For those who use systemd networking (thus NOT NetworkManager or Wicked).
This morning I did a YaST > Online Update. There was a “recommended update” for systemd. Accepting the suggested updates I got a pop-up that explained that due to dependencies it would additionally install systemd-resolved and systemd-networkd and would remove systemd-network. I accepted. I new pop-up informed me that a re-boot was required.
After the reboot I found that the network was not functioning. Some research showed that I had to (as root of course)
The above mentioned bug report is declared to be a duplicate of 1253956 – Failed to install systemd update. but that one handles the fact that originally systend-networkd and systemd-resolved were installed without removing systemd-network they replace. That was apparently resolved but without enabling the new service(s) if needed (i do not even know if it is possible to do that, one has to check if the old service was enabled or not).
Thus I am not sure if the “not enabling new one when old one was enabled” on installation is solved, I will mark this topic as “solved”. After all it can only hit you once per system on an update and it is now documented here to be found by forum visitors.