Shoutbox

So far there have been about three different prerelease builds of the new version. The first was a leaked beta or pre-beta (I can't remember), the second was an officially released public beta, and the latest build is the RC1 or Release Candidate 1.

Personally, I wouldn't use the new version just yet unless I really wanted to. I would use the current stable version (8.5), although if you really want to check it out, you can get the latest RC here:

http://download.live.com/messenger