Release cycle

  1. release every 3 months (at time T)

  2. T-11 weeks: all add your favorite Issues to the next-rel column

  3. T-10 weeks: Scrum Master prep dev meet (internal)

    • Update/trim next-release column in Kanban

    • Prepare agenda, include possible additions not covered by Kanban/Issues

    • Add milestone tags (nextver, nextver+1, etc.)

    • Add highlighted new features to

  4. T-8 weeks: Release Manager dev meet (external/public)

    • Use Kanban as starter

    • Move issues around based on input

    • Add milestone tags, for this release or future releases

    • Update highlighted new features to

  5. T-1: all reserve week for wrapping up PRs and review.

  6. T±0: Release Manager release!

    • Have a look at Python release schedule, and time Arbor release optimally with new Python minor version. It is nice to generate wheels for the new minor as soon as minor is released.

  7. T+1 weeks: Scrum Master retrospective

    • set date for next release


These notes enumerate the steps required every time we release a new version of Arbor.


Update tags/versions and test

  1. Check if some files are up to date


    • Verify (required for PyPI sdist)

    • Double check that all examples/tutorials/etc are covered by CI

    • Check Python/pip/PyPi metadata and scripts, e.g., pyproject.toml

  2. Create new temp-branch ending in -rc. E.g. v0.6-rc

  3. Bump the VERSION file:

  4. Run all tests.

    • ciwheel.yml triggers when you push a branch called ciwheel, and on new Git tags. Since we’ve not tagged the release yet, run git push origin HEAD:ciwheel. Make sure the tests pass.

      • ciwheel.yml pushes automatically to This only passes if ran as branch of the main arbor-sim repo (as that’s where the PyPI secret lives). On your own repo, the upload will fail (the rest should pass). If you want to test uploading, then force push to the _upstream_ ciwheel branch, e.g. git push upstream HEAD:ciwheel --force.

    • If you want to test the PyPI submission (consider asking other OS-users):

      python -m venv env && source env/bin/activate
      pip install numpy
      pip install -i arbor #should select the latest build, but doublecheck
      python -c 'import arbor; print(arbor.__config__)'
    • Use build flags to test the source package: Advanced options


  1. Make sure no errors were encountered in the pre-release phase, working wheels were produced, and were installable from and that no problems were reported.

  2. Change VERSION. Make sure does not end with -rc or -dev.

  3. Update scripts/ to check the current tag.

  4. Tag

    • commit and open a PR for the above changes.

    • on cmdline: git tag -a TAGNAME

    • git push upstream TAGNAME

  5. Upload to pypi & verify

    twine upload -r arborpypi dist/*
    python -m venv env && source env/bin/activate
    pip install arbor
    python -c 'import arbor; print(arbor.__config__)'
  6. Create tarball with scripts/create_tarball ~/loc/of/arbor tagname outputfile

    • eg scripts/create_tarball /full/path/to/arbor v0.5.1 ~/arbor-v0.5.1-full.tar.gz

  7. Download output of wheel action associated to this release commit and extract (verify the wheels and source targz is in /dist)

    • Of course, the above action must have passed the tests successfully.

  8. Update spack/ The checksum of the targz is the sha256sum.

  9. Start a new release on Zenodo, this allocated a DOI, but you don’t have to finish it right away. Add new Zenodo badge/link to docs/README.

  10. Create Github Release:

    • Go to GH tags and click “…” and “Create release”

    • Categorize/edit Github’s autogenerated release notes (alternatively go through merged PRs to come up with a changelog).

    • add tarball to release, created in previous step.

  11. Update Zenodo with authors and changelog created in previous step and submit.

Post Release

  1. Make a new PR setting VERSION to the next with a trailing -dev. E.g. if you just release 3.14, change VERSION to 3.15-dev

    • Include changes such as to spack/, CITATIONS, doc/index.rst in postrel PR. Copy Zenodo BibTex export to CITATIONS.

  2. Update spack package / Ebrains Lab / Opensourcebrain

  3. Announce on our website

  4. Announce on HBP newsletter, HBP Twitter/socials

  5. [AUTOMATED] Add tagged version of docs on ReadTheDocs

  6. HBP internal admin

  7. FZJ admin