More than two years after the last release, Bay12 Games have unleashed Dwarf Fortress 0.40.01 on the world. From Toady's release announcement:
Here is the world activation release! Lots of processes from world generation — birth, invasions, succession, site foundation, and so on — now operate in the world after play has begun. Getting all of that to work led to a meandering route through various pieces of the game, some of which are described below. Aside from any bugginess, a lot of it will still feel rough and unfinished as things bump around.
Although many of us will be waiting around for extra stability and for our mods and tilesets to support the new version, many more will be sharpening their pickaxes and hoping they can create the next Planepacked.
