Xcode minimum deployment target

You can set the deployment target in your project’s target’s general settings . You can read more about this in Apple documentation “Setting Deployment Target”.

The deployment target, which is the earliest iOS version on which the app runs . The devices for which to build the app . The main user interface file to load when the app launches . The user interface orientations (portrait, upside down, landscape left, landscape right) that the app supports.

You can set it based on your choice , if you would like to cover all the users using iOS devices then you can set deployment target to 10. x OR as per the latest analytical data from the Apple, there are only 7% devices using iOS 10. x or lower, so you can ignore them too and can set deployment target to 11.