Well. Update from last RC/PR from dec 2018 went fine.
Only thing I noticed is that some icons seem to be missing or at least not being loaded by SysAdm Client / tray menu as well as SysAdm itself.
Haven’t tested any more than this superficial use.
(Did run the update command again from within the update-BE (= release BE) and to my surprise it ran the update all over again - without downloading the packages anew, of course - but the resulting BE showed the same problem. So I went back to the first update-BE and deleted the second one.
[Edit]: Forgot to add that now that because of the second update try the first update-BE had it’s additional, “manual” reboot the update command results in “everything is up-to-date”…[/Edit])