Ever since the preview for Windows Phone 8.1 went out, the Facebook beta app ironically has lagged behind the official ?stable? public version. That means while you could use the Beta app with no issues on 8.1, you were also missing the Social Extensibility framework integration, including access to your Photos Hub, Sharing and more.
Version 8.1.4.25 just went live in the Store, and we can confirm that for 8.1 users, you can now use this instead of the public app and still get those new 8.1 features.*
Full story from the WPCentral blog...