Migrate Roles from Server 2008 R2 to Server 2019
1. Reduce DHCP lease to 2 hours or so
2. Update DHCP Scope/Server options to include backup DNS servers.
Additional Robocopy Info:
Migrate Azure AD Connect: https://practical365.com/identity/migrating-azure-ad-connect-new-server/
Windows Server Migration Tools (this didn't work for us, we were getting VERBOSE: Error 127: Feature Remote Access Service could not be exported.): https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/jj134202(v=ws.11)?redirectedfrom=MSDN
Remote Access and Routing migration: https://www.snel.com/support/how-to-set-up-a-vpn-with-windows-server/
Remote Access and Routing issues: https://social.technet.microsoft.com/Forums/windowsserver/en-US/0270d377-be3a-4b63-82a0-9df076c5e3b3/upgrade-from-2016-to-2019-breaks-dhcp-relay-agent-when-using-rras?forum=ws2019
Issues with DFN namespaces: https://techjourney.net/dfs-namespace-cannot-be-queried-error-remove-delete-orphaned-namespace/