The browser's mobile version is now available to 15 million more phones, Mozilla says.
BlackBerry 10 and Windows Phone 8 will also be taking part in the smartphone battle
Mozilla on Friday backtracked from a decision to suspend all work on a 64-bit version of Firefox for Windows, acknowledging that user criticism had changed its mind.
Users can now keep their existing Firefox windows open when they launch a new private window.
A little more than a year after Mozilla debuted a customized version of Firefox starring Microsoft's Bing search engine, the open-source developer on Tuesday shipped another Microsoft tie-in, Firefox with MSN