Apple says the iPhone Duo will ship with iOS 27.1 when it launches this October, which gives us a hint at when the first major iOS 27 update will come out. The iPhone Duo will be available on October 23, so iOS 27.1 should be released shortly before that date. Last year, iOS 26.1 didn't come out until November 3, but we're expecting iOS 27.1 about two weeks earlier. iOS 27.1 will include updated app layouts built for the iPhone Duo's dual displays and its new vertical dock.