The official Facebook app for Windows Phone 8.1 has a new update in the Windows Store. There's no indication of any new features, so it's likely that it contains just bug fixes.
The change log just shows that the new version number for the app is 18.104.22.168. If you do notice anything major that has been included in this Facebook update, please give us a shout out in the comments.
Thanks to everyone for the tips!