You may be wondering if your iOS device will support iOS 7. Apple typically limits new releases of their mobile operating system to hardware that can run the firmware smoothly. Some features might be limited even if your device does run iOS 7.
For those asking, "What devices will support iOS 7?" here's a complete list of supported devices:
iPhone 4
iPhone 4S
iPhone 5
iPad 2
iPad 3
iPad 4
iPad mini
iPod touch 5G