Hi,
Check your mailbox, you might have received upgrade notification.
Notification email contains serial number to download 12.1 product and all other related information.
If you have not received any notification then check on https://fileconnect.symanatec.com.
If you are not able to see SEP 12.1 on your fileconnect account then you will have to call License department.
License department will verify your details and will guide on same.
Contact number : 18003420652 to connect license department follow the IVR.