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 4 supports up to iOS 7, released in September 2013. Due to the relatively aged hardware of the iPhone 4, certain features available on newer iPhone models are not available on the device; as of iOS 7, they include Siri, 3D maps and turn-by-turn navigation, AirDrop, AirPlay mirroring, live camera filters, panorama mode and certain visual effects introduced by iOS 7, such as the blurring of translucent interface elements, the parallax effect on the home screen, and live wallpapers. While still subject to the same limitations, iOS 7.1 did bring some slight performance improvements to the operating system on the iPhone