https://wccftech.com/apple-will-brick-your-iphone-5-if-you-dont-update-to-ios-10-3-4-right-now/

If you are an iPhone 5 user, you must download iOS 10.3.4 for your phone right now or you risk losing web services, including App Store and iCloud.

Apple surprised everyone in July of this year by releasing iOS 10.3.4 update. It was a super important release that fixes a GPS-related issue so that services keep on functioning which rely heavily on accurate location, date and time. This includes services like the App Store, iCloud, email, web browsing etc. The update is available for both iPhone and iPad users.