I have a handy little 'Power Bank' case on my iPhone 5s and as soon as I updated to iOS 8 it is now an unsupported accessory and will no longer give me juice. Lame.
Probably didn't license their chips from Apple... 3rd party parts.. gotta watch them... They can find a way to sneak it through the current generation, but if it doesn't have Apple's little tattle tail chip in there, then you'll be out the money come the next update. I don't support Apple's little method of making sure that they get money for everything anyone sells, but knowing that it's there, you have to choose carefully what you buy.