High Quality Content by WIKIPEDIA articles! Mozilla Firefox 4 is a version of the Firefox web browser, released on March 22, 2011. The first beta was made available on July 6, 2010; Release Candidate 2 (a base for the final version) was released on March 18, 2011. It was codenamed Tumucumaque, and has been confirmed as Firefox`s last large release cycle. The Mozilla team planned smaller and quicker releases following other browser vendors. The primary goals for this version included improvements in performance, standards support, and user interface.