This read-write 32-byte DisplayString reports the alternate software revision; it's written automatically after a cold boot by the ComController, and if a user later writes a new value here, the ComController fetches a fresh set of alternate images from the boot server even if the release string itself doesn't strictly change. It's the field an admin manages when staging a standby firmware version ahead of an upgrade, distinct from hcxHcxSwRelease which reports what's already active. For example, an operator preparing for a scheduled upgrade would write the target version into hcxHcxAlternateSwRel first, prompting the controller to pull those images from the boot server before the actual cutover.