So I'm on 10549 and I did have the new update for Facebook beta but had to hard reset my phone now it is only downloading the older version. Has anyone found a way to force you mobile to download the windows 10 version?
Other than finding the APPX (which is already pulled from the store, so I doubt anyone can find it) and sideloading it (but you would not get any updates to the app via the store), I don't think there is any other way.
Honestly, the app is not very stable and even managed to crash the whole OS once last night. I guess that's why there are hidden feedback buttons in it.