<p>Cumulative Update 1 (CU1) for Exchange 2013 is now available from Microsoft, enabling organizations to go forward with on-premises deployments that mix Exchange Server 2013 with earlier Exchange Server versions.</p><p>CU1 also adds hotfixes dating back to the release of Exchange 2013, along with some new features.</p><p>With the new CU1 in place, Exchange 2013 can coexist with Exchange 2010 Service Pack 3 or Exchange 2007 Service Pack 3 with Update Rollup 10. It also allows Exchange 2013 to work with a mix of those two legacy servers. Organizations trying to get Exchange 2013 working with Exchange 2003 are out of luck as it's not supported at all by Microsoft. A table showing the possible coexistence scenarios can be found here.</p><p>CU1 reflects Microsoft's new quarterly release cadence that it announced in February. IT pros now get full builds of products with these cumulative update releases, so they are going to be a bit fatter. This release, called "build 15.00.0620.029," is a 1.3 GB download and can be accessed here.</p><p><a href="http://rcpmag.com/articles/2013/04/02/exchange-2013-cu1-released.aspx">Keep reading...</a></p>