I am currently on 2012 DFL and FFL. I currently have Server 2012, 2012 R2 and 2016 DCs in my environment. I'm in the process of removing all 2012 and 2012R2 DCs. I have migrated to DFSR and I will be performing the Forrest prep and Domain prep. I know there has been some security updates with 2019. Has anyone seen any gotchas, or things to watch out for, when adding your first server 2019 Domain Controllers?