Similar issue with the 6S happened when ios 11 was released. In that case Apple ...

		JustSomeNobody on April 10, 2018 \| parent \| context \| favorite \| on: iOS 11.3 update breaks iPhone 8 devices with third... Similar issue with the 6S happened when ios 11 was released. In that case Apple DID allow people to downgrade (back to 10.3.3 in fact!). I don't have a third party screen, but I did take advantage of that and tried ios 11 for a while. Eventually went back to 10.3.3 before that window closed (they fixed the issue with 3rd party screens on 6S).