There is a known issue that occurs when upgrading the ProxyAV OS from one feature release to another where the license is not applied after the upgrade. For example, after upgrading from 3.2.x.x to 3.3.x.x or from 3.3.x.x to 3.4.x.x, when viewing the license section of the ProxyAV management console, no license is shown.
Performing a soft reboot resolves the issue. Since this issue is only known to affect firmware upgrades from one feature release to another (example: 188.8.131.52 to 184.108.40.206), you should not expect this to happen when upgrading within the same feature release (example: 220.127.116.11 to 18.104.22.168).
To reboot the ProxyAV, access the management console of the unit and go to Utilities>Soft Reboot.