Following the release of iOS 11.3.1 on April 24, Apple has stopped signing iOS 11.3, the previous version of iOS that was available to consumers.
iPhone, iPad, and iPod touch owners who have upgraded to iOS 11.3.1 will no longer be able to downgrade to earlier versions of iOS.
Apple routinely stops signing older versions of software updates after new releases come out in order to encourage customers to keep their operating systems up to date.
iOS 11.3.1 is now the only version of iOS 11 that can be installed on iOS devices by the general public, but developers and public beta testers can download iOS 11.4, an update that is currently being beta tested.
Top Rated Comments
The reason is because they are always graphing and charting comparing how many are on the latest iOS compared to android when they stop signing prior iOS that's how they achieve those pie results.
And the guy clearly did understand how signing and upgrades work. Things happen to devices that require a fresh install.
Lastly, he didn't ask a question, so I'm not sure what the point of your final paragraph was. In fact, he stated a hypothesis (and a somewhat reasonable one at that). It should be noted that his hypothesis is not mutually exclusive with benevolent reasons to stop signing older versions too.
Less snark, less condescension, and more reading next time, please.
Additionally, you don't appear to understand how iOS signing and upgrades work. Customers can choose which iOS they want to keep on their phone. They just can't downgrade, or do a fresh install to an unsigned iOS.
Instead of coming up with wild conspiracy theories, you can try this newfangled tool called "Google" which lets you type in a question and receive answers. You will find that Google, combined with your question, will yield the exact reason why Apple stops signing older versions of iOS. Because, strangely enough, this topic has in fact been covered to death many times before.
(I sure hope it does- cuz it sure needs to)