Major software updates have always been a tricky thing, and for the most part Apple has handled them about as seamlessly as possible during the course of the iPhone and iPad's existence. Still, while the vast majority of iOS users upgrade to the latest versions of their device's operating systems, there are many people who either don't bother or don't care to update their devices, for whatever reasons.
I've heard it many times over the years when a new game releases and in our forums somebody is hollering something like "Why does this require iOS 6 or above!?" Oftentimes those users refuse to update in order to preserve a Jailbreak, or they're waiting for the new version of iOS to get a few updates under its belt in order to have all the bugs worked out, or their device is just plain too old and Apple drops support for the latest iOS on them.
Whatever the case, it's a thing that happens, but Apple might be offering up a solution on the cusp of iOS 7's release this week. Users on Reddit have noted that a new pop-up appears when they're trying to download an app that isn't compatible with their particular version of iOS, and offers them the ability to download the last compatible version of that app instead.
While this seems like a step in the right direction for owners of older hardware or those who just choose not to update iOS, it hasn't officially been acknowledged by Apple in any way. It appears to be an option Apple can enable server-side, so it could just be that they're exploring this kind of feature at this point in time. However, as major retailers and Apple themselves roll out device trade-in programs, as well as Apple's push into emerging markets, there's bound to be a whole bunch of older devices out in the wild, and this new feature instantly makes all those devices much more useful.
We'll keep tabs on this story and let you know if Apple announces anything official.