Release notes needed:

• Add TIFF compression codecs: LZMA, Zstd, WebP #3555
• Added support for I;16 modes for more transpose operations #3563?
  Do not resize in Image.thumbnail if already the destination size #3632?
• Added PPM mime types #3688

Main release checklist

• Open a release ticket
• Develop and prepare release in master branch.
• Check Travis CI and AppVeyor CI to confirm passing tests in master branch.
• Check that all of the wheel builds Pillow Wheel Builder pass the tests in Travis CI.
• In compliance with PEP 440, update version identifier in src/PIL/_version.py
• Update CHANGES.rst.
• Run pre-release check via make release-test in a freshly cloned repo.
• Create branch and tag for release e.g.:

    $ git branch 6.0.x
    $ git tag 6.0.0
    $ git push --all
    $ git push --tags

• Create source distributions e.g.:

    $ make sdist

• Create binary distributions
• Upload all binaries and source distributions e.g. twine upload dist/Pillow-6.0.0-*
• Create a new release on GitHub
• In compliance with PEP 440, append .dev0 to version identifier in src/PIL/_version.py

Binary Distributions

Windows

• Contact @cgohlke for Windows binaries via release ticket e.g. Release 2.9.0 on July 1, 2015 #1174.
• Download and extract tarball from @cgohlke and twine upload *.

Mac and Linux

• Use the Pillow Wheel Builder:

  git clone https://github.com/python-pillow/pillow-wheels
  cd pillow-wheels
  ./update-pillow-tag.sh 6.0.0

• Download distributions from the Pillow Wheel Builder container.

  wget -m -A 'Pillow-6.0.0*' \
  http://a365fff413fe338398b6-1c8a9b3114517dc5fe17b7c3f8c63a43.r19.cf2.rackcdn.com

Publicize Release

• Announce release availability via Twitter e.g. https://twitter.com/PythonPillow/status/1013789184354603010

Documentation

• Make sure the default version for Read the Docs is the latest release version, i.e. 6.0.0 rather than latest e.g. https://pillow.readthedocs.io/en/6.0.x/