Semblances no longer draw from your aura reserves. We came to include this change after going back to the tourney matches from the third volume. Despite contestants using their semblances, their aura meters stayed the same. If someone has 1% of their aura, they can use their semblance. If someone has 0% aura they canNOT use their semblance. That being said, THIS DOES NOT MEAN YOU CAN SPAM YOUR SEMBLANCE!! Use reservation, semblance still take a toll on you, just in terms of fatigue after extended use.
By default, from now on, semblance will not take a toll on their users aura, HOWEVER, if you wish to keep the previous system of combat, you must be the thread creator and mention that the thread is using the system at the start of the thread or inform all participants beforehand.