http://www.informationweek.com/story/showArticle.jhtml?articleID=196603046
Firefox 3.0, which is currently scheduled for release before the
end of 2007, will be the first Mozilla browser to drop support for
Windows 95, 98, and Millennium, as well as for Mac OS X 10.2 and
earlier.
For those interested in the development of Firefox 3, you can
take a look here.