You often mutually - replace BlackBerry or are going to update your BlackBerry OS? if you are going to do it, you would need to back - up your BBM contacts first, before you will lose all contact BBM friends, colleagues or family. And after you are done backing up your BBM contact if you have a moment to update your BlackBerry or replace with a new one you will stay connected with your BBM contacts after having restored earlier.
Here's how to back up your BBM contacts:
Open / Run your BBM.
Press the menu / BlackBerry logo button on your device.
Select / Click the Options menu.
Scroll down to the Backup Management menu, then click Back Up.
Back-up window will appear with two (2) preferred method of backing up your BBM contacts.
Back up files remotely: If you select this option means that backing up your BBM contacts will be sent to the email integrated with your BBM (Push Email), so this option you can choose if you enable packet BlackBerry (BIS) which supports push email.
Back up files locally: if you select this option means the file results back up your BBM contacts will be stored in your BlackBerry memory (either internal memory or sd memory card)