This trap-only object carries the HRP state the device was in before an HRP state-change event, such as active or standby. Admins reviewing an HRP state-change trap use it to see exactly what the previous state was, providing context for the transition captured in the notification. Seeing a value of 'active' here in a trap tells an admin the device was previously active before transitioning to whatever hwHrpTrapNewState now reports.