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 5S September 2016, replacing it and its A7 processor early meant that Apple "just reduced its long-term chip support window by a year" for iOS. In addition, a new iPhone launch was meant to stimulate demand, as sales of iPhone 6S and 6S Plus had not met expectations since their September 2015 release and the iPhone family was expected to suffer its first ever negative growth quarter in 2016. The iPhone 5S maintains a similar design to the iPhone 5, with a LCD multi-touch Retina display and a screen resolution of 640×1136 at 326 ppi. Its home button has been updated