I'm about to publish an app on the app store, and I'm looking to set the minimum OS version as it appears in iTunes as "Requires iPhone OS 3.x or later". 2 questions:
1) Where do I set this in my Xcode project?
2) I'm aware of the UITableViewCell numberOfLines property that is present only in OS > 3.1. If I set my minimum as OS 3.0, will people who have 3.1 be able to see the number of lines properly as I coded? (Obviously people on 3.0 won't be able to)
Thanks.
What you need to do is change the Deployment Target setting in your project. The Deployment Target specifies the minimum OS you would like your application to run on. This is regardless of the SDK you build against, which should always be the most recent SDK so you can ensure your application runs correctly on the most recent OS version available. So, in short:
- Set the Base SDK to be the latest OS available
- Set the Deployment Target to be the earliest OS you'd like your app to run on.
To answer your second question, if you set the Deployment Target to 3.0 your 3.1-only code will no longer compile. There are workarounds to that problem, however.
来源：https://stackoverflow.com/questions/1712023/set-minimum-iphone-os-version-for-app