All our users are on Exchange 2010 and have been migrated for some time now. We started out with Exchange 2003, then migrated to 2007 and now 2010. My concern is this. While looking at a users attributes using ADSIEdit, I noticed that just about all our users have a LegacyExchangeDN that matches our 2003 Admin Group. This is because they were all on 2003 at one time before being migrated to 2010. I still have that 2003 Admin Group and one server in the environment. I keep it there to run a Free/Busy sync app with one of our partners. I plan on eventually removing that final 2003 server in the near future but I am concerned because just about everyones LegacyExchangeDN points to the DN of that Admin Group. Whats going to happen when I decommission that final 2003 server and delete the Admin Group? Will my users experience problems because their LegacyExchangeDN points to a path that is no longer valid?