Earlier today Apple announced that it would be hosting a media event where they will most likely announce the iPhone 5s, iPhone 5c, iOS 7 and possibly an updated iPod Touch.
Based on previous years we guess that iOS 7 will be released to the public on 18 September 2013. This update will be available worldwide.
The Golden Master of iOS 7 should be released to developers immediately after the event.
iOS 7 includes a complete design of iOS with great features like: Control Centre, new look multitasking, Airdrop, and many more.