I have Exchange 2007, and noticed that I have more than a dozen user mailboxes are enabled for Unified Messaging. The only problem is that the UM servers were decommissioned about 3 years ago! So, I can't disable the UM feature on the mailbox via the GUI. I really need to do this so that I can migrate their mailboxes to O365, but as long as the UM feature is enabled and there is a UM address, I can't migrate.
I know I can export the mailbox to a PST, delete the mailbox, and recreate it (been there, done that on a few user mailboxes already)....but I'd really rather not have to go to that kind of trouble if at all possible. I'm hoping for an Exchange Management Shell command or something like that instead.