In MQTT, every client must have a unique ClientID. If two clients select the same ClientID, it would cause link stealing (i.e. the client who connected first would be disconnected by the broker). But in a multi-tenant deployment every user can, in his own account, connect clients with a ClientID that could collide with one used by another user (i.e. if 2 users use test-client).

Currently, it is not possible to change ClientID via interceptors (all fields in public final class MqttConnectPayload are final).

Would it be possible to add a new feature in the form of some low level "interceptor or divert" at the MQTT protocol layer in the AMQ Broker that would allow ClientID change?

It would be helpful to have ability to change ClientID also for AMQP protocol.

This worked for an old broker (AMQ 6.2 and 6.3).