I would recommend disabling the Policy Manager on each Gateway, installing the new Policy Manager, migrating the Gateways and pointing each Gateway to the new Policy Manager after they are migrated.
We are currently running 1.04 and i am trying to schedule an upgrade to 2.x. We will be upgrading in-place on existing Windows 2003 SP2 servers, these servers CPU support SS2 feature. My questions are:  1) How long does it take to upgrade 4 gateway machines and one policy manager 2) Can some gateway machines be running Windows 2008 and others Windows 2003 3) What else do i need to think about ?  ps: i did read "esrs pre-install guide"  Thank you
Upgrade process from 1.04 to 2.x