The build string for the latest build we know about is "7077.0.090404-1255," which indicates that it was compiled less than a week ago: April 4, 2009, at 12:55pm. Some of you will realize that this is 20 minutes after the supposed build 7105 was compiled, which is widely rumored to be a milestone build. Microsoft only increments the second digit of the build number if an important point in development has been reached. The software giant is expected to give a new build to testers this month, and a public Release Candidate build is coming in May. More at; http://arstechnica.com/microsoft/news/2009/04/first-screenshots-of-build-windows-7-build-7077-leak.ars
