@davidep I tested upgrade to 7.6 on a allready installed test-VM with local AD.
Some notes:
Kernel now is 3.10.0-957
Samba DC is 4.8.6
Account: Join is OK
All services expected to run are running
No errors during update.
User create, edit and delete works
(in Cockpit this doesn’t work, because it’s not possible to verify the password, but cockpit itself seems to work)
Webtop: send and receive mail works (internally from one user to another, externally not tested)
Webtop: event create, modify and delete works. A fullday event is not editable after creation with opera browser, but chrome, firefox, edge are working
OpenVPN roadwarrior: works
Fileserver installation fails: package is samba 4.7.1 but libs are installed allready on 4.8.3 (@cr)
Created some firewall objects: CDIR, hosts, ip-range, times and zones and suddenly the machine was unreachable. Reboot and signal-event interface-update didn’t help ether.
Stop shorewall helps. My fault: I created a zone “green” with the internal subnet, but I can’t delete it now. 
Isn’t there a validator to prevent this? OK, deleted the props in networks db, now all works again.
Further tests willbe done.
So long, now I’ll have a 