Interesting that you mentioned this. Did you see the post from swordmaker about the class action lawsuit from frustrated 4s customers? Apple could end support for older phones thereby forcing customers to buy newer phones. They did this with my ipad and apparently the recent iPhone OS update degraded the functionality of the 4s. So the hardware and battery might be just fine but the phone will be unsupported.
Software companies abuse their companies like this all the time. I’ve heard about this lawsuit but not followed it closely. I wonder if some third party can provide a bootleg operating system.
The iPhone 4s IS supported under iOS 9 and later versions of iOS 9. My girlfriend's employer supplied iPhone 4s was upgraded to iOS 9.2 and works just fine. It is no speed demon like her personal iPhone 6, but its hardware is eight times slower than the iPhone 6's hardware and sixteen times slower than the iPhone 6S's hardware. It still works but it is hardly a brick.
This class action lawsuit, like the previous ones based on the same argument, will be tossed out for lack of evidence. The plaintiffs cannot prove their contention that Apple deliberately made iOS 9 to obsolete the iPhone 4s. . . because it still works on the iPhone 4s.