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.
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However, it appears as though Apple really wants iPhone 5 users to update to iOS 10.3.4 right away otherwise they risk turning their devices into a useless brick. Apple is making this very clear using a notification sent to iPhone 5 devices the world over that haven't been updated to iOS 10.3.4 yet.
The last date for updating to iOS 10.3.4 is November 3, after which services like email, App Store, iCloud and many others will cease to work completely. This also means that you won't be able to update your iPhone 5 over the air, forcing you to connect to your Mac or PC and then either using Finder or iTunes in order to go ahead with a backup and the restoration process.
We are still a few days away from November 3, therefore it is recommended that you download iOS 10.3.4 right now straight onto your iPhone 5. You may do so by going to Settings > General > Software Update. Tap on Download and Install as soon as iOS 10.3.4 shows up.
Since over the air updates are a part of Apple's services (obviously) therefore you won't be able to perform the update after November 3. Right now, this very moment, the update will be available to you for download. Once you cross the November 3 threshold, then things will get a little rough for you.
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If you are looking to take the clean install route, you may do that as well. Just download iOS 10.3.4 from the link below and restore using iTunes.
I really can't emphasize much on the fact that you should simply go ahead and install this update. I understand that the iPhone 5 is an old phone at this point, but it is a solid daily driver for a lot of people at this point. With Apple issuing updates even after ending software support for it goes on to show how much the company actually cares for its users and their user experience.
News Source: Apple