Upgraded Symantec Backup Exec 2010 R3 to 2012 SP4 over the weekend.

Objective:
1. Upgrade a CASO and 5 MMS servers from Backup Exec 2010 R3 to Backup Exec 2012 SP4
2. Make sure all the backup jobs are working and the old jobs are restorable.
3. Record the process for future references.
http://www.symantec.com/connect/videos/upgrading-be-2010-r3-be-2012

Result:
I was able to successfully upgrade my Symantec Backup Exec environment from 2010 R3 to 2012 SP4