Upgrade 12.1.11 to 12.1.6

Hello,

We have a virtual Windows 2003 server with SEPM 12.1.

Now we want to install SEPM 12.1.6 on a new virtual Windows 2008 R2 server.

What is the best practice for this?

Move sepm from the old server to the new server. Wait till all the clients have moved away from the old one?

After that upgrade to 12.1.6?

Henry