Since we havn't yet decided the next version number (the milestone says 1.39/2.0) one way to avoid forgetting, but still allow this to be merged soon is to create another PR with milestone 1.39/2.0 which points to these doxycomments and says "Update to new version when its decided what it will be".
I don't know how to do that. / I am not able to add milestones to PRs.
I used 1.39. It's the number in the current config, so whenever that's updated, the other instances can be grepped.