By calling people through WhatsApp, hackers figured out that they could infect phones with spyware called Pegasus. Pegasus enabled hackers from remote locations to gain access to everything in the infected phone. Thats the content of messages and files to data about that phones location.

Is WhatsApp really secure?

WhatsApp prides itself on its encryption, “your personal conversations are still protected by end-to-end encryption,” it says, “which means no one outside of your chats, not even WhatsApp or Facebook, can read or listen to them.”

Can anyone see deleted WhatsApp messages?

Theres no official way through which you can retrieve the deleted messages on WhatsApp. WhatsApp introduced the Delete for Everyone feature in the year 2017. After this feature was introduced, the person who received the message will get a notification of the message being deleted.