We are migrating our Exchange Infrastructure from 2003 to 2010 and our Communications Infrastructure from Live Communications Server 2005 to Lync 2010, in a phased approach.
We would like to start our phased approach with installing Exchange 2010 in a Co-Existing Environment and moving some mailboxes over to the 2010 Server.
I'd like to know if this will cause any danger to our Communications Server 2005 setup. We will not be running Unified Messaging and we are not using the availability status in Outlook at the moment, but IM functionality will still need to be available while we are phasing over to Exchange 2010.
Once Exchange 2010 has been implemented successfully and we have moved all the mailboxes accross, we will start with the co-existence of Communications Server 2005 - 2007 and then to Lync 2010.
So in short..... Will IM still be available on Communications server 2005 after installing an exchange 2010 server to co-exist in a current 2003 environment?
The Schema and Forest is at the 2003 level.