Yes, I have been using it every day since 2016 and I have never missed any feature from the new iPhones. I have iOS 13.3 on it today in 2020 and everything works smoothly. I only had to change the battery once, then everything ran like new again!

iOS 12.1.1 is supported on 6s. However, the product is cheaper elsewhere despite the adjusted price of CHF 349. Unfortunately, because I like to shop at Digitec.

Sure, iOS 12.1 is supported on 6s