iOS 7 is set to be rolled out sometime in the mid of September for all the users using an iPhone 4 and above. It is very impressive that Apple’s latest software update will support a device which is almost 3 years old now. That is perhaps one of the best features of the company and why you pay a premium for them, as in the long run, they always seem better value for money. However, not all the devices will be getting all the features of iOS 7. Some of the devices will get a stripped down version of iOS 7 and that is perhaps understood given that they want to maintain an optimum performance even on hardware that might not be on terms with the fast and furious ones of today.
If you are also worried about what your iPhone 4 may miss out when iOS 7 goes out of Beta and rolls out for general public, then Redmondpie have come up with a very impressive chart that pretty much details all the features of iOS 7 and the devices. It clearly states the features some of the devices will not be getting such as there would be no airdrop for iPad 2 and iPhone 4.
However, do not be disheartened and thank your stars that your device would still be getting an iOS 7 update, imagine where the Android devices of three years are and the updates they have received. The grass is definitely greener on this side.