ios updates up to how many years

There is no standard advertised iPhone iOS update cycle count guarantee. While the original iPhone and the iPhone 3G received two major iOS updates, later models have typically gotten software updates for five to six years. Having been shipped with iOS 9, the iPhone 6s became the first generation to see a seventh iOS version, making it the technological equivalent of a tortoise outlasting generations of humans. See the image below, and read https://www.statista.com/chart/5824/ios-iphone-compatibility/ for more details.

It varies. For major releases, 16 supports the iPhone 8 and newer, and Apple occasionally patches older units; it's likely that nobody at Apple has decided when they're going to stop either type of update for a 12.

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