Quality Of Service: DUPLICATES_OK
33.4.2. DUPLICATES_OK With this QoS mode, the messages are consumed from the source and then acknowledged after they have been successfully sent to the destination. Therefore there is a possibility that if failure occurs after sending to the destination but before acknowledging them, they could be sent again when the system recovers. I.e. the destination might receive duplicates after a failure. This mode is available for both durable and non-durable messages.