Official Facebook Beta for Windows 10 Mobile has received a significant update today. The update brings a much-desired feature that Windows 10 Mobile users have been waiting for. As you can see in the above screenshot the update app adds Contact and Calendar sync settings.
So, you can now sync you contacts across Facebook and People app as has always been possible with the Facebook app developed by Microsoft. Similarly one can now sync Calendar across Facebook Beta and Outlook Mail and calendar apps.
With this update the app has also become smoother but launch time is still on the slower side. Sync works really fast and it is recommended to have this app on Phone Memory for best results.