When notifications-backend receives a Kafka message on the platform.notifications.ingress topic, it will look for the rh-message-id header and perform deduplication if that header is available. Otherwise, the message will still be processed but without deduplication.

This has been integrated already in policies-engine and notifications-gw.

We need to inform the onboarded apps of the existence of this new header and that they should start sending it with each Kafka message. Its value has to be a byte array obtained from a valid UUID version 4 string encoded with UTF-8. For example, in Java the value would be generated with:

UUID.randomUUID().toString().getBytes(UTF_8)

First, let's wait at least one week on production with the latest notifications and policies deployed. After that, we can inform the onboarded apps.