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)
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.