I used to run 7.2.97 on an old Pi3b (could not upgrade to a newer version due to MongoDB dependencies).
I installed 8.1.127-unraid and restored config (seemed to work fine); using bridge.
However, it was stuck in a forever "Provisioning" / "Offline" loop.
I eventually established that the reason was that it was sending the Inform IP to the Docker IP rather than the LAN IP, i.e.:
172.17.0.6:8880/TCP192.168.88.69:8880
Inform IP was being set using 172.17.0.6 rather than 192.168.88.69 .
Manually updating the Inform IP (host) in the new Unifi controller to 192.168.88.69 fixed the issue.
This is how docker works in conjunction with the automatic discovery of the controller and is unfixable, and is why manual override is provided by unifi.
I used to run 7.2.97 on an old Pi3b (could not upgrade to a newer version due to MongoDB dependencies). I installed 8.1.127-unraid and restored config (seemed to work fine); using bridge. However, it was stuck in a forever "Provisioning" / "Offline" loop. I eventually established that the reason was that it was sending the Inform IP to the Docker IP rather than the LAN IP, i.e.: 172.17.0.6:8880/TCP192.168.88.69:8880 Inform IP was being set using 172.17.0.6 rather than 192.168.88.69 . Manually updating the Inform IP (host) in the new Unifi controller to 192.168.88.69 fixed the issue.