We were on the Wonder 7 night over the most recent NYE. It was our formal night, which as I understood, they try to schedule that way whenever possible. I'm not sure it was any more formal than a regular formal night though. We were on the dressy side of the crowd, not wearing full-length gowns, but cocktail dresses and suits. Many people changed after the dinner/show portion of the evening, b/c they didn't want to attend the deck party / fireworks in dressy clothes. I hope this info helps!