Will the other party know when they read the intercepted message?

1, SMS blocking settings. If the other party sends a message with a delivery report, then after you intercept it, his mobile phone will receive a short message, indicating that the message was not sent successfully. In this way, the other party will know.

2. If the delivery report is not received by the other party's information settings, the other party will not know your information after it is intercepted. Only you can't receive his message because it has been blacklisted. If you need to see it, you have to open the SMS record of the blacklist to see it.