I'm wondering the same - the only way to put it out of use is to set it as invalid or invalid-temporary. The same logic is used with users, responses, etc (no delete?)

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This may sound stupid but how do you delete a Queue under the [Queue Management] if it's no longer needed ?

This is true, the underlying database schema requires this behaviour. If you'd delete queues, you'd lose the relationsship in your ticket history, f.e. Set it (to invalid) and forget it. Or, even better: Keep it in mind for later use - you can for sure reactivate it at a later point in time and then rename it to s.th. more suitable than the name it probably has now ('test'?). Hope this helps, Robert Kehl