The Mozilla Foundation today released Firefox 5.0 for iOS devices. In the characteristics of the new versionThis includes improvements in performance and battery life.
New application supports more search engines, comes with a new menu, option to recover old tabs, and a home button. 
You can download the new version from the Apple App Store (link at the end of the post).
The Mozilla Foundation does not usually report exact Firefox usage numbers, although it has reported that “half billion people all over the world" use it program browsing.
Firefox for iOS devices has been released as public preview in September 2015 and as a stable version in November 2015.
The Firefox 5.0 version brings significant improvements in performance and battery life. The Firefox technician for iOS devices Tyler Lacroix reported that he personally saw a decrease of 40 percent in CPU usage and a reduction of up to 30 percent of memory usage with this latest version of Firefox.
