I'm in the process of migrating from a single server 2007 exchange environment to a multi server 2013 environment. I'm at the point where I want to move a small group of users to the 2013 serves to do some testing. The only issue holding that back is anyone on the 2007 server cannot view free/busy information of a user on the 2013 servers. This does work when a 2013 tries to lookup a 2007 users free/busy information.
Anyone have any idea why that would be?