iOS 7 is the seventh major release of the iOS mobile operating system designed by Apple Inc as the successor to iOS 6. It was announced at the company's Worldwide Developers Conference (WWDC) on June 10, 2013, and was released on September 18, 2013. iOS 7 includes a redesigned user interface and numerous functionality changes. The design of iOS 7's new elements was led by Jony Ive, Apple's Senior Vice President of Design. As of April 2014, iOS 7 has been installed on 87% of all supported mobile Apple devices. The most recent update, 7.1.1, was released on April 22, 2014.