Due to various reasons such as regulatory violations, the app package that can be downloaded and installed from the application management program will be blocked by the application management program and users cannot download it. This is the so-called off-shelf app. In addition, after the iOS developer account expires, the App will be removed and needs to be renewed as soon as possible. After the account expires, the App corresponding to the account will be removed and users cannot download it. Users who have downloaded the App can still use it, and it will be automatically restored after renewal.