1. Please upgrade to the latest IOS 17.5.1 version before installation (Note: the old battery must be an original battery that can display the health percentage. OEM batteries or original batteries that display the repair status are not compatible) 2. If the IOS system is 17.3.1 or an older version, you can order and install CK batteries, and the battery can normally display 100% health. (Note: the old battery must be an original battery that can display the health percentage. OEM batteries or original batteries that display the repair status are not compatible) 3. If you need to install CK batteries in a mobile phone with ios system 17.4 or 17.4.1, you can only display 100% health by upgrading to version 17.5.1 or flashing the system version to ios17.3 or an older version (note that flashing requires skilled technicians to operate). 4. No matter how the mobile phone system is upgraded, CK batteries can ensure the normal use of the battery. It’s just a problem with the battery health display. If you don’t mind this, you can place an order to purchase CK batteries normally.