The new software comes installed in two new iPhones _ the 5C and the 5S _ that Apple will begin selling Friday. The older 4, 4S and 5 iPhone models and the iPad2 can be upgraded to iOS 7 for free.
The iOS 7 is the most radical change to Apple's operating system software for mobile devices since its 2007 debut. It offers a new look to icons along with new features such as a Control Center for easy access to frequently used settings and apps.
Many of the changes are cosmetic. The three-dimensional icons that mimic real-world counterparts _ such as a magazine rack for the Newsstand app _ have been replaced by larger, two-dimensional icons sporting abstract designs and pastel colors. Apple also extended that new look to many of its apps.
The biggest functional change is the use of swipes instead of taps to access key functions. Users can already swipe up from the bottom right side of the screen to quickly access the camera when the phone is in the lock screen.
As for the new phones, there are several key differences from the iPhone 5. The 5S, which costs $100 more than the iPhone 5C, has a faster chip, a fingerprint sensor and a better camera.
Both new models are compatible with a greater range of 4G LTE frequency bands.
That means the phone is more likely to work with higher speeds wherever users go. However, there are more than 40 cellular bands worldwide, the bulk for LTE, so a version bought in one country might not work for high speeds everywhere around the world.
The IPhone 5S starts at $199 with two-year service contract, or $649 without a contract. The iPhone 5C, which is mostly the same as the iPhone 5 it replaces, starts at $99 with two-year service contract, or $549 without a contract.
Initially, they're available in the U.S., Australia, Canada, China, France, Germany, Hong Kong, Japan, Puerto Rico, Singapore and the United Kingdom.
Apple is discontinuing last year's iPhone 5, but will still offer the 2011 edition, the iPhone 4S. That's now free with a two-year agreement.