Right now, we don’t have something that automatic, but it is a good idea for something that we should implement. They way it works now is that any APK newer than the Current Version Code: set in the fdroid metadata file is something like beta. Users will not automatically get those updates, but they are available for manually updating by going to DAVdroid’s page in the fdroid client, and selecting the version to install.
You can also set up your own nightly builds repo, we do that for guardianproject apps: https://dev.guardianproject.info/debug Those are debug builds signed by a debug key, and are not recommended for real use, only testing. But that process is fully automated, with a new build for each new commit.
There won’t be alpha/beta releases that often. Also, users won’t add a custom repository, so I guess we will just increase the version code and set the release tag to “-betaXXX”. Are the keywords “-alphaXXX” and “-rcXX” covered, too?
I think it makes sense for us implement something that sets the Current Version Code entirely based on git release tags (e.g. with a message and/or a signature). We just need to figure out the best pattern to use. I suppose we could also provide a field to set the specific regexp that defines a beta release versus a full release for that app.