Very good point!
Aside from the subcapacity use-case, see this note on our support extension for the 9.2 BigFix agent on HP-UX at BigFix v9.2 agent: support extension for HP-UX operating system
(The short version is, we continue to support the 9.2 HP-UX agent as much as possible, but need to upgrade the BigFix Platform (Server, Relays, etc.) to a current-supported BigFix version. 9.2 HP-UX agent can communicate to a 9.5 or 10.0 BigFix Server deployment)