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 latecomer in the United States. In most cases, the carrier charges extra for tethering an iPhone. Before the SDK was released, third parties were permitted to design "Web Apps" that would run through Safari. Unsigned native applications are also available for "jailbroken" phones. The ability to install native applications onto the iPhone outside of the App Store is not supported by Apple, the stated reason being that such native applications could be broken by any software update, but Apple has stated it will not design software updates specifically to break native applications other than those that perform SIM unlocking. ,