Apple has done this two ways in the past...
iPhone OS 2, 3, iOS 4
April - preview
June - public release
iOS 5, 6
June - preview at WWDC
Sep/Oct - public release
Rumors are that Apple will release the iPhone 5S sooner, maybe as soon as in June/July compared to Sep/Oct.
iPhone OS 2, 3, iOS 4
April - preview
June - public release
iOS 5, 6
June - preview at WWDC
Sep/Oct - public release
Rumors are that Apple will release the iPhone 5S sooner, maybe as soon as in June/July compared to Sep/Oct.