In my App i am using NSUserDefaults to save some data. I have a doubt regarding this when i update the app in App Store, Will The Data in NSUserDefaults will remain same or it is removed.
No, it will not be erased on updating
NSUserDefaults will not be erased during update, but it will be removed when you uninstall an app.
来源：https://stackoverflow.com/questions/8208485/does-nsuserdefaults-get-erased-when-an-app-gets-updated