Hi,

I've got this old network that I'm migrating from. This old network has
NT4, Exchange 5.5, and BES 3.6. We've got an AD network that is there is a full trust between 2 networks. We are in process of moving from old network to new AD network and exchange 2003. I've got Exchange 2003 setup. Users login into AD but access their mailboxes in old network (exchange 5.5). The BES 3.6 is pointed to exchange 5.5 server. While I'm planning to move mailboxes from old Exchange 5.5 to Exchange 2003, how can I setup BES to be on both exchange servers. I am not planning to this in one day. It will take 1 week. However I've got 70 BB out there and need to have BES available for both users on Exchange 5.5 and Exchange 2003. Is this possible?

Thanks

If you're in Exchange mixed mode with the 5.5 and the 2003 server in the same Exchange Org, you'll be fine. We were in the same predicament as you a few years back when Exchange2003 went RTM. We had both 5.5 and 2003 users on the same BES 3.6 server. As the old saying goes, "It was transparent to the users".

and if different exchange orgs?

Would you need to upgrade the cdo.dll or anything to make sure that calanders and stuff worked?