodon e.g. https://fosstodon.org/@pillow/110639450470725321

Documentation

• [ ] Make sure the default version for Read the Docs is up-to-date with the release changes

Docker images

• [ ] Update Pillow in the Docker Images repository

  git clone https://github.com/python-pillow/docker-images
  cd docker-images
  ./update-pillow-tag.sh 12.1.0