Upgrading symantec 12.1.671.4971

Hi,

We are using SEPM 12.1.671.4971 server and running 4000 client machines. Now, as sepm 12.1.671.4971 doesn't support windows 2012/8, we are planning to upgrade to the next possible version. Please let us know the steps to be taken for this migration.

Regards,

Anishk