Originally Posted by
lhrsfo
I have booked UA flights on other ticket stock and upgrade processing with GPUs does not work as well. I don't know if it's changed, but I couldn't apply my GPU until check in.
How long ago? This has been working for a long time IME.
SDC is the other main thing which officially only works on 016 tickets; that was a change a couple years ago; prior to that it worked pretty well on anything.