Mozilla has today made the release of Firefox 4 official. Windows, Mac and Linux versions are available, and in numerous different languages, ranging from mainstays like English, French and Chinese to less commonly-supported languages like Icelandic and Catalan. Only a handful of languages are still limited to v3.6.15, namely Assamese, Georgian, Occitan and Serbian.
Version 4 represents a major overhaul of Firefox designed to keep it on par or ahead of browsers like Chrome or Safari. By default it now places tabs on top, and introduces other interface elements such as “app tabs,” tab groups and the ability to browse and install add-ons in a more closely-integrated system. Like Chrome, Firefox 4 makes it possible to sync bookmarks and other settings with multiple copies of the browser.
Performance is another major emphasis of the upgrade. Start and rendering times are claimed to be dramatically faster than in Firefox 3.6, thanks both to a new JavaScript engine and support for hardware acceleration, GPU, in the form of OpenGL on Macs and Direct 2D and 3D in Windows. If Flash, QuickTime or Silverlight crashes in a tab, Mozilla claims that Firefox itself will continue to run.