We upgraded from 220.127.116.11 -> 18.104.22.168 -> 2.6.1.06.
After the upgrade, everything worked except the RADIUS authentication. Checking the RADIUS logs, I see "An Access-Request message was received from RADIUS client IP with a Message-Authenticator attribute that is not valid.
I have recreated the shared key and added it back into the vWLAN controller. Same problem.