My iPhone 4S is getting old now, and so is the battery: Almost 1.000 charge cycles done (986) and the max capacity is only 1197 mAh now, instead of the original 1430 mAh.. Is it worth buying a new battery in this case? Because I hear a lot of people claiming that it would be more like a placebo, and that since iOS 7+ you would never get the same battery power out of it as it used to be on iOS 5-6. Is there any way to get a better view/calculation on what the improvement actually would be? I mean yes the max capacity would go up from 1197 mAh to 1430 mAh then, but I suppose that doesn't actually mean I would get 16% more battery life out of it then, or is that really true? Oh and about the replacement itself: I was thinking of sending it to Apple for a new battery (price doesn't matter), but I'm worried that this would mean getting iOS 8.1.2 on it.. right? I really like 7.1.1 jailbroken and don't want to upgrade at all, so does really everything you send to apple (even if it's just for a battery replacement) means you'll be getting the new OS on it? Because if that's the case, the only solution is taking it to a third party repair shop who'll do it quickly and for a few bucks. But then again I don't know where the battery would come from, probably somewhere cheap on let's say eBay or something... The idea of getting a replica/non-apple battery scares me: I suppose cheap batteries aren't the same in quality and have increased risk on overheating? Any help would be very much appreciated, thanks!!