A few new maps. And I'm just busy letting the bots play the maps for a day at a time to stress test the server, and anyone is welcome to join in at any time to mess with the bots.
All older maps will work with 3.99 and you don't need all of the other installs to work. One zip (or installer, when I get around to making an installer or get help with making one) for 3.99, overwrite a couple of maps from previous versions if you have it installed, or bring in maps from the map paks which I'll make public on my site.