Wirelessly posted (BlackBerry9630/5.0.0.591 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/105)
I was notified in person by a UA Gate Agent. Of course, I was already on the plane so that made sense.
If you booked prior to October 12 you need to call in to have them add you to the UDU list. If it is a new booking no need to worry about that. If you have the UA PNR you can check the reservation on the UA site and see if it is listed as queued for the upgrade.