Mozilla has made available a preview of the upcoming FireFox 3.5 web browser for developer testing and community feedback. The 800,000+ users of Firefox 3.5 Beta 4 will be receiving an update to a "Firefox 3.5 Preview" release in order to assist Mozilla's team with further testing and feedback. This update contains many fixes for stability bugs, correctness fixes for the browser's JavaScript engine, and improvements to the built in support for open Ogg based video and audio playback. While this release has not yet completed the testing required to be declared a release candidate, it is considered stable for daily browsing.

Firefox 3.5 Beta users should be receiving this update automatically within the next 24 hours. To get the update immediately, select "Check for Updates" in the "Help" menu.

The Firefox 3.5 Release Candidate is expected to be available in the next 1-2 weeks. Users who would like to become beta testers for Firefox 3.5 and subsequent updates should install the latest available beta and install any offered updates.