Agree, Device Switch Wizard is the easiest way. The only things that won't transfer over properly are any themes and apps that are OS dependent, because you are going from a 4.5 OS to a higher version.
After the wizard completes, you may need to go into Options, Advanced Options, Applications and manually delete the themes and apps that don't work properly in the new OS since there is no reason to have them installed and taking up memory.
works quite well for Contacts and Calendar stuff. BBM can be backed up remotely if you have a 5.0 version and restored from that or media card backup. So, you have more than one option for this. Enjoy!
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