BlackBerry suggests that users go to the appropriate BlackBerry World listing of the Facebook app (found on the sourcelink) where they can download the update. The latter turns BlackBerry's native Facebook app into a link sending you to the web-based version of the site. On the BlackBerry support page the company writes, "Those wishing to continue using Facebook are encouraged to move to the web-based experience which will provide the most feature rich alternative."
After the update, BlackBerry Hub integration will no longer be available on Facebook, and "BlackBerry 10 smartphones will no longer have the ability to share items like pictures and videos directly to Facebook using the Share icon."
"This is an important update which allows BlackBerry users to continue to access Facebook using a browser based interface. In addition to the updates listed below, there are some non-user facing changes that are mandated by Facebook. It is strongly recommended that users update to this version, as older versions of Facebook will stop working on March 31, 2016."-BlackBerry App World
Why is this happening? According to BlackBerry, the private API used on the native Facebook app for iOS and Android is not available for general use, and is not being offered to BlackBerry.
