Apple's new iPhone software, iOS 7, is only a day old, but it's already on ~40% of all iOS devices, according to mobile analytics company Mixpanel. To put that in context, Google's latest operating system, Jelly Bean is on 45% of Android devices, and its been out for a year.
Apple takes great pride in its lack of fragmentation. In an interview with Bloomberg Businessweek, CEO Tim Cook talked about carriers like AT&T selling Android phones running an older version of the operating system. By the time consumers exit the AT&T store with a new phone, Cook says, "they're using an operating system that's three or four years old. That would be like me right now having in my pocket iOS 3. I can't imagine it."
Business Insider