Why does my iPhone show an Apple “Important Message” or “Unknown Part” warning?

A warning about the battery, display or camera means that the component has previously been replaced. On recent iPhones, only Apple or an authorised Apple service provider can replace certain parts without triggering these notices; the warning does not itself mean the replacement is faulty. It appears on the Lock Screen for a few days and remains in Settings. On iOS 15.2 or later, check Settings > General > About > Parts and Service History. Supported parts vary by model: battery on XR/XS and later, battery and display on iPhone 11–13, and battery, display and camera on iPhone 12–13. These notifications do not affect performance. Contact servizioclienti@comenovo.it if you need help.