Although you probably still haven’t seen the update notification, there is an update available for the Windows Phone Facebook application. All you need to do is head over to the Marketplace find the Facebook application, open it, refresh the page and the update button should now be visible.
The new version brings support for the new Windows Phone 7.5. Thanks to it you’ll be able to pin elements like the News Feed and Messages as tiles in the Start Menu. There are also some new items added for the Toast & Tile Notification which will supposedly present you with a detailed list of all event notifications.