Firefox 3.1 Beta 3 Available

Mozilla has announced Firefox 3.1 beta 3 is out for user testing. Firefox 3.1 brings new feature including high-perfomance TraceMonkey JavaScript runtime, support for the HTML5 video element, and also rendering effects like support for using SVG filters on HTML.Source: Ars Technica
As this is a beta version it is most likely that some (if not all) of your add-ons may not be compatible with this newest version of firefox.
If you want to download it,