Exchange 2016 CU8 Released

Exchange 2016 CU8 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.

Download Exchange 2016 CU8

This is build 15.01.1415.002 of Exchange 2016 and the update is helpfully named ExchangeServer2016-x64-CU8.iso which allows us to easily identify the update.  Details for the release are contained in KB 4035145.

Exchange 2007 is no longer supported, updates are not provided once a product has exited out of extended support.

Updates Of Particular Note

Update 8-1-2018:  Please note the issue for cross-premises free busy as discussed in KB 4058297.

.NET framework 4.7.1 is now fully supported.    Currently this is an optional item, but will be required with the June 2018 CU.  Plan accordingly!   Customers should test, verify and install CU8 then move to update to .NET 4.7.1 which will be required for the June 2018 CU install.  It will remain optional for the March 2018 CU.

Advanced notification was with the release of CU7 provided so that administrators can proactively plan to update the .NET Framework.  This is similar to the approach with .NET 4.6.2 – Please see Exchange 2013 CU16 and Exchange 2016 CU5 .NET Framework Requirement for more details.

.NET Framework 4.7 is not supported.

CU8 introduces a change in TLS and cryptography settings.  Previous CUs would overwrite a custom configuration.  TLS and cryptography is now configured at install time and future CUs should not overwrite customisations .

Hybrid Modern Authentication (not HAM)  provides users the ability to access on-premises applications using authorisation tokens obtained from Office 365.  These OAuth tokens allow access to authenticate against on-premises Exchange.

If you are in an environment where Exchange 2016 coexists with Exchange 2010, then please also review Exchange 2010 SP3 RU19 as you will need to install that update on Exchange 2010 to resolve a proxy issue.

As per Active Directory Forest Functional Levels for Exchange Server 2016, it was announced that Exchange Server 2016 would enforce a minimum 2008R2 Forest Functional Level requirement for Active Directory.  Cumulative Update 7 for Exchange Server 2016 will now enforce this AD DS requirement.

Issues Resolved

4056329 Can’t access EWS from Outlook/OWA add-ins via makeEwsRequestAsync in Exchange Server 2016 and Exchange Server 2013

4054516 “Your request can’t” error when accessing an archive mailbox via OWA in Exchange Server 2016

4055953 The recipient scope setting doesn’t work for sibling domains in Exchange Server 2016

4055435 No MAPI network interface is found after you install Exchange Server 2016 CU7

4056609 Event ID 4999 and mailbox transport delivery service does not start after you install Exchange Server 2016 CU7

4045655 Description of the security update for Microsoft Exchange: December 12, 2017

4057248 Many Watson reports for StoragePermanentException in Exchange Server 2016

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…

For 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

  • Place 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 KB981474.

  • 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.

  • Note that customised configuration files are overwritten on installation.  Make sure you have any changes fully documented!

  • CU8 does NOT contain new AD Schema updates for your organisation.

While CU8 does not add any new AD Schema changes.  If you are on an out-dated CU currently, then deploying CU8 may contain AD Schema updates for your organisation – please test and plan accordingly!  Whether or not your AD Schema needs to be updated depends upon your initial Exchange 2016 version.  This will dictate if the AD Schema needs to be modified.

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.



Rhoderick Milne [MSFT]

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