Firefox 3.1!

Firefox 3.1 Beta Release Notes 

This is the third development milestone and first beta release of Firefox 3.1, the upcoming version of the Firefox web browser. Please read below for more information.

Firefox 3.1 Beta 1 is the third development milestone and first beta release of Firefox 3.1, the upcoming version of the Firefox web browser. While the release is stable, it is intended for Web developers and members of our testing community for early evaluation and feedback. Users of the latest released version of Firefox should not expect their add-ons to work properly with this beta.

Check out what’s new, the known issues and frequently asked questions about the latest version of Firefox. As always, you’re encouraged to tell us what you think, either using this feedback form or by filing a bug in Bugzilla.

Firefox 3.1 Beta 1 is based on the Gecko 1.9.1 rendering platform, which has been under development for the past 6 months. Gecko 1.9.1 is an incremental release on the previous version with significant changes to improve web compatibility, performance, and ease of use:
Web standards improvements in the Gecko layout engine
Added support for CSS 2.1 and CSS 3 properties
A new tab-switching shortcut that shows previews of the tab you're switching to
Improved control over the Smart Location Bar using special characters to restrict your search
Support for new web technologies such as the 
Mozilla provides Firefox 3.1 Beta 1 for Windows, Linux, and Mac OS X in a variety of languages. You can get the latest version of Firefox 3.1 Beta 1 here. For builds for other systems and languages not provided by Mozilla.org, see the Contributed Builds section at the end of this document.

Please note that installing Firefox 3.1 Beta 1 will overwrite your existing installation of Firefox. You won’t lose any of your bookmarks or browsing history, but some of your extensions and other add-ons might not work until updates for them are made available.

(website :  http://www.mozilla.com/en-US/firefox/3.1b1/releasenotes/ )