Firefox 4 DelayedFirefox 4 Delayed

Microsoft Internet Explorer 9 Beta Revealed

Mozilla has delayed the release of Firefox 4 until early next year, saying development of the popular open source browser has taken longer than expected.

Mozilla engineers and contributors to the open source browser had been scrambling to get it ready for a November release. However, despite "strong progress" in development, delays in completing the feature-complete beta 7 version of Firefox, along with the amount of work remaining to prepare the software for release, made it impossible to meet the release date, Mozilla announced Wednesday.

"Completing this work is taking longer than initial estimates indicated as we track down regressions and sources of instability," Mike Beltzner, product manager for Firefox, said in a blog post on Mozilla's developer site. "As part of our commitment to beta users, we will not ship software before it is ready."

Beltzner said Mozilla would continue to release "beta milestones" through the end of December, with a release candidate shipping in early 2011 and the final release close behind.

However, Beltzner said even the latest timetable could change. "Please note that, as always, this schedule is subject to change based on feedback from users and community members."

After years as the innovation leader in browser technology, Mozilla last year found itself unprepared to match Google's aggressive development of Chrome, as well as revitalized development of Safari and Internet Explorer by Apple and Microsoft, respectively. Firefox 4 represents Mozilla's effort to recapture mindshare and continue growing market share, even as browser makers shift attention from the desktop to mobile distribution.

At the end of September, Firefox accounted for nearly 23% of the browser market, while Microsoft's share was nearly 60%, according to Net Applications.