Perhaps most noticeable is that Exchange Server 2016 CU7 now enforces a Forest Functional Level (and therefore a Domain Functional Level) of Server 2008R2. This change had been announced some time ago, but now it is enforced.
The list of documented fixes in Exchange Server 2016 CU7 is small, but one of the fixes is an annoyance (a warning that can’t be eliminated) associated with UseDatabaseQuotaDefaults when using Set-Mailbox. I’m glad to see it fixed!
Exchange Server 2016 CU7 and Exchange Server 2013 CU18 share another fix which can cause a corrupted email attachment if the attachment is exactly a certain size.
Exchange Server 2013 CU18 also includes various Daylight Savings Time updates for countries all over the world.
Please remember a few things:
You should always test in a lab first.
Your installation of a CU may fail or take significantly longer if you don’t disable anti-virus and anti-malware software before the installation.
If you have a large number of servers, you should probably drain and place each server in maintenance mode before applying the CU (and then return them to operational mode after!).
I generally find that things go more smoothly if you reboot your server “very first thing”.
Not every CU may contain changes to the Active Directory Schema, or to RBAC roles, or many other things. But life can often be made simpler by doing a PrepareSchema and a PrepareAllDomains before executing the upgrade. On my first server to be upgraded, my normal process is this:
setup /IAcceptExchangeServerLicenseTerms /PrepareSchema
setup /IAcceptExchangeServerLicenseTerms /PrepareAllDomains
setup /IAcceptExchangeServerLicenseTerms /m:upgrade
Use an elevated cmd.exe session, not a PowerShell session. (PowerShell searches the path differently than cmd.exe – PowerShell will find the setup.exe in $exbin instead of the setup.exe in the current folder.)
After the upgrade, you should again reboot. Then re-enable your anti-virus and anti-malware. Finally, place the server back in operational mode.
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