It was expected that Apple will announce the new iPhones in the second week of September for a while. Now, Apple has sent across the formal invites to the international media confirming that new iPhones are on the way. On September 9th, 2015 in San Francisco Apple is expected to announce the new iPhone 6s a and iPhone 6s Plus. It is expected that the iPhones will carry the same design as that of the current iPhone 6 and 6 Plus though there will be incremental changes.
One of the changes that have been pretty much in the story for happening is the incorporation of Force Touch, which Apple has already done on its Apple Watch and the new Macbook Airs. The new phones will also bring an upgraded camera module which is expected to take the iPhones back to the summit as far as camera on smartphone are concerned. Given that the venue of the event is Bill Graham Civic Auditorium which houses over 7,000 people, it is expected that Apple would have more to the event than just the new iPhones.
One guess would be that both iOS 9 and El Capitan would be made official at the event and be available to download at the end of the event. The other guess is that Apple could bring the much awaited, new Apple TVs as well as perhaps the iPad Pro, a big 12 inch iPad that has been in rumors for a while. Whatever it is, we shall find out at 10 AM PST on September 9th, 2015.