.0NTumucumaqueMarch 22, 2011New default theme on all platforms, redesigned extension manager and notifications, tabs on top, new Firefox menu on Windows, app tabs, integration with Firefox Sync and Panorama, WebM support, WebGL support, GPU-based hardware acceleration of web content, additional optimization to the TraceMonkey engine called JägerMonkey, improved support for HTML5 and CSS3 features.4.0.1NApril 28, 2011Regular security and stability update.Firefox 55.05.0YJune 21, 2011[29]Added support for CSS Animations; the Do-Not-Track header preference has been moved to increase discoverability; tuned HTTP idle connection logic for increased performance; improved Canvas, JavaScript, memory, and networking performance; improved standards support for HTML5, XHR, MathML, SMIL, and Canvas; improved spell checking for some locales; improved desktop environment integration for Linux users; WebGL content can no longer load cross-domain textures; Background t