Initial impressions: The update was a bit rocky. About an hour after a successful upgrade, my ZD1200 became partially unresponsive (was not responding to WebUI, though it was responding to the APs/APMgr, partly responding to SSH but hangs after attempting to log in).... There was a blinking red light on the unit. Rebooted, and that problem seems to have gone away.
It does appear to fix my connectivity loss on R710 after prolonged connectivity / standby. I've not had to toggle wifi on any of my desktops and usually by now I would. Crossing my fingers that this is resolved 🙂