I have 2 Lumia 920 phones both from AT&T , i got update for one phone yesterday and another one didn't. it is in same city same location why.
I dont see that in the linke below, software update was for extras + info.
Presumably progressive roll out is by batches of IMEI so must inevitably be cut off points.
Symbian specialist until 31/01/2013 with interests in Maemo & MeeGo but an aversion to Windows!