As expected, Apple has released the iOS 7 gold master for developers ahead of its launch on September 18. Developers enrolled in the iOS Developer Program can get their hands on the iOS 7 GM build by logging in to the developers portal using their Apple ID. The iPhone 5, iPhone 4/4S, iPad 2 and later, iPad mini, and the fifth-gen iPod touch all support the iOS 7 gold master.
The GM is released with the purpose of polishing the near-to-final build and removing any major bugs not discovered during the beta phase. It will also give developers a chance to test their applications for over a week before the operating system debuts publicly.
To install, just download the package from the download portal and restore your iOS device, just as you would during a full restore.
Apple will release the final version of iOS 7 on September 18th, two days before the new iPhone lineup hits stores.