Debian stretch has chosen an unfortunate intermediate state resp. version of postfixadmin.
Some forms, particulary those for auto reply, are in slightly weird and confusing shape. Furthrermor, both our installations had to switch to the trunk version of vacation.pl.
I decided to switch our installation to the trunk, building on the existing debianization (see this discussion on the postfixadmin mailinglist).
I hope to find the time to eventually adapt postfixadmin's debianization to the SuSE build services (where official rpms seem to be created), but first I chose the approach that's easy and well-known to me:
After creating my own postfixadmin github fork (and extending .gitignore a bit) I created a branch pba2deb.clazzes.org where I adapted debian/* for straight-forward PBA-based deployment to Clazzes.org's debian repository deb.clazzes.org.
Using our packages happens on one's own risk, obviously.
Apt integration snippets
While it would be possible to download the deb manually from the any-postfixadmin-3.1 pool, it's also possible to "apt-connect" our package to a debian stretch system or something close enough (like Devuan ascii, Ubuntu, ...):