This letter was written not long after the episcopal ordinations of Augustine and Alypius (AD 395). We learn from it that the practice of allowing the presbyters to preach was still a novelty at the time. However, if Augustine and Alypius praised Aurelius for allowing it in Carthage, we may presume that they followed suit in Hippo and Thagaste.
It is interesting to see, however, that the presbyters seem to be allowed by Aurelius to preach only in his presence.