... I literally
just moved everything except the most recent to a new location so as to allow for upgrade to 6.5.4.
These directories are used to provide the ability to 'roll-back' to previous versions. As an example the following is an extract from
DOCUMENTATION: Due to design changes in the Veritas NetBackup (tm) 6.0 Client Pack installer, the /u...
"...
If it is not desired to maintain the ability to roll back to a previous pack, these ... directories may be removed. Do not remove or archive the
pack.history or
pack.summary files, however. These serve as a record for what packs have been installed on the system.
..."
HTH