Why do I get this message?
You may come across an "Important Message" from Apple regarding your battery, display, or camera. These messages are displayed to inform you that repair work has been done on your device, specifically on the replaced component such as battery, screen, or camera (depending on your iPhone model). However, only an Apple Genius Bar or an Apple Authorized Service Provider can replace a component in the latest iPhones without triggering this notification.
How long will these messages be there?
These messages do not affect your device's performance and are visible on the lock screen for 4 days and then for 15 more days in Settings. It is essential to note that getting this message doesn't imply that your battery has any issue or is defective - it only means that it was replaced with a new battery that works as efficiently as the original one.
The types of messages you may see depend on the iOS version you are using. For iOS 15.2 and later, you can go to Settings > General > About > PARTS AND SERVICE HISTORY to see which components, if any, have been replaced. You'll see "Unknown Part" if the component installed is not a genuine Apple part, and "Genuine Apple Part" if the replacement was done using genuine Apple parts and processes. It is important to note that these components are functionally identical to the Original Equipment Manufacturer (OEM) equivalents and won't perform any differently, even if replacements are not performed by Apple.