We have recently added a check on Duplicated ClientIDs based on integration tests:

- That we can't have two connections using the same ClientId.

Reading the JMS Spec, section 4.3.2, it clearly says that "such an attempt of sharing individual clients shouldn't result in messages being lost or doubly processed".

so, I read from that that there is no requirement from the spec about ClientIDs.. You could even have multiple Subscriptions with the same ID as long we share the load with them without creating duplications or loosing messages.

So.. we will be dropping that check.