You must first understand what causes it. Basically, it is the incompatibility between software and system. Rarely because of the signature problem, in this case, it can't be repaired, or you have to download it again. At present, the number of mainstream third-party application stores in China will be better. You can download it, bind the APPLE ID on the synchronous push, and the synchronous push will give you an official download channel. The software has high compatibility and stability, will not flash back, and can be free.