upgrade exchange 2019 CU8 to CU10 hybrid

Question

We are looking to upgrade our exchange 2019 CU to CU10

We are a hybrid setup with no on-premise mailboxes, all mailboxes are in o365

I am reading the instructions regarding the schema prep steps.

From what i can deduce i need to run the below

Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareSchema

then

Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareAD /OrganizationName:"<Organization name>"

I have 2 questions regarding the PrepareAD step

1. Is it correct that since we are just upgrading we dont need to specify the /Organization switch?
2. If it is required, where do i find out what the value was during the server install?

And reading the KB, do i need to run this and if so how does the command line look? Is it 2 different commands or a single command in the /PrepareAD step?

Important

If you have a hybrid deployment configured between your on-premises organization and Exchange Online, add the /TenantOrganizationConfig switch to the command.

Answer 1

In Hybrid environment, /TenantOrganizationconfig is mandatory. We can not run /PrepareSchema on its own. This is because we need to provide the /TenantOrganizationConfig but this parameter does not exist with /PrepareSchema.
Since it only exists with /PrepareAD we will use that, and it will automatically run /PrepareSchema if the account has the correct permissions (Schema Admin).
So, you may proceed the following steps for deploying the CU10 in Hybrid environment

1. Get the TenantOrganizationconfig value. Connect Exchange Online through PowerShell and get the file containing the value Get-OrganizationConfig | Export-clixml -Path C:\Tenant.xml
2. After that you run prepare AD using that xml file Setup /PrepareAD /TenantOrganizationconfig:C:\Tenant.xml /IAcceptExchangeServerLicenseTerms
3. Now, you can proceed with the installation by running the setup.exe file in iso - Fine the reference here: install-cumulative-updates