User blog comment:Miskos3/Fairy Tail OVA 8: Natsu vs. Mavis, Review/@comment-26389992-20161204132437/@comment-2214433-20161204144241

It might be both. From what I know, the omake that the OVA is based on is also included with the DVD, so if I understand it correctly, the Christmas one will also include this afterstory, which will also be a part of the OVA itself.