SM Entertainment addressed people's confusion on December 2. The agency said, "It appears people are saying that EXO will be promoting as a sub-unit with three members, but they are not an official unit; rather, they are part of a special stage."
The rep continued, "It is true that Baekhyun, D.O, and Chen sang the title song for this album, 'Miracles in December.' We also plan on dressing the three of them up for this week's music shows . . . However, this does not mean they are officially promoting as a sub-unit. We are planning to henceforth have other members also go up on stage for varied performances.
We are preparing diverse performances because this album is a special album that captures the essence of winter and is filled with thanks for the fans. In addition, we plan to have only three members on stage just for this week and believe it is not correct to call this a sub-unit activity."
The album will be released on December 9, but you can see them on music shows starting this week!