User blog comment:Miskos3/Fairy Tail Episode 242: Tartaros arc: Kill or Let Live, Review/@comment-26263257-20150720140127/@comment-2214433-20150720140430

They actually remixed quite a few soundtracks from the old anime, but they are still considered 'new' and are added to the new OSTs. Like the Sting and Rogue theme or Celestial Sprit King one.