Here is the list of Apple devices that will get iOS 11
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Тhe full list of iOS 11-compatible devices includes the iPhone 5s and newer iPhones, all iPad Air and iPad Pro tablets, the 2017 iPad model, the iPad mini 2 and later models, as well as the 6th generation iPod touch. Here’s is what this list looks like on Apple’s site:
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It is interesting to see that the iPhone 5s – a model launched in 2013 – is to be upgraded to the new OS. Android phones, in comparison, get 2 years worth of updates at best. Тhe iPhone 5 and the iPhone 5C are obviously not going to get iOS 11, so if you're still holding on to one of those, perhaps it is time to consider upgrading.
source: Apple
Things that are NOT allowed: