Windows Server 2012 is officially reaching end of life October 10, 2023 and will no longer receive security updates, non-security updates, bug fixes, technical support, or online technical content updates.

Additionally, the Azure AD Connect v1 is also being retired, likely in anticipation of this EOL for Server 2012.

If you are still running Azure AD Connect v1 on Server 2012, you’ll need to upgrade to Server 2016 to be able to move to Azure AD Connect v2.

As it is advised not to do an in-place upgrade of Server 2012 to Server 2016, here is a comprehensive webpage that goes through the process of migration Azure AD Connect to a new Server.

Migrate Azure AD Connect to new server