This is used to unlock the full features for Silent SMS. Please download and install Silent SMS before downloading this.
Silent SMS is a sms filter, it allows you to define rules for incoming SMS to whitelist or blacklist. If a SMS contains a words or phrases or a pattern characters that should be blacklisted, it will receive the SMS without notification.
Pro version allows for blacklisted SMS to be discarded and not saved into your SMS messages.
After enabling notification in Silent SMS, you need to go to the default SMS application and disable notification otherwise you will hear your phone beep twice upon every SMS received.