For a brief overview of the changes I can think of offhand:
- The military works very differently now. It is more complex, and a bit hard to get a handle on, but now that I understand how it works, I think I'm getting it to do well for me.
- There are, as Telrunya says, burrows you can designate to force dwarves to stick to certain areas (though they can travel between them). I use this to keep my smelters and the haulers dedicated to them on task.
- In .40d, you could order your dwarves to just go inside. Now, you can't: you must designate a burrow that your civilians will remain within, and activate an alert that sets them there. Mine includes everything inside my outer wall.
- There are now hospitals, which, with the fixes in .22, should be pretty much completely functional at last. Any dwarf who gets injured will try to go to the hospital, and dwarves with the various (new) medical labours enabled will (eventually) diagnose and treat them.
- In the latest feature version, .20, Toady added a bunch of new creatures and labours, including bees, and the beekeeping industry to support them, and clay and a pottery and ceramics industry to support it. He also made (some of) your animals require grazing land, and gave you the ability to pasture them. The latest version I've played is .18, so I can't comment on the practical effects of these changes yet.
- Bauxite is no longer the only magma-safe stone; a whole host of different stone types are now magma-safe, thanks to some research and setting the actual melting points of most stones in the game to their RL equivalents.
Some new bugs in the 0.31.x line that, so far as I know, remain, and seem unlikely to be fixed in time for .22:
- Trader caravans don't bring wagons; everything is loaded onto horses and donkeys. This doesn't change what they bring, it just means that it takes them absolutely bloody forever to load back up before they leave, and means you don't have to build 3-tile-wide access to your depot (though it's still a good idea, in case Toady fixes wagons!).
- Nobles appointed by the Baron or Mayor are broken. This means no Dungeon Master. I'm unclear as to what the status is of nobles that belong with the King; stay tuned, though, because I've got a game running that's ready to become the Capital, and should get the King within another year...
And yes, the DF Wiki is an absolutely necessary resource.
