Now, though, the third beta version of iOS 6 has been released to developers, and some are reporting that some of those key features appear to have made their way onto the older device.
iSource reports that VIP Mail will be available on the iPhone 3GS, a feature that allows users to assign VIP status to particular email addresses, sending push notifications to the user when emails are received from that sender.
The Shared Photo Streams feature that will also be arriving with iOS 6 has been made available for the iPhone 3GS in the latest beta. Apple says Shared Photo Streams will be enable users to select photos to share with friends via iCloud.
Apple has now updated the footnote at the bottom of its iOS 6 preview web page to suit these changes, and the small print notes that these features are subject to change.
Take a look at our chart to find out which iOS 6 features your device will have.