Windows Neptune build 5111

Neptune build 5.50.5111 is the only leaked build of Microsoft Neptune. It is also known as Microsoft Neptune Developer Release, even though in several places such as winver, it calls itself Windows 2000. The exact compile date is not known, but it is rumored to be compiled in the middle of December 1999. It was sent to developers on the 27th. Other builds might exist, but aren't and will never be leaked.