Mozilla has released the next version of Firefox on June 21, 2011 for desktop and mobile. Firefox 5 includes these updates and new features:

• 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
• Fixed several stability issues
• Fixed several security issues

See the release notes for more details. Firefox 5.0 replaces Firefox 4.0.1 which as now reached end of life support. Next release will be in about 8-weeks with Firefox 6 on August 16th.