The latest Universal release is: 3.2.
You can not upgrade 2.12 via .pup file to 3.x. directly (as the architecture has changed).
The recomended procedure is : Backup , Install fresh version of 3.x., then restore from the 2.12. backup.
From the migration guide:
"You can upgrade to PGP Universal Server 3.2.0 from these versions:
PGP Universal Server 2.12 SP4
To upgrade to PGP Universal Server 3.2 from 2.12 SP4, you must back up your data, do a fresh install, and restore your backed up data. If you are running a version of PGP Universal Server older than 2.12 SP4, you must upgrade to version 2.12 SP4 and then upgrade to PGP Universal Server 3.2.0."
Full details can be found here:
http://www.symantec.com/docs/DOC4565
If you need to migrate a 2.12 cluster I highly recomend this guides:
http://www.symantec.com/docs/TECH149849
http://www.symantec.com/docs/TECH149935