What’s the difference between Instant Update and Resubmit?

[AlexandraKeymaster]

You have two options to update your live app in Google and Apple Stores: Instant Update or Resubmit. Global app changes like color scheme, app icon, splash screens, or adding brand new features that have not been previously supported, require Resubmit. Quick content updates require Instant Update only.
Under Submit settings, select the Store, Choose how you want to update Live App, select either Instant Update, or Resubmit. With the Force Update option unchecked, your app users will see the message in the app stating that the content of the app has been updated, with this option checked, app users will not see this message.