The application to spy on WhatsApp conversations is simply spectacular, programmed and designed for easy use, which gives it a plus compared to many other methods that we already know, and which in turn are very complicated to apply.
The application works through a vulnerability found, better known as vulnerability 0, which allows us through an SQL injection with an encrypted method to access several of the WhatsApp servers and thus gain access to conversations and other files hosted on it, that is why as long as the vulnerability is not patched we can continue to see many WhatsApp conversations without any problem. Do you find it hard to believe? I encourage you to try it, you have nothing to lose.