We have ZD1100 managing 8 AP's, few are connected on the same LAN as the ZD, and the others are on remote site and reach the ZD via IPSec VPN.
I upgraded the ZD from 9.5.1 to 9.7.1, it seemed to work well and the directly connected AP's upgraded fine to 9.7.1. The problem is that all remote AP's got stuck in the state: "Upgrading firmware" and did not pass this stage (they were still reachable but did not connect any clients).
I did a rollback of ZD to 9.5.1 and all AP's were back online.
The remote AP's has full access to the ZD over the VPN and normally act with no problem. Any idea why the firmware upgrade of remote AP's might fail? Anyone with a similar setup?
There is a mention of "5.1.5 - Resolved an issue with APs being unable to join ZoneDirector due to the default MTU size set on Zone Director running on version 9.6 . (ID ER-929)"
this is my guesswork, you may not have seen this issue in 9.6 however there was something related in 9.6 which got fixed in 9.7.1 however now you may be seeing the manifestation of incorrect fix. again this is my guess nothing for sure.