Upgrading windows 2008R2 to 2019

Question

Hi,

I have a primary and a secondary domain controllers running Windows server 2008R2
I'm planning to upgrade my primary to Windows server 2019, now do I need to demote the secondary before the upgrade?

Thank you

Answer 1

No, you don't.

The two prerequisites to introducing the first 2019 or 2022 domain controller are that domain functional level needs to be 2008 or higher and older sysvol FRS replication needs to have been migrated to DFSR
https://techcommunity.microsoft.com/t5/Storage-at-Microsoft/Streamlined-Migration-of-FRS-to-DFSR-SYSVOL/ba-p/425405

I'd use dcdiag / repadmin tools to verify health correcting all errors found before starting any operations. Then stand up the new 2019 or 2022, patch it fully, license it, join existing domain, add active directory domain services, promote it also making it a GC (recommended), transfer FSMO roles over (optional), transfer pdc emulator role (optional), use dcdiag / repadmin tools to again verify health, when all is good you can decommission / demote old one.

--please don't forget to upvote and Accept as answer if the reply is helpful--

Answer 2

Ok, once the upgrade is done, is it better to upgrade the secondary to match the primary server version (2019) ?

Thank you