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 the iPhone employs A-GPS operated by the United States. Since the iPhone 4S generation the device also supports the GLONASS global positioning system, which is operated by Russia. The iPhone 6S and 6S Plus, introduced in 2015, feature "force-touch" displays which allows the screen to recognize how hard it is being pressed using pressure sensitive multi-touch technology. All subsequent iPhones with the exception of the iPhone SE and iPhone XR have this feature. An example of how this technology will be used is lightly pressing the screen to preview a photograph and pressing down to take it. iPhones feature a