Mozilla Firefox 5 is a web browser developed by Mozilla Foundation , available for download in full install version for Windows platforms from legacy sources. This version of Firefox was officially released on 2011-06-21 for public access and a brief summary of important updates and change log pertaining to this edition can be read below.

Firefox 5 is released with many performance improvement components like canvas, JavaScript, memory, networking, and HTTP idle connection logic. Certain locales will now see improved spell checking. There are many standard supports have been included like HTML5, XHR, MathML and SMIL. This edition also extends support for CSS Animations.

There are known issues remain unfixed like gmail slow rendering in Windows Platform, Can not use Power PC CPU for Firefox on Mac Platform, and QuickTime video button not functioning in Linux Platforms.