I think this is going to be the most advance warning I've given about an upgrade in the past 8 months at least:

Tomorrow night, I'll be upgrading the forum to 4.1.0. This is another big one, and probably the last for a while. The forum will be offline briefly. When it comes back, things will be broken. I'll fix the most obvious and worst errors right away, and make you wait until Saturday for the rest.