iOS is an operating system that is developed and issued by the American company Apple. The first version of iOS was presented in 2007 and, in contrast to its biggest rivals — Windows and Android — iOS is supported only on Apple devices. The App Store by Apple has a large list of Bitcoin iOS applications created for storing, mining and trading. And besides that, there are some blockchain iOS applications that allow storing documents and photos, playing games, programming, etc. Also, some of these applications convert Bitcoin for iOS, but the system itself is still considering accepting cryptocurrency. Nevertheless, Apple changed its policy several times, as all applications related to Bitcoin for iOS were banned and then available again.