Apple has published the full list of restrictions that they are placing on devices, which you should look at before deciding to make any big purchases. As with most software updates, some features are only available on some phones, meaning that you won’t get the full experience without purchasing the latest hardware. Two big pieces: Siri is still only available on the iPhone 4S and iPad 3, and Flyover for Maps is only available on the iPhone 4S and iPad 2 or later.

[Source: 9to5 Mac]