If you actually look at the changes to xscreensaver upstream (as the Debian xscreensaver maintainer did), you will see that most of the changes only mattered fo

If you actually look at the changes to xscreensaver upstream (as the Debian xscreensaver maintainer did), you will see that most of the changes only mattered for iOS users so there was little point updating to the latest version, apart from the security fix, which was backported quickly.