you will need a minimum of 6.5.2 (altho' I would be more inclined to go for 6.5.4 as a minimum - but that obviously depends on your current master version).
Thank you for your reply Andy. I'm running Netbackup Master and Media server version 6.5.4.
Went to Fileconnect and downloaded NetBackup_6.5.4_Windows2008_X64.exe
Running client install on the core server gives me the following error: The Veritas NetBackup Client install was interrupted before it could be completed.
Ok. Tried the silent install script. It starts, and since it is a silent script, it does not give me any more feedback. But running a connect from the Master server indicates that the client is not installed.