Mozilla Releases Firefox 4 With Speed Enhancements and New Look - MacRumors
Skip to Content

Mozilla Releases Firefox 4 With Speed Enhancements and New Look


Mozilla today announced the official release of Firefox 4, the latest version of the organization's popular Internet browser, for Mac OS X, Windows, and Linux. With support for over 80 languages, Firefox 4 brings speed enhancements as well as a sleek new user interface, increased customizability, and new security and privacy features.

Firefox 4 is the fastest Firefox yet. With dramatic speed and performance advancements across the board, Firefox is between two and six times faster than previous releases. Major enhancements to the JavaScript engine make everything from startup time to page load speed to graphics and JavaScript performance screaming fast in Firefox.

The latest version of Firefox introduces a sleek new look that lets Web content take center stage. With features like App Tabs and Panorama, Firefox makes it easier and more efficient to navigate the Web. Firefox delivers industry-leading privacy and security features like Do Not Track and Content Security Policy to give users control over their personal data and protect them online.

Firefox 4.0 is of course a free download, with the Mac version requiring a minimum of Mac OS X 10.5 Leopard.

Popular Stories

iphone duo

Apple Announces Foldable 'iPhone Duo'

Wednesday September 9, 2026 10:56 am PDT by
Apple today announced the "iPhone Duo," a new kind of iPhone featuring two screens and a foldable inner display. The two halves of the iPhone Duo connect into a single continuous frame with the same aspect ratio across both displays, and Apple said the transition between open and closed is designed to feel fluid. When fully open, Apple says it is the thinnest iPhone ever made, with an...
Surprise and Shine Live Coverage Article

Apple Event Live Blog: iPhone Duo, iPhone 18 Pro, and More Expected

Wednesday September 9, 2026 9:10 am PDT by
Apple's "Surprise and Shine" event kicks off today at 10:00 a.m. Pacific Time, where we're expecting to see the foldable iPhone Duo, the iPhone 18 Pro and Pro Max, Apple Watch Series 12 and Ultra 4 models, new AirPods 5 earphones, and perhaps some other announcements. Apple is providing a live video stream on its website, on YouTube, and in the company's TV app across various platforms. We...
apple surprise and shine event

Apple Event Today: iPhone 18 Pro and iPhone Duo Cheat Sheet

Tuesday September 8, 2026 10:24 am PDT by
Apple's biggest event of the year is almost here, and all eyes are on Cupertino. With the first foldable iPhone expected to headline Apple's "Surprise and Shine" event on Wednesday, September 9, at 10:00 a.m. Pacific Time, the rumor mill has been running full throttle, fuelled by the biggest single design change in the life of the iPhone. To get you up to speed, here's a quick reference...

Top Rated Comments

202 months ago
By their support of WebM, FireFox is dead to me.
How does the fact that FireFox supporting WebM impact you negatively in slightest?

What I assume you actually meant was: By them not supporting H264, FireFox is dead to me.. You can still play H264 encoded media via a Quicktime plug-in.

As FireFox is an open source project, Mozilla choose not to ship it with H264 due to it being a patent encumbered codec. People who should be worried about the fact that FireFox supports WebM are Apple. With both FireFox and Google's Chrome supporting WebM, it may become the de facto standard for web video, this would be bad for Apple as they have backed H264.
Score: 1 Votes (Like | Disagree)