Please note: Firefox 3.5 Beta 4 is a public preview release intended  
for developer testing and community feedback. It includes many new  
features as well as improvements to performance, web compatibility,  
and speed. We recommend that you read the release notes and known  
issues before installing this beta.

Firefox 3.5 (formerly known as Firefox 3.1) Beta 4 is now available  
for download. This milestone is focused on testing the core  
functionality provided by many new features and changes to the  
platform scheduled for Firefox 3.5. Ongoing planning for Firefox 3.1  
can be followed at the Firefox 3.5 Planning Center, as well as in  
mozilla.dev.planning and on irc.mozilla.org in #shiretoko.

New features and changes in this milestone that require feedback  
include:

        • This beta is now available in 70 languages - get your local version.
        • Improved tools for controlling your private data, including a  
Private Browsing Mode.
        • Better performance and stability with the new TraceMonkey  
JavaScript engine.
        • The ability to provide Location Aware Browsing using web standards  
for geolocation.
        • Support for native JSON, and web worker threads.
        • Improvements to the Gecko layout engine, including speculative  
parsing for faster content rendering.
        • Support for new web technologies such as: HTML5 <video> and <audio>  
elements, downloadable fonts and other new CSS properties, JavaScript  
query selectors, HTML5 offline data storage for applications, and SVG  
transforms.
Testers can download Firefox 3.5 Beta 4 builds for Windows, Mac OS X,  
and Linux in 64 different languages:

http://www.mozilla.com/firefox/all-beta.html

Developers should also read the Firefox 3.5 for Developers article on  
the Mozilla Developer Center:

http://developer.mozilla.org/en/Firefox_3.5_for_developers

Note: Please do not link directly to the download site. Instead we  
strongly encourage you to link to this Firefox 3.5 Beta 4 milestone  
announcement so that everyone will know what this milestone is, what  
they should expect, and who should be downloading to participate in  
testing at this stage of development.