There have been reports from users that their BBM is asking them to do an upgrade to 2.5 as shown in the image below:

This isn’t for BBM5, but we assume that RIM is at least updating their servers in preparation for its official release. Many users received errors when trying to install the upgrade, as it was indicating that their OS was not supported, and only older versions (4.0 & 4.1) were.
Thus far from the leaked version of BBM5 we know that the official release should have the following:
  • The possibility of adding to the BBM contacts SMS – chat will be possible to carry out the BBM, except that the same chat will take place via SMS
  • Create a group – chat with many people, sending images to entire groups, shared calendar, tasks and events for group
  • QRC Barcode reader
  • Ability to set an avatar that’s visible to all 
  • Increased maximum size of attachments – pictures and notes to 6MB
  • Sending friends your location – with the possibility to receive their location
  • Wireless backup of contacts on the RIM servers 
Hopefully RIM will keep all of these great features and add even more!