If you are using SideFX as the license server then you don't need to go through the upgrade process as the license entitlements in your account will have been automatically upgraded.

You will need to only upgrade the licenses if you have installed them directly to the computer.

To install your license upgrades

1. Go to your account drop-down menu in the top right corner of the License Administrator.
2. Select the Login option. Use the email and password for your SideFX license account.
3. Under the same drop-down, select Entitlements. Any upgrades available for the computer will be listed.
4. Press the "Select All" button and press Install. Or, you can manually select which licenses to upgrade by changing the quantity box from 0 to the same value as the Quantity Allowed column associated with the installed license.
5. Once upgraded, the licenses should be at version 21.0.

Log into your SideFX account and select Entitlements

Upgrades to the existing installed licenses should be listed. Press Install.

Licenses should now be upgraded