Upgrade to 31.2.1 or 31.2.2 will fail if purchased licenses fall short of required licenses. Error like this will be shown in Controller shell CLI only - "show upgrade status detail filter pre_check_status"
Avi 31.2.x and later
Trial licenses will not be counted as valid licenses for upgrade in 31.2.x release and later
Add sufficient licenses to continue with SEG upgrade
Upgrade checklist has documentation note - https://techdocs.broadcom.com/us/en/vmware-security-load-balancing/avi-load-balancer/avi-load-balancer/31-2/vmware-avi-load-balancer-release-notes/checklist-for-upgrade-to-31-2-x.html