Depending on the nature of the update, iPhone updates are generally 3–5 generations back. Just on the iPhone side, iOS 10 has some level of support on the iPhon

Depending on the nature of the update, iPhone updates are generally 3–5 generations back. Just on the iPhone side, iOS 10 has some level of support on the iPhone 7 (current generation); iPhone 6s (-1 year); iPhone 6 (-2 years); iPhone SE (slightly updated iPhone 5s); iPhone 5s and iPhone 5c (-3 years); and iPhone 5 (-4 years). That’s five generations of support for iPhone. They are a little more aggressive with iPad and iPod touch deprecation, but I think that’s because some of those devices were built underpowered anyway.