Want the answers to questions about the iPhone? You'll find questions and answers here.
Can I Update ios7 In My Carrier Unlocked iPhone ?
When iOS 7 is launched, you will be able to upgrade, as iOS 7 will be supported on iPhone 4 and newer. Open Settings > General > Software Update, and you will be able to install it when launched.
iOS updates are launched by Apple and they don't depend on the carrier or device like Android, so iOS 7 will probably be released for all devices at the same time. It will be launched in fall