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
Model year Model year The model year (MY) of a product is a number used worldwide, but with a high level of prominence in North America, to describe approximately when a product was produced, and it usually indicates the coinciding base specification (design revision number) of that product. The model year and the actual calendar year of production rarely coincide. For example, a North American 2015 model year automobile is available during most of the 2015 calendar year, but is usually also available from the third quarter of 2014 because production of the 2015 model began in July or August 2014, continuing