The Android development app signature has expired. You can uninstall the application and reinstall the latest version. Because all android applications require developers to digitally sign with certificates, Android will not install unsigned programs, and the role of signing is to prevent the programs from being tampered with.

Another function of APP signature is application upgrade. If you want to upgrade the version of the application, you must sign it with the same certificate, because the system will only allow you to install and upgrade this application if you sign it with the same certificate.

If users sign with different certificates, the system will ask your application to change its name, which is equivalent to installing a new application.

Extended data:

Application of app signature in data sharing;

If different applications want to share data or code, they should run in the same process and sign with the same certificate.

Sign multiple applications with the same certificate, and use the permission check based on signature to enjoy the code and data between applications in a safe way.

Baidu Encyclopedia-Application Development