Is it possible to backup Oracle database 10g Enterprise edition release 10.2.0.5 using latest version of NetBackup?
We are currently using the legacy NetBackup 7.7.3 to backup our Oracle database but we are not sure if we will be able to upgrade our legacy NetBackup to latest version and still be able to backup our legacy Oracle database.
actually even NetBackup 7.7.3 is not officially supported with Oracle 10.x versions. It may work (and it is working as you indicated) but was not tested by vendor.
Generally, you can operate higher versions on Master/Media Servers with older versions on clients (10.x Master is a supported combination with 7.7.3 clients) and cover legacy db support in this way. But as said, even 7.7.3 is too new for Oracle 10g.
All this info is available here: https://www.veritas.com/support/en_US/article.100040093