Forum Discussion
Exchange Server 2016 / 2019 coexistence CU update
CUs are cumulative, so they contain updates from all previous updates, so you can go from CU14 to CU19 in one install. There may be a schema update required, and you can check this by reviewing all the CU's and checking.
Don't forget to install the latest security update after the CU is installed
Thanks for your reply!
So the AD Schema should already be up to date because of the Exchange server 2019 CU 14 which is the latest CU.
When we want to upgrade the Exchange server 2016 from CU 19 to CU 23, there are AD schema updates required. But I am wondering how this will react because of the schema already on the latest version.
Will it just skip the schema updates?
Microsoft don't support two different versions of Exchange in the same organisation for extended periods (only supported while migrating to the new version), so I'd recommend decommissioning the Exchange 2016 servers and building new Exchange 2019 servers.