Exchange Team has released service pack 3 for 2010 deployments.
The service pack was scheduled for Q1 of 2013 and the wait is over now! Exchange 2010 SP3 allows 2010 servers to coexist with Exchange 2013 CU1, which is also scheduled to be released in Q1 2013.
2010 SP3 brings update to AD & database schema. As a result, when mailbox servers are upgraded to Exchange 2010 SP3, the databases are upgraded to the SP3 version of the database schema. After a database has been updated to the SP3 schema, it can’t be mounted on a pre-SP3 mailbox server.
A DAG member that is running an older version of Exchange 2010 can move its active databases to a DAG member running a newer version of 2010, but can’t do the reverse. After a DAG member has been upgraded to SP3, its active database copies can’t be moved to another DAG member that’s running pre-SP3 code.
The Exchange Team blog says that SP3 can be run on Windows Server 2012.
But, the release notes says that it can only run on Windows 2008 SP2 or 2008 R2 OS.
One of them has to be wrong
Download Exchange 2010 SP3 here.