This is the human-readable firmware version string for the T2S controller, the central controller module in this power system referenced elsewhere as an alarm source, distinct from the numeric tsiModuleSoftwareVersion reported per power module. For fleet firmware audits at the controller level specifically, the T2S controller's own firmware can be upgraded independently of the individual power modules it manages. An admin verifying a controller-level firmware rollout completed would poll this string across sites to confirm they've all picked up the new controller version, separate from checking each site's individual module firmware.