Firefox includes tabbed browsing, a spell checker, incremental find, live bookmarking, a download manager, and an integrated search system that uses the user's desired search engine. Install Firefox Extended Support Release. Firefox Extended Support Release (ESR) is an official version of Firefox developed for large organizations like universities and businesses. Firefox ESR does not come with the latest features but it has the latest security and stability fixes. Firefox; where can I download old version of Support Forum. where can I download old version of Firefox (needed for support with some software) 4 replies 9 have this problem views Last reply by djannakhan or your clients are in a corporate environment there is a possibility that Firefox ESR . Sep 23, · Firefox (Beta 3) is a fast, flexible and secure web browser with a mission: to build a better internet and make web browsing better for you. Firefox ESR is intended for groups who deploy and maintain the desktop environment in large organizations such as universities and other schools, county or city governments and slicelive.comegory: Web Browsers.