Symantec NetBackup nbpatch_check
Utility to check and download the latest NetBackup patches from Symantec Support is available here:
 http://entsupport.symantec.com/docs/339570

6.x Release Update Availability Document:
NetBackup Agents/Options are required to be at the same level as the NetBackup client and/or server packages.  For example, a UNIX client running Lotus Notes should be updated with the NetBackup 6.5.3 client package (NB_CLT_6.5.3.tar) and the 6.5.3 Lotus Notes update (NB_LOT_6.5.3.tar).  Occasionally, some Agents/Options are not updated with new code and are not distributed with a release update.  These situations require the Agent/Option to fall back to the latest patch available if it is not available for the current release update.  For example, a UNIX client running Oracle should be updated with the NetBackup 6.5.3 client package (NB_CLT_6.5.3.tar), but since there is no Oracle Agent update for 6.5.3, the 6.5.2 Oracle Agent update (NB_ORA_6.5.2.tar) is to be applied.  

The following TechNote indicates what packages are available for each 6.x Release Update to assist in determining the latest version available:
 http://support.veritas.com/docs/290620

6.5 Release Updates and Hotfix:
6.5.x Release Updates requires 6.5 GA installation media be installed before installation.  For customers in need of 6.5 GA installation media, please click on the following the link:    http://support.veritas.com/docs/308850

The release updates are cumulative and do not require the application of the previous release update.  For example, a customer running 6.5.GA can apply the 6.5.3 release updates directly, there is no need to apply 6.5.1/6.5.2 in order to move to the 6.5.3 level.  

Hotfix installation requires NetBackup to be at the corresponding release update level or the utilization of LiveUpdate.  

6.5.5 - Entire list of NetBackup 6.5.5 Release Update links
 http://entsupport.symantec.com/docs/337041

6.5.4 - Entire list of NetBackup 6.5.4 Release Update links
 http://support.veritas.com/docs/326270

6.5.3 - Entire list of NetBackup 6.5.3 Release Update links
 http://support.veritas.com/docs/315028

6.5.3 Hotfix 1 (6.5.3.1) Entire list of NetBackup 6.5.3 Hotfix 1 Links:

 http://support.veritas.com/docs/319624

6.5.2 - Entire list of NetBackup 6.5.2 and the 6.5.2A Release Update links.
 http://support.veritas.com/docs/303467

6.5.1 - Entire list of NetBackup 6.5.1 Release Update links
 http://support.veritas.com/docs/300874

6.5 GA - For customers in need of 6.5 GA installation media, please click on the following the link:
 http://support.veritas.com/docs/308850

6.0 Release Updates
6.0 MPx Release Updates requires 6.0 GA/6.0 MP4 installation media be installed before installation.  For customers in need of 6.0 GA/6.0 MP4 installation media, please follow the link below:
 http://support.veritas.com/docs/308850

The release updates are cumulative and do not require the application of the previous release update.  For example, a customer running 6.0 GA can apply the 6.0 MP7 release updates directly, there is no need to apply 6.0 MP1-MP6 in order to move to the 6.0 MP7 level.  

Security Update installation requires NetBackup to be at the corresponding release update level.  

6.0 MP7- Entire list of NetBackup 6.0 Maintenance Pack 7 links
 http://support.veritas.com/docs/308875

6.0 MP7 Security Update 1 (6.0 MP7S01) - Entire list of NetBackup 6.0 MP7 Security Update 1 Links

 http://support.veritas.com/docs/319630

6.0 MP6 - Entire list of NetBackup 6.0 Maintenance Pack 6 links
 http://support.veritas.com/docs/300550

Compatibility Lists:

6.x Master Compatibility List -  http://support.veritas.com/docs/303344