Breaking Changes

This document describes QMK's Breaking Change process. A Breaking Change is any change which modifies how QMK behaves in a way that in incompatible or potentially dangerous. We limit these changes so that users can have confidence that updating their QMK tree will not break their keymaps.

The breaking change period is when we will merge PR's that change QMK in dangerous or unexpected ways. There is a built-in period of testing so we are confident that any problems caused are rare or unable to be predicted.

What has been included in past Breaking Changes?

When is the next Breaking Change?

The next Breaking Change is scheduled for May 30, 2020.

Important Dates

  • 2020 Feb 29 - future is created. It will be rebased weekly.

  • 2020 May 2 - future closed to new PR's.

  • 2020 May 2 - Call for testers.

  • 2020 May 28 - master is locked, no PR's merged.

  • 2020 May 30 - Merge future to master.

  • 2020 May 30 - master is unlocked. PR's can be merged again.

What changes will be included?

To see a list of breaking change candidates you can look at the breaking_change label. New changes might be added between now and when future is closed, and a PR with that label applied is not guaranteed to be merged.

If you want your breaking change to be included in this round you need to create a PR with the breaking_change label and have it accepted before future closes. After future closes no new breaking changes will be accepted.

Criteria for acceptance:

  • PR is complete and ready to merge

  • PR has a ChangeLog


This section documents various processes we use when running the Breaking Changes process.

Rebase future from master

This is run every Friday while future is open.


cd qmk_firmware
git checkout master
git pull --ff-only
git checkout future
git rebase master
git push --force

Creating the future branch

This happens immediately after the previous future branch is merged.

  • qmk_firmware git commands

    • git checkout master

    • git pull --ff-only

    • git checkout -b future

    • Edit readme.md

      • Add a big notice at the top that this is a testing branch.

      • Include a link to this document

    • git commit -m 'Branch point for <DATE> Breaking Change'

    • git tag breakpoint_<YYYY>_<MM>_<DD>

    • git tag <next_version> # Prevent the breakpoint tag from confusing version incrementing

    • git push origin future

    • git push --tags

4 Weeks Before Merge

  • future is now closed to new PR's, only fixes for current PR's may be merged

  • Post call for testers

1 Week Before Merge

2 Days Before Merge

Day Of Merge

  • qmk_firmware git commands

    • git checkout future

    • git pull --ff-only

    • git rebase origin/master

    • Edit readme.md

      • Remove the notes about future

    • Roll up the ChangeLog into one file.

    • git commit -m 'Merge point for <DATE> Breaking Change'

    • git push origin future

  • Github Actions

    • Create a PR for future

    • Make sure travis comes back clean

    • Merge future PR