2.2.1 is the version on sourceforge - much of the talk around here deals with the coming 2.3 (which isn't on sourceforge, because it isn't finished yet).
There are links in the forum to test builds of 2.3, but because it isn't finished it has bugs and other issues, although it does have many new features.
If you want the new features you can download a 2.3 development build, but be aware that it won't be stable and can crash, etc., and is more for bug-testing than playing.
You can also install both 2.2.1 and 2.3 at the same time, I don't think they conflict as long as they are put in separate folders/directories.