While the last Facebook Beta update brought many new features and new Live Tiles, the latest update has arrived without a changelog. There is nothing mentioned about this new update so possibly it is a minor performance improvement and bug fixes kind of update.
For updating the Facebook Beta, open the app if you have already installed it, then swipe to right, go to settings-> about ->Check for update. In case, you have not installed this Beta yet on your device click the direct link below. You can run both Beta and official app on your device simultaneously.