Adobe Media Flash Server 3.5.1 compatibility

We have Adobe Media Flash Server 3.5.1 on a Windows server 2008 R2 and we want to upgrade to server 2012 R2. I cant find anywhere about compatibility with this version and Windows OS. Does anyone know if this works without issues? If not, do we need a new license key to get a newer version such as 5?  Thanks for any info 🙂

Craig