The issue regarding IU's late arrival at the 'Dream High' concert has blown out of proportion however, IU personally released a apology earlier today. On February 25th, IU updated her me2day saying,

"Hello this is IU. I would like to apologize in a different manner but this is the only way for me to express my feelings so I'm sorry for posting this..�I sincerely apologize to all the people who have been hurt or displeased because�of me yesterday and today. I was thoughtless... The 'Dream High' concert was delayed because I was late. I'm very sorry to the audience, the cast, and all the people that were there. Also, I'm sorry for being immature and causing anxiety by posting words regarding a personal issue before apologizing. I was very flippant.. After being punished and regreting my actions, I will not make a mistake again. I will be a mature and adult-like IU. Those who have been disappointed because of me.. I promise you. Once again, I bow my head before many and apologize. I'm sorry."

The issue of her lateness arose due to her lack of an apology. Hopefully this apology will bring down the drama. Source: Medical Today via Nate