Many iPhone users, especially iPhone 6s users always complain their iPhone’s battery. As an iPhone 6s user, I encountered the problem that my iDevice shut down suddenly. I tried may methods to fix this problem, but the problem persists.

Then the solution appeared that Apple have an iPhone 6s Program for Unexpected Shutdown Issue/battery replacement service.

Depending on your serial number, you may be eligible.

Simply enter your serial number here and find out: https://www.apple.com/uk/support/iphone6s-unexpectedshutdown/

If you are eligible, they will replace it for free.

Just thought I'd mention this, some of you might have a 6S with a deteriorating battery, so worth to have a look if you're eligible for a free replacement.