Apple's mobile phone is the fourth generation, there is no jailbreak, and there is not much software. I just downloaded a football with more than 500 MB, so I can't fit it. Just say that the signature of the application is invalid, Iphone can't install third-party plug-ins without jailbreaking (that is, it's not software downloaded from Apple Store, and Apple mobile phone is a closed system, so it can't download software from outside, specifically, it can be downloaded, but it can't be used). If you break out of prison (that is, crack it and let it unlock), you can use it.