The iPhone 18 Pro Max features a significantly larger battery, exceeding 20 watt-hours, which triggers additional shipping regulations in most countries. To comply, Apple implemented an innovative battery-firmware solution that limits capacity below 20 Wh during manufacturing and transport. Once activated by the user, the full capacity becomes available.

For scenarios like repairs, trade-ins, returns, or gifting, Apple introduced a new 'Prepare to Ship' feature in iOS 27 Settings. This function discharges the battery below 20 Wh and maintains a charge limit to meet shipping requirements. The process may take minutes to a couple of hours, during which the device may feel warmer—expected behavior.

Upon completion, Settings shows 'Ready to Ship' with a red badge. Users can continue using the device normally during discharge, except after erasing the iPhone. Access the feature via Settings > General > Transfer or Reset iPhone > Prepare to Ship.

Apple’s support document details the full process.