And it's expected that apple will reduce the price of previous iphone generations: with 100$ less on past year iphones (like iphone 5) and 200$ for past 2 years iphones (iphone 4 and 4s).
Also it's expected that apple will launch the cheaper version of iphone called Iphone 5C on the 10th september 2013 , and the updated version of iphone 5 called Iphone 5S with more perfomances and updates like faster CPU, better Camera and the new exclusive update: The FingerPrint Sensor for more security and to unlock the Phone.
And as we know the new generations of iphones will come after some days of launch the official version of IOS 7, that countain many new updates especially in design.
read: the New IOS 7 Beta 5: New Design update and Performances