I just checked the UFC rules on their website and the 12 to 6 elbow is still banned. It does say that any angle or curve added to the strike makes it legal, so theoretically an 11:30 to 5:30 elbow would be legal. It probably comes down to how close to vertical you can make the strike before the ref can’t tell the difference and penalizes you.I hear that they made the 12 to 6 elbow legal but strike to the back of the head are still illegal as it should be. They may come to regret it later on. It just depends on how much dedication fighters will put into being good at driving the power for it.