works great on my Icon running WP8.1 update Lumia Black. (still waiting for Cyan and/or Denim whichever comes first :-( )
the only issue I have is the location widget. when at the home lock screen and I tap the location button it goes to the start screen the goes back to the home lock screen. but if I open another widget (be it the calendar or the stopwatch) then hit the location button it loads the map and finds my location without fail.
other than that it works great!
-HTC Mogul PPC-6700 ->HTC Arrive ->Nokia Lumia 822 ->Nokia Lumia Icon