Exchange 2013 CU5 (Cumulative Update 5) was released on May 27th 2014 and is the first major update after Exchange 2013 Service Pack 1 (CU4). For convenience you can use the following link to download CU5, the latest version of Exchange.
Key issues resolved in Exchange 2013 Cumulative Update 5:
- CU5 includes the transport integration fixes that were included in the post-SP1 update “KB2938053” that may plague the integration of third party products with the Exchange Transport Service, for example antivirus, fax, archiving, etc.
- CU5 contains fixes that help Offline Address Book generation and distribution efficiency in environments where multiple OAB arbitration mailboxes exist. This fix will not impact most customers, as only large environments will likely have multiple OAB arbitration mailboxes, in these environments a complete OAB download will occur after CU5 is installed so this update should be planned accordingly.
Things to know before you install Exchange 2013 CU5:
- CU5 requires AD Schema and Configuration Upgrade.
- CU5 can be installed on top of any prior release of Exchange 2013, and new installs can install using CU5 media.
- Microsoft recommends setting powershell script execution to unrestricted prior to installing Exchange 2013 CU5
- The entire Offline Address Book (OAB) may be downloaded for each user
Here is an easy step by step guide to upgrade an existing Exchange 2013 environment to Exchange 2013 CU5.
If you are installing Exchange 2013 for the first time, here is where you need to begin for a new install of Exchange 2013 (CU5).