12-24-2012 12:33 AM
When we update our phone's OS, depending on what apps are retored back to the phone, there are times that it comes with stock app versions. Go to your phone's browser and go to http://blackberry.com/bbm or visit App World and download the latest version of BBM.
Please let us know if this resolves your issue. Good luck
12-24-2012 12:36 AM
You don't need to as the download will ask you if you want to replace the existing version.