On April 2, 2013, Microsoft release Cumulative Update 1 for Exchange Server 2013.  For details about this update visit Description of Cumulative Update 1 for Exchange Server 2013.

The RTM version of Exchange 2013 is Version 15.0 (Build 516.32).  This CU will update the system to Version 15.0 (Build 620.29).

Install Exchange 2013 Cumulative Update 1

    1. Download the Exchange 2013 Cumulative Update 1
    2. Run the executable and extract the files.
    3. Right-click setup.exe and Run as Administrator
    4. On the User Account Control page click Yes.
    5. If your Exchange servers have access to the internet setup will check for new updates. Click Next.
    6. In my install no updates were found. Click Next.
    7. Setup will begin copying files.
    8. Once files have been copied setup will initialize.
    9. On the Update page click Next to install the update.
    10. On the License Agreement page select I accept the terms in the license agreement.
    11. On the Readiness Checks page, verify that there are no errors and click Install.
    12. Depending on the roles installed on the server there will be multiples steps to go through for the update.  In my environment it looks like 18 steps.  This can take a long time.
    13. On the Setup Completed window, you can check the box to Launch ECP and then click Finish.
    14. Once ECP launches, navigate to the servers page and you will see that your server version is now Version 15.0 (Build 620.29).