Although Mozilla released Firefox version 3.5 not long ago, the team has been showing mockups of future designs. In addition to embracing glass on Windows Vista and 7, future versions will have reorganized interfaces. Previews of Firefox 4.0 suggest that it may have a combined and relocated reload, stop and go buttons, as well as a tab sidebar, tabs on top, and many other UI tweaks -- none of which are set in stone.
Mozilla is now indicating that we may see the launch of Firefox 4.0 next October or November. It has also reportedly updated its roadmap for the release of Firefox 3.6 and 3.7, with the former expected to debut later this year and the latter to arrive in the second quarter of next year. There are also reports that Fennec 1.0 -- the mobile version of Firefox -- will be made available at the same time as Firefox 3.6, and Fennec 2.0 with Firefox 4.0.