Hi
So far I was very happy with Nethserver, moving from 7+ years of using SME Server.
I updated 5 Servers yesterday about an hour BEFORE the warning went out.
OK, I could revert two running as KVM VMs on Proxmox.
My own Server and 2 others didn’t have the revert option, either due to Hardware, not VM or too much data loss.
I do know the yum history and undo option from SME, but that didn’t work in the simplest case of mine…
I’m a bit worried about the two servers I rebooted. They now have the read-only filesystem. ;-(
-> I’ve fixed this according to the Error after update recreating AD instructions, this works so far. Samba is still not working.
In my opinion, the not-rebooted servers have the greatest chance of recovery.
I do have backups, but what happens after fresh install, restore? Nethserver installs the missing packages but does it update?
Let’s hope the Red-Hatters have a solution soon… 
Nethserver is a good server, i’d like to use it further…
Cheers from Switzerland!
Andy