If you are under a support contract you can upgrade to the latest version at any time.
The server upgrade is usually very quick - you uninstall all of the server components (dont panick !) FD Config, WinClient, Enterprise Manager etc.
Then you install the latest server program. When you launch the FD Config program you should see if pick up the license and all of the settings. The stay behind when you upgrade.
Now install the latest client software on the server.
You may need to upgrade your cabinet in Enterprise manager - right click on it and select upgrade.
Next you will need to deploy the latest client software to your users.
Gotchas ! Make sure the license manager has been updated so it shows you are in support.