Hello,
Apologies if any of the information below is incorrect but here goes:
When your contract ID and support is registered under the appliance's serial number then you can simply go to 'System Administration --> System Upgrade' and click the 'Upgrade Options...' button.
From there you will see the latest, stable AsyncOS releases. Just download and install.
If you want to try out the FCS (first customer shipment) - or now known as ED (early deployment) releases then you will need to raise a ticket with support (easy to do from the appliance) saying so.
They'll add your serial number to the ED list so that your appliance finds the ED upgrade the next time it checks.
