Got to the ground yesterday and for some reason my ticket had updated from the Aresnela game to... Dortmund at home from back in September! I scanned it anyway and it let me in.
The reason I just scanned it & i kind a knew it would work is that the same happended with my Dad last week against Arsenal. His was still on the Leicester game from a few weeks earlier and we just couldn't update it (he's not on Iphone), anyway we turned up, scanned it and it worked & let him in.
Seems as long as you have a valid season ticket, it seems to work no matter what is showing ont he screen (based purly on just 2 examples from 1 Iphone & 1 non Iphone)