Release procedure for HPX

Below is a step by step procedure for making an HPX release. We aim to produce two releases per year: one in March-April, and one in September-October.

This is a living document and may not be totally current or accurate. It is an attempt to capture current practices in making an HPX release. Please update it as appropriate.

One way to use this procedure is to print a copy and check off the lines as they are completed to avoid confusion.

  1. Notify developers that a release is imminent.

  2. Make a list of examples and benchmarks that should not go into the release. Build all examples and benchmarks that will go in the release and make sure they build and run as expected.

    • Make sure all examples and benchmarks have example input files, and usage documentation, either in the form of comments or a readme.

  3. Send the list of examples and benchmarks that will be included in the release to and, and ask for feedback. Update the list as necessary.

  4. Write release notes in docs/sphinx/releases/whats_new_$VERSION.rst. Keep adding merged PRs and closed issues to this until just before the release is made. Use tools/ to generate the lists. Add the new release notes to the table of contents in docs/sphinx/releases.rst.

  5. Build the docs, and proof-read them. Update any documentation that may have changed, and correct any typos. Pay special attention to:


      • Update grant information

    • docs/sphinx/releases/whats_new_$VERSION.rst

    • docs/sphinx/about_hpx/people.rst

      • Update collaborators

      • Update grant information

  6. This step does not apply to patch releases. For both APEX and hpxMP:

    • Change the release branch to be the most current release tag available in the APEX/hpxMP git_external section in the main CMakeLists.txt. Please contact the maintainers of the respective packages to generate a new release to synchronize with the HPX release (APEX, hpxMP).

  7. If there have been any commits to the release branch since the last release, create a tag from the old release branch before deleting the old release branch in the next step.

  8. Unprotect the release branch in the github repository settings so that it can be deleted and recreated.

  9. Delete the old release branch, and create a new one by branching a stable point from master. If you are creating a patch release, branch from the release tag for which you want to create a patch release.

    • git push origin --delete release

    • git branch -D release

    • git checkout [stable point in master]

    • git branch release

    • git push origin release

    • git branch --set-upstream-to=origin/release release

  10. Protect the release branch again to disable deleting and force pushes.

  11. Check out the release branch.

  12. Make sure HPX_VERSION_MAJOR/MINOR/SUBMINOR in CMakeLists.txt contain the correct values. Change them if needed.

  13. This step does not apply to patch releases. Remove features which have been deprecated for at least 2 releases. This involves removing build options which enable those features from the main CMakeLists.txt and also deleting all related code and tests from the main source tree.

    The general deprecation policy involves a three-step process we have to go through in order to introduce a breaking change:

    1. First release cycle: add a build option that allows for explicitly disabling any old (now deprecated) code.

    2. Second release cycle: turn this build option OFF by default.

    3. Third release cycle: completely remove the old code.

    The main CMakeLists.txt contains a comment indicating for which version the breaking change was introduced first.

  14. Switch Buildbot over to test the release branch.


    • branch field in c['change_source'] =  GitPoller

  15. Repeat the following steps until satisfied with the release.

    1. Change HPX_VERSION_TAG in CMakeLists.txt to -rcN, where N is the current iteration of this step. Start with -rc1.

    2. Tag and create a pre-release on GitHub using the script tools/ The script requires that you have the STE||AR Group signing key.

    3. This step is not necessary for patch releases. Notify and of the availability of the release candidate. Ask users to test the candidate by checking out the release candidate tag.

    4. Allow at least a week for testing of the release candidate.

      • Use git merge when possible, and fall back to git cherry-pick when needed. For patch releases git cherry-pick is most likely your only choice if there have been significant unrelated changes on master since the previous release.

      • Go back to the first step when enough patches have been added.

      • If there are no more patches, continue to make the final release.

  16. Update any occurrences of the latest stable release to refer to the version about to be released. For example, quickstart.rst contains instructions to check out the latest stable tag. Make sure that refers to the new version.

  17. Add a new entry to the RPM changelog (cmake/packaging/rpm/Changelog.txt) with the new version number and a link to the corresponding changelog.

  18. Change HPX_VERSION_TAG in CMakeLists.txt to an empty string.

  19. Add the release date to the caption of the current “What’s New” section in the docs, and change the value of HPX_VERSION_DATE in CMakeLists.txt.

  20. Tag and create a release on GitHub using the script tools/ The script requires that you have the STE||AR Group signing key.

  21. Update the websites ( and with the following:

    • Download links on the downloads pages. Link to the release on GitHub.

    • Documentation links on the docs page (link to generated documentation on GitHub Pages). Follow the style of previous releases.

    • A new blog post announcing the release, which links to downloads and the “What’s New” section in the documentation (see previous releases for examples).

  22. Merge release branch into master.

  23. Post-release cleanup. Create a new pull request against master with the following changes:

    1. Modify the release procedure if necessary.

    2. Change HPX_VERSION_TAG in CMakeLists.txt back to -trunk.

  24. Switch Buildbot back to test the main branch


    • branch field in c['change_source'] =  GitPoller

  25. Update Vcpkg ( to pull from latest release.

    • Update version number in CONTROL

    • Update tag and SHA512 to that of the new release

  26. Announce the release on,,,,,, the HPX Slack channel, the IRC channel, Sonia Sachs, our list of external collaborators,,, HPC Wire, Inside HPC, Heise Online, and a CCT press release.

  27. Beer and pizza.