问题
this is a very simple question I'm assuming. Can someone tell me what deployment target means. If I choose IOS 10, does that mean only users with iOS 10 can download the app. Is it bad to choose a lower deployment target? ALSO, continuing on deployment target, is it not recommended to run on a lower deployment target.
回答1:
Lets say you have set minimum deployment target to iOS 9. This means your application is compatible for iOS 9 and above devices.
The application won't run on below 9.0 devices but can run on any iOS version greater than iOS 9.0.
回答2:
The deployment target determines your app's ability to run on older iOS versions. When a new version of iOS is released, some people do not bother to update their devices to the latest iOS version.
If you choose higher deployment target (e.g 12.1), your app won't be able to download for the people who even have latest devices but have older iOS version.
If you choose lowest possible deployment target, some newer frameworks won't be able to behave as expected which increases the chances of app crashes for older iOS versions.
We have been using Deploymate for maximum backward support. It warns about newer APIs and frameworks and deprecated methods and then you start fixing for lower iOS versions.
回答3:
If you are new to Xcode, I suggest accepting the default, and thinking of it as a constraint on your project.
As newer of Xcode versions come along, support for older target values will be removed. Companies that have extensive customer bases have to deal with this problem in their own way.
In most projects I have worked on, the iOS version matters because it dictates which devices can run your application.
For example, iOS 10 essentially left behind all iPod-style connectors.
来源：https://stackoverflow.com/questions/41278392/what-does-deployment-target-mean