I have an SBS2011 server that is still providing email, file shares and RWW. The project is to get the email into the Exchange Online and migrate the PDC to a Server 2022 VM with a Server 2022 member server for LOB applications. Workstations are still Windows 7. I am not so concerned about the email migration and will likely use a third party tool that will also handle the Outlook profiles on the desktops.
The SBS2011 AD domain has an existing member server running LOB applications. My intention is to migrate the 2008r2 PDC to server 2022 Will the existing 2008r2 LOB member server still run attached to the domain during the migration process. A new member server (vm) will be added after the FSMO roles have been migrated but keeping the LOB server in place until we can do a controlled move will be key.
After researching further I find the document linked below that talks about domain functional levels. It says "Windows Server 2008 R2 functional levels" supports "Windows Server 2022 domain controller operating systems" So do I read that the 2008r2 member server will continue to operate without any problems? As I said it will be replaced as a final phase of the migration by installing a second 2022 virtual member server to run the LOB apps and the old 2008r2 server will be decommissioned. Is it recommended to raise the domain functional level unless for a specific purpose anyway?
https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/active-directory-functional-levels
For a member server on Windows Server 2008 R2 it does not matter what the SBS 2011 is doing. You can even migrate everything of the SBS 2011 and still have the 2008 R2 server connected to your domain because another Domain Controller will then be in place for Directory Services. During the migration you need to upgrade Forest and Domain Functional level 2008 R2 at least but for the 2008 R2 server that is not an issue.