iOS

iOS is a mobile operating system designed by Apple for the iPhone and iPod Touch. iOS 1 was released on June 29, 2007. iOS runs on every model of iPhone, iPad, and iPod Touch. Note: iOS does not run on classic iPods.

For an in-depth look at iOS, you can visit the Wikipedia article here: https://en.wikipedia.org/wiki/IOS

To get info on the current version of iOS, you can visit Apple's website here: https://www.apple.com/ios/