Mozilla has released a 64-bit version of Firefox for Windows. Mozilla claims this will improve performance over the 32-bit version for applications and games but lacks support for certain plugins. As reported previously, Mozilla is dropping support for most plugins by late 2016, anyway. Other changes include choice of blocking additional trackers in Private Browsing mode, improved API support for m4v video playback, search suggestions in the address bar, and more. The Android version has also been updated, and includes support for marking items as read/unread in reading list panel, tab audio indicator in tab list, new split pane styling for History panel on tablets in landscape mode, include URL when sharing selected text from web page, and more. You can download either from the link...
Source: http://www.gsmarena.com/firefox_for_windows_gets_64bit_support-news-15559.php