The panel now carries one wfrac node per unit, polling as well as commanding, so a command can be checked against the unit's own answer rather than assumed. Three things kept a panel from driving the old unit. The seeded commands catch is off by default, which is the usual reason a fresh panel looks dead; AIRCON_COMMANDS=1 arms it at seed time. A unit that is off names no mode, and a flow redelivers every bound port on each run, so that rejected value blocked every command including power-on. And the old firmware serves one connection at a time.