Exchange 2007 has officially now been dropped by Microsoft today
A great product which was the base for Exchange 2010 and up helping with DAG setups and using powershell , it will be sad to see it go!
This was bundled in with Small Business Server 2008 so if you are using this version you will need to look at migrating your users elseswhere!
What are your migration paths?
1) Upgrade and Migrate to the Cloud e.g. Office 365 (using their FastTrack service if you have a Minimum of 50 Users Seats)
2) Upgrade and migrate your server to Exchange 2013 ( Can only do one jump so no Exchange 2016 ! )