I stand corrected, they managed to officially certify it chapter III.
But in some countries it is not accepted in the night hours, as it is considerably louder than most other Chapter III aircraft. Some don't even count it as Chapter III as it is one the very edge of satisfying the Chapter III noise limits. Strictly measured it doesn't.
Germany for example prohibits MD8X departures after 10 pm on most airports, as it is not in the "bonus list" (most other Chapter III aircraft are).