If you are on an iPhone 5 or iPad 4 running iOS 10.3.4 or lower, you can fix this.
For iOS 11 or higher: You cannot run MC4 natively. The game is 32-bit, and iOS 11+ is 64-bit only. Your only option is an Android emulator on a PC. modern combat 4 invalid license fix
Since iOS removed 32-bit support entirely (iOS 11+), the game is officially dead on modern iPhones unless you have a jailbroken device on iOS 10. This guide focuses on Android, where there is still hope. If you are on an iPhone 5 or iPad 4 running iOS 10
For users on an iPhone 5/5c/6 on iOS 10 or lower: For iOS 11 or higher: You cannot run MC4 natively