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 3GS standards in the countries the 3GS was released. After the release of the iPhone 4S, the 3GS was still offered for free on contract until November 2011, when AT&T raised the price to 59 cents with no explanation. The 99¢ price was only available with a two-year contract on AT&T in the United States and a three-year contract on Telus, Rogers, Bell and Fido Solutions in Canada. This was a departure from Apple's previous trends, in which only two phones were sold. On September 9, 2009, Apple launched an updated model of the iPhone 3GS that patched a segment overflow