@ahmed qureshi
Here are some suggestions for you to update your server:
- You cannot update Exchange 2016 to Exchange 2019 directly. You need to create Exchange 2019 coexist with Exchange 2016 first, then migrate mailboxes to Exchange 2019, then uninstall Exchange 2016.
- Exchange 2016 and Exchange 2019 are two different products, so, you still need to purchase license for Exchange 2019.
Before updating, I want to confirm that your DC server is also Windows Server 2012 R2?
Here are update steps for you:
- Update Exchange 2016 at least to CU 11 which supported coexist with Exchange 2019.
- Install Exchange 2019 which hosted on Windows server 2019. (Before this step, make sure the domain function level is at least Windows server 2012 R2)
- Migrate mailboxes and other needed thing such as public folder to Exchange 2019.
- Change DNS record to Exchange 2019 and uninstall Exchange 2016.
- Migrate DC from Windows server 2012 R2 to Windows server 2019. This article may be help for you, for more detailed tutorials, you could confirm with Windows server team.
Here are some other article which will be useful to you during updating:
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.