There's no change to the appearance of the up/down voting arrows on answers with the Android app at the moment. This means that whe you return to a question there's no way of seeing which answers you've already upvoted (or not)
For example, I have voted on one of these answers, can anyone tell me which one, or if it was up or down?
(This is on a Samsung Galaxy Nexus running stock Android 4.3 in case this is something theme related, and I did pick up the latest Stack app update about an hour ago - this is present in both the latest version, and the one before it)
Update:
Have done some more testing on this, and it seems that vote indicators do change colour properly on questions (they change to a reddish-pink background) but not on answers.
When I vote on an answer using the app the background circle briefly flashes red/pink and then goes back to the normal unhighlighted background colour after a fraction of a second, this seems to suggest that this is a bug rather than deliberate behaviour. Have confirmed this on SuperUser and Android.se.