When Apple announced that iOS 6, the latest version of its mobile OS, would work with older devices all of the way back to the iPhone 3GS, people cheered. It's not typical these days for major software updates to support 3 year-old products.
But don't give Tim Cook and company the Nobel Peace Prize just yet. Some two-year old devices, like the original iPad, aren't getting any iOS 6 love. And even the ones that are supported aren't guaranteed to have access to all of its features...