"Hi Evagorasc, Belisarius is right in his main argument: Batteries are consumables and degrade according to the way they are used. However, he only focuses on that, he has obviously not felt the realisation of having upgraded to IOS 10 and his battery suddenly drains and goes bang. Like we have, to us it is obvious, IOS 9 = fine, IOS 10 = dead.
The proof is that in an unheard of turn of events, Apple released in depth battery diagnostic tools in 10.2."
Adrian, I am beginning to think that the Sep 2014 launched iPhone 6, and the new thinner larger battery format. As of Nov 2016 and over 500 cycles, they are done. Period. Two long years of heavy usage-as yourself admitted.
So two years into this process, yes Apple released 10.2 diagnostic. But I believe it is to address the complaints of battery issues failures and identify them as they were building up. But I was aware of a small number of people complaining since iOS 7, and yes, iOS 9 with iPhone 6 and 6S.
Unfortunately a technique called Competing Hypotheses eliminates the iOS as a culprit. Your hypothesis that iOS causes it must be universally applicably yet it is not. Hundreds of millions of iPhone users have no issue.
An iPhone 5 whose battery I had replaced, it was about 6 months old and acted with iOS 7, the day off. Apple replaced the battery. the iOS did not kill it- it was justa poor battery. The replacement worked perfect for 2 years after.
It is more like Your battery is defective and hanging in with iOS 9 hanging up. iOS 10 exposes the flaw and it dies in 60 days. Or the battery stress of install and maybe some fast draining apps exposed again an inherent weakaness.
Am I right in saying, Apple released an update which has made a lot of people's iPhones unusable?
Not at all. Over 500 million users of iphones 5 to 6S updated successfully. That was repeated several times by Apple while monitoring iOS 10 deployment. Your particular 6 battery has likely a shelf life of 2+ years, approaching 600 cycles and likely just died as it was supposed to, as a consumable.