I don't know about booking tickets via the Android DL app, but I just recently updated the app on my phone and have been running into endless problems. The most significant being that 90% of the time the app will get stuck on 'loading information' and never come back from la-la land. I forced a stop of the app more time than I can count, and I've even gone as far as re-installing it twice.

My point is that the app is particularly buggy as of late, so I wouldn't count on it doing anything more than occasionally showing you flight status. Don't get me wrong, I love the app when it works. I prefer the mobile boarding pass over paper, the way it displays itineraries is great, and I adore the upgrade stand-by list. I just think this latest version is not to be depended on.