Exchange 2016 CU19 Released

Exchange 2016 CU19 has been released to the Microsoft download centre!  Exchange 2016 has a different servicing strategy than Exchange 2007/2010 and utilises Cumulative Updates (CUs) rather than the Rollup Updates (RU/UR) which were used previously.    CUs are a complete installation of Exchange 2016 and can be used to install a fresh server or to update a previously installed one. Exchange 2013 has the same servicing methodology.

This is build 15.01.2176.002 of Exchange 2016 and the update is helpfully named ExchangeServer2016-x64-CU19.iso which allows us to easily identify the update.  Details for the release are contained in KB 4588884.

Exchange 2016  has transitioned out of  mainstream support lifecycle, and is now it the extended support phase of its lifecycle.

Updates Of Particular Note

As always security updates deserve a particular focus. Exchange 2016 CU19 includes the December 2020 security releases.

4593465 Description of the security update for Microsoft Exchange Server 2019 and 2016: December 8, 2020

This update contains AD Schema changes, so please plan accordingly.

OWA download/preview has been updated 4588297 Attachments can't be downloaded or previewed from Outlook Web App

Note that there are some known issues when preparing AD which are discussed in the release KB.  There are additional operations required for multiple domain environments where /PrepareAD needs to be executed manually in the other domains.

This CU still has the Autodiscover EventID 1 error in the Application event log.  See KB 4532190 for details.

Please note  that .NET Framework 4.8 is a requirement.  See this post if installing .NET and the Exchange CU in the same maintenance window.

Details are listed in the Exchange Server prerequisites.  Also note the requirement for Visual C++ Redistributable Package for Visual Studio 2013.

Issues Resolved

• 4588297 Attachments can't be downloaded or previewed from Outlook Web App
• 4583531 Design change about inline images will be forced to download but not open in a new tab of OWA in Exchange Server 2016
• 4583532 ELC MRM archiving fails due to DomainName in AuthServer in Exchange Server 2016
• 4583533 Exchange Server 2016 installation fails with error "The user has insufficient access rights"
• 4583534 Event ID 65535 System.Runtime.Serialization errors in Application log in Exchange Server 2019 or 2016
• 4583535 New-Moverequest, Resume-Moverequest, and Remove-Moverequest not logged in Audit logs in Exchange Server 2016
• 4583536 Set-MailboxFolderPermission is included in Mail Recipient Creation in Exchange Server 2016
• 4583537 Update Korean word breaker in Exchange Server 2016
• 4583538 Microsoft Teams REST calls exceed the default value of maxQueryStringLength in Exchange Server 2016
• 4583539 Non-breaking space is visible in message body in Outlook in Exchange Server 2016
• 4583545 Make DomainName in Authserver a multivalued parameter in Exchange Server 2016
• 4593465 Description of the security update for Microsoft Exchange Server 2019 and 2016: December 8, 2020

Some Items For Consideration

Exchange 2016 follows the same servicing paradigm for Exchange 2013 which was previously discussed on the blog.  The CU package can be used to perform a new installation, or to upgrade an existing Exchange Server 2016 installation to this CU.  Cumulative Updates are well, cumulative.  What else can I say…

Customers with a hybrid Exchange deployment, must keep their on-premises Exchange servers updated to the latest update or the one immediately prior ( N or N-1).

• Test the CU in a lab which is representative of your environment

• Review this post to also factor in AD preparation which is to be done ahead of installing the CU onto the first Exchange server

• Follow your organisation’s change management process, and factor the approval time into your change request

• Provide appropriate notifications as per your process.  This may be to IT teams, or to end users.

• After you install this cumulative update package, you cannot uninstall the cumulative update package to revert to an earlier version of Exchange. If you uninstall this cumulative update package, Exchange is removed from the server.

• Place the server into SCOM maintenance mode prior to installing, confirm the install then take the server out of maintenance mode

• lace the server into Exchange maintenance mode prior to installing, confirm the install then take the server out of maintenance mode

• I personally like to restart prior to installing CUs.  This helps identifies if an issue was due to the CU or happened in this prior restart, and also completes any pending file rename operations.  3rd party AV products are often guilty of this

• Restart the server after installing the CU

• Ensure that all the relevant services are running

• Ensure that event logs are clean, with no errors

• Ensure that you consult with all 3rd party vendors which exist as part of your messaging environment.  This includes archive, backup, mobility and management services.

• Ensure that you do not forget to install this update on management servers, jump servers/workstations and application servers where the management tools were installed for an application.  FIM and 3rd party user provisioning solutions are examples of the latter.

• Ensure that the Windows PowerShell Script Execution Policy is set to “Unrestricted” on the server being upgraded or installed.  See this article on setting PowerShell to Unrestricted..

• Disable file system antivirus prior to installing. Do this through the appropriate console.  Typically this will be a central admin console, not the local machine.

• Verify file system antivirus is actually disabled

• Once server has been restarted, re-enable file system antivirus.

Please enjoy the update responsibly!

What do I mean by that?  Well, you need to ensure that you are fully informed about the caveats with the CU  and are aware of all of the changes that it will make within your environment.  Additionally you will need to test the CU your lab which is representative of your production environment.

Cheers,

Rhoderick