IPhone 4S announced iPhone 5s and iPhone 5c. This was unusual for Apple as an upper case 'S' had been used since the introduction of the iPhone 3GS in 2009. On September 9, 2014, the iPhone 4S was officially discontinued following the reveal of the iPhone 6 and the iPhone 6 Plus. However, 4S production did continue for developing markets until February 17, 2016. On June 13, 2016, following the release of iOS 10, Apple dropped support on the iPhone 4S, making iOS 9.3.5 the last version available for the device. The runs iOS, Apple's mobile operating system. The user interface of
IPhone (1st generation) added these features. iPhone OS 2 was released on July 11, 2008, around the same time as the release of the iPhone 3G, and introduced third-party applications, Microsoft Exchange support, push e-mail, and other enhancements. iPhone OS 3 was released on June 17, 2009, and introduced copy and paste functionality, Spotlight search for the home screen, and new features for the YouTube app. iPhone OS 3 was available for the original iPhone as well as the iPhone 3G. However, not all features of iPhone OS 3 were supported on the original iPhone. iPhone OS 3.1.3 was the last version of