Tag Archives: CU12

H1 2022 Cumulative Update Exchange 2019 (CU12)

Last week, on April 20, Microsoft released Cumulative Update 12 for Exchange 2019 and Cumulative Update 23 for Exchange 2016.

It took Microsoft six month for the Cumulative Update, that’s because Microsoft is changing from a quarterly release cycle to a bi-annual release cycle. As a result, this will the Cumulative Update of the first half of 2022, so H1 2022 Cumulative Update.

This is only true for Exchange 2019 as there will be no new Cumulative Updates for Exchange 2016 anymore. Exchange 2016 has entered extended support, so Microsoft will deliver Security Updates when needed, but not more CUs. Mainstream support for Exchange 2019 will end on January 9, 2024 and extended support for Exchange 2019 will end on October 14, 2025. This is the same date as for Exchange 2016. What will happen then is still unknown….

Exchange 2019 CU12 now has support for Windows 2022 (finally). Support for Windows 2022 is only true for Exchange 2019 CU12, Exchange 2016 is only supported on Windows 2016.

When it comes to Active Directory, only Exchange 2019 CU12 supports Windows 2022 Domain Controllers. Exchange 2016 and Exchange 2013 do not support Windows 2022 Domain Controllers (despite earlier communication from Microsoft). For more information regarding supportability check the Exchange Supportability Matrix.

One of the new features of Windows 2022 is support for TLS 1.3 and several of my clients have a requirement for this. Unfortunately, Exchange 2019 still does not support TLS 1.3 and support for TLS 1.3 is expected by the end of this year.

With the new Cumulative Update comes a change in (free) licensing. Previously, there was a free license for the ‘hybrid server’ but this was Exchange 2016. Now with Exchange 2016 in extended support and no more CUs for Exchange 2016, the free hybrid license is available for Exchange 2019!

A lot of noise regarding the “remove the last Exchange server” in your organization. When you have all mailboxes in Exchange Online and you have Azure AD Connect running, you need to have one Exchange server, just for management purposes. This is no longer required with Exchange 2019 CU12. You can install the management tools for CU12 and get rid of the Exchange server. Be aware that you must NOT UNINSTALL the Exchange server, but clean up the hybrid configuration using PowerShell, shutdown the Exchange server and run the CleanupActiveDirectoryEMT.ps1 script (released with Exchange 2019 CU12).

Are there reasons to not do this? Yes, think about SMTP relay from on-premises to Exchange Online, or RBAC on-premises (not available with only the Management Tools on-premises), or maybe an offloading possibility when needed. Oh, and if you are not good with PowerShell, be aware that this is a PowerShell only solution. If you are addicted to the Exchange Admin Center, leave the Exchange server running 😉

But nevertheless, it’s good that Microsoft finally heard this feedback and offers a solution for the last Exchange server when all mailboxes are in Exchange Online.

A couple of remarks:

  • Be aware that Microsoft only supports the two latest CUs, i.e. Exchange 2019 CU11/CU12 and Exchange 2016 CU22/CU23.
  • There are no schema changes in these Cumulative Updates, but there are changes in the configuration, so you need to run setup with the /PrepareAD switch.
  • When running a Database Availability Group, do not forget to put the Exchange servers in maintenance mode.
  • As always, test the new CUs in your test environment before installing in your production environment.

More information and downloads:

Exchange versionKB ArticleDownload
Exchange 2019 CU12KB5011156https://www.microsoft.com/en-us/download/details.aspx?id=104131
Exchange 2016 CU23KB5011155https://www.microsoft.com/en-us/download/details.aspx?id=104132
Exchange 2016 CU23 language packshttps://www.microsoft.com/en-us/download/details.aspx?id=104130