https://www.forbes.com/sites/ewanspence/2017/12/20/apple-iphone-kill-switch-ios-degrade-cripple-performance-battery/#3bf0f4fc16a8 Apple statement :  "Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices. Lithium-ion batteries become less capable of supplying peak current demands when in cold conditions, have a low battery charge or as they age over time, which can result in the device unexpectedly shutting