Use this method to change your app's icon to its primary icon or to one of its alternate icons. You can change the icon only if the value of the supportsAlternateIcons property is true. You must declare your app's primary and alternate icons using the CFBundleIcons key of your app's Info.plist file. For information about how to configure alternate icons for your app, see the description of the CFBundleIcons key in Information Property List Key Reference. Apple Developer
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