For some weeks now, we have all been getting a notification in WhatsApp chats that announces the new security measures that the service has implemented to prevent third parties from intercepting and reading our messages.
Now all conversations are transmitted securely, that is, encrypted and can only be read by the sending and receiving devices. For it to work, both phones must have the application updated to the latest versions and in the case of groups, all its components must already have the latest versions installed. That is why notifications have been appearing gradually advising of “end-to-end encryption”, and it is even possible that in some chat or group it has not appeared yet.