[img]http://t1.gstatic.com/images?q=tbn:ANd9GcRDqhIsygH3qL39hKMkl72Vus-vNYD_UKCwivMccle-lgUQ3bAtgKUWv0gx[/img]

With the recent Facebook update available on BB10 OS, Facebook synchronisation with blackberry hub has been discontinued. What this means is that there will no longer be
instant notifications from Facebook on your BB10 device.
You can now only access your
Facebook page via the browser or you manually add Facebook application to your phone from settings (accounts) to make it
work.
First it was deadline for WhatsApp, now is Facebook though I know very well they are both owned by the same person.Why are
they trying so hard to neglect Blackberry in the scheme of things...only time will tell.

NOTE
If you want to continue enjoying Facebook on BlackBerry 10 OS, do not update your pplication until the last week of March 2017 since old versions of the application will stop working on 31st of March 2017. This may affect blackberry 7 OS as well though I haven't confirmed it.

Source: http://www.loadedportal.com/forum2_theme_111267097.xhtml?tema=302