Firefox 3.0 is yet to be finalized, but Mozilla is already looking ahead to the upcoming versions of the open source browser. Planning to release the successor of Firefox 2.0 by the end of June 2008, Mozilla managed to get a sneak preview into the evolution of version 3.0 but also of the whole product. In this context, Mike Shroepfer, Mozilla Vice President of Technology, revealed that following the availability of Firefox 3.0 by mid-2008, Firefox will not jump directly to version 4.0. An interim variant 3.1 is in fact planned to drop virtually on the heels of 3.0.

Essentially, Firefox 3.1 will bring to the table functionality and capabilities that were scrapped from v30. "There were a number of features that we held back from Firefox 3 because they weren't quite ready - but they were nearly complete. These include things like XHR, native JSON DOM bindings, ongoing performance tuning, awesomebar++, better system integration, etc.," Shroepfer stated.

What Mozilla is promising with Firefox 3.1 is even more performance compared to version 3.0, a milestone of the open source browser that is already getting high praises for its speed boost. Firefox 3.0 already includes the Awesome Bar, also referred to as the Smart Location Bar in the Release Candidate 1 build dropped at the end of the past week. And it seems that Mozilla is looking to take the feature one step further by completely melting together the search box and location field in a move designed to revolutionize user navigation.

But most importantly, Firefox 3.1 will be a version focused on developers. And in this regard, Mozilla looks to embrace the HTML 5 specification, delivering support for . Version 3.1 will also be tweaked to play even better with masups and web-based applications through support for cross-site XMLHttpRequests.

"This along with the overall quality of Gecko 1.9 as a basis for mobile and the desire to get new platform features out to web developers sooner has lead to us want to do a second release of Firefox this year. This release would be date-driven and targeted at the end of 2008. Any features not ready in time will move to the next major release," Shroepfer added.

With Firefox 3.1 planned for availability by the end of 2008, Mozilla is currently scoping Firefox 4.0, the next iteration of the open source browser after 3.0 and 3.1 for next year. "Firefox 4 will incorporate some of the more aggressive platform improvements in Mozilla2. It is far too early to set a shipping date but an initial target would be sometime in late 2009," Shroepfer promised.

For the time being, Firefox 2.0 and Firefox 3.0 Release Candidate 1 (RC1) for Windows are available for download here.
Firefox 3.0 Release Candidate 1 (RC1) for Linux is here.
Firefox 3.0 Release Candidate 1 (RC1) for Mac is here.