As of today (March 2021) we still have more than two years to use Windows Server 2012 R2 server. Smart thing to do would be to plan your exit strategy and make sure your services are on supported Windows Server version when support for WS 2012 R2 is near its end. I use WS 2012 R2 for years now on daily basis, and it has been great and rock solid software, but it’s time to move on :(