Exchange 2013 CU19 has been released to the Microsoft download centre! Exchange 2013 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 2013 and can be used to install a fresh server or to update a previously installed one. Exchange 2013 SP1 was in effect CU4, and CU19 is the fifteenth post SP1 release.
This is build 15.00.1365.001 of Exchange 2013 and the update is helpfully named Exchange2013-x64-cu19.exe. Which is a great improvement over the initial CUs that all had the same file name! Details for the release are contained in KB 4037224.
Whether or not your AD Schema needs to be updated depends upon your initial Exchange 2013 version. This will dictate if the AD Schema needs to be modified. Check the values as noted in this post. There may be additional RBAC definitions, so PrepareAD should be executed prior to installing CU19. If setup detects that PrepareAD is required it should be automatically executed if the account running setup has the necessary permissions. This was an issue first discussed in the MessageCopyForSentAsEnabled post and in Unexpected Exchange AD Object Values.
Exchange 2007 is no longer supported, updates are not provided once a product has exited out of extended support.
Update 21-12-2017 – updated note on .NET support
Updates Of Particular Note
.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 CU19 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 provided with the release of CU18 so that administrators could 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.
CU19 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.
4046316 MAPI over HTTP can't remove client sessions timely if using OAuth and the resource has a master account in Exchange Server 2013
4046205 W3wp high CPU usage in Exchange Server 2013
4046182 Event ID 4999 or 1007 if diagnostics service crashes repeatedly in Exchange Server 2013
4056329 Can't access EWS from Outlook/OWA add-ins via makeEwsRequestAsync in Exchange Server 2016 and Exchange Server 2013
4045655 Description of the security update for Microsoft Exchange: December 12, 2017
Some Items For Consideration
As with previous CUs, this one also follows the new servicing paradigm 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 2013 installation. You do not need to install Cumulative Update 4 or 5 for Exchange Server 2013 when you are installing the latest 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).
After you install this cumulative update package, you cannot uninstall the cumulative update package to revert to an earlier version of Exchange 2013. If you uninstall this cumulative update package, Exchange 2013 is removed from the server.
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
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!
While CU19 does not add any new AD Schema changes. If you are on an out-dated CU currently, then deploying CU19 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 2013 version. This will dictate if the AD Schema needs to be modified. Check the values as noted in this post. Additional RBAC definitions may also be required.
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.