I postponed all I could to migrate ISA, but looks like I will have to do it right now and I'm wondering how. Basically in my WAN I have to main hub offices, on each of those office I have: - 4 arrays with 2 servers each, plus 1 CSS in office 1 and a backup CSS on office 2. My main question is, can I migrate the CSSs to 2006 and keep the array members on 2004 to start migrating gradually? If not, the only option is to build a new CSS and start migrating the arrays one by one? Al the servers are Windows 2003 EE with SP1 and all the updates, and ISA 2004 SP1 with updates. Thanks guys Regards Diego R. Pietruszka