iOS 11 release date, key features and what iPhones and iPads can I get it on?

It will also be compatible with the following iPhones, iPads and iPod models:

iPhone: 5s, 6, 6 Plus, 6s, 6s Plus, SE, 7, 7 Plus

iPad: 5th generation (2017); Mini 2, 3 and 4; all Air models and all Pro Models

iPod Touch: 6th generation (2015)

How do I get it?

iOS 11 will be available on all devices from the iPhone 5s and later. When it is made available, simply go to Settings -> General -> Software Update.

Some developers have already had early access to iOS 11, by signing up to Apple's Beta programme.

Source: iOS 11 release date, key features and what iPhones and iPads can I get it on?