CU install in hybrid environment

Question

Hello,
if I want to install(upgrade)Exchange to latest CU via GUI
in hybrid environment is this procedure valid
https://learn.microsoft.com/en-us/exchange/plan-and-deploy/install-cumulative-updates?view=exchserver-2019
or there is something that I need to pay attention when I install latest CU in hybrid environment?
e.g. something like this https://learn.microsoft.com/en-US/exchange/troubleshoot/administration/error-when-running-setup-prepareschema
Thank you

Answer 1

I would run each step separately as a rule. That way its easy to see step completing and running PrepareAD needs to be run separately to ensure the perms changes are made in the forest and lets you verify that each step updated the AD forest

https://learn.microsoft.com/en-us/exchange/plan-and-deploy/prepare-ad-and-domains?view=exchserver-2019

Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareSchema  

Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareAD   

Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareDomain  

Then follow that doc to upgrade: https://learn.microsoft.com/en-us/exchange/plan-and-deploy/install-cumulative-updates?view=exchserver-2019

If you do not have any mailboxes on prem, you really dont need to put into maint mode unless you are using a load balancer that checks that

Once the latest CU is applied, install the latest critical security patch

Answer 2

Hi @fsdg ,
Agree with what Andy said. And in the link you provided, you can refer to the "Best Practices" section.

In addition, you also need to make sure that you have installed all the prerequisites required for Exchange, especially the .NET Framework. The .NET Framework version required by different CU of Exchange server is different, please make sure you have installed the correct version.
For more information: Exchange Server prerequisites and Microsoft .NET Framework

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