We're currently running 6.5.2 and about to move to 6.5.5. I'm going to be investigating 7 at the same time. Can anyone estimate for me how much downtime will be required to move to 7.0? We currently have about 4.5 million posts, almost 64,000 users, etc.

I don't think the users will mind reasonable downtime as long as they know roughly how long it will be.

Chuck