Exchange Team has released Cumulative Update 1 for Exchange Server 2013 RTM.
Few points to note for all Exchange admins who are used to the Rollup Update (RU) model.
- CU1 is the minimum version of Exchange 2013 required for on-premises coexistence with supported legacy Exchange versions. The final build number for CU1 is 15.0.620.29.
- Cumulative Updates in 2013 are like service packs in earlier versions, in that they are full builds, around 1.5GB
- You can install a version of CU (say CU 1) straight without installing 2013 RTM.
- Similar to service pack installation, the CU model will not preserve web.config, registry changes or other custom configuration applied to servers.
- In the unlikely event installing a CU fails and is unrecoverable, re-installation of the server will be necessary.
- Some CU may require an AD schema update, like CU 1.
- A CU for 2013 will be released every quarter.
- Servers in a DAG & CAS array should have the same CU level. Having different versions during the upgrade phase is supported though.
- After you install this CU, you cannot uninstall the CU to revert to an earlier version of Exchange 2013. If you uninstall this CU, Exchange 2013 is removed from the server.
Download 2013 Cumulative Update 1 from here
You have to restart the server after you apply this cumulative update (CU) package.