Question : Problem: Blackberry Enterprise Server - Upgrade Questions

I am currently running BES 4.1.6 on old hardware.  I wish to upgrade to BES 5.0, but also need to migrate to new hardware.  The plan is to run 5.0 on a 2008 virtual server.  All the mobile devices are being upgraded to version 4.5 now, so that won't be part of the project.  The other problem is that I need to migrate the user mailboxes to a new Exchange 2007 server that already exists.  I would like to move the mailboxes as I migrate the Blackberry users from one BES to the other.  Any ideas?  

Answer : Problem: Blackberry Enterprise Server - Upgrade Questions

This may help as well with the migration.  From personal experience, I agree with the statements in this post.  If you only have a few users, >15 or so, it may be a lot easier to just build the new BES server in the VM, and reactiveate the phones manually.  Moving BES to a new system, and upgrading it can be a royal pain.

http://www.experts-exchange.com/Networking/Misc/Q_22996082.html