Currently some messages cause an audible ding, and some don't. Please consider making them all do it. Or, preferably, an option to ding or not ding. Or, even more preferably, different such options for each possible message type.
For example, I really don't care all that much about "has leveled up", which currently dings. But I care a lot about "has been completed", "has been fully repaired", and "has been destroyed", none of which currently ding.