Signal started marking their releases as "pre-release" on Github: 
Reason why those are not showing up as latest on Zapstore.
We used to fetch pre-releases, at that time a Termux pre-release screwed up lots of setups.
Pulling pre-releases then needs to be evaluated on a per-project basis, this is hard.
GitHub
Releases · signalapp/Signal-Android
A private messenger for Android. Contribute to signalapp/Signal-Android development by creating an account on GitHub.
