Need to move around 1500 SEP clients with version 11.0.6 to newly installed 12.1 SEPM server.

Hi All,

Currently we are running two SEPM servers with version 11.0.6.  We can called these servers as A & server B.

We are planning to install new windows 2008 R2 server & configured SEPM v12.1. We can called as server C.

Server A & B having around 1500 SEP clients running with version 11.0.6.

I need correct & easiest steps to move these clients to newly configured SEPM  v12.1 with all existing configuration .

Thanks in advance!