A few days ago, author Hiro Mashima had said that Rave Master, his first successful series and the one who designed him for Fairy Tail, would be getting a new feature soon.
And it was “announced” by the author himself. We still won't have the long-awaited animated remake of Haru's adventures, but at least we will have in anime the crossover made between Fairy Tail and Rave Master a few years ago, made by Mashima himself in a special chapter.
Finally, the episode will be animated in an OVA that will accompany volume 39 of Fairy Tail, which will go on sale on August 16th of this year. Furthermore, this is the second OVA in a row that accompanies a Fairy Tail volume, which will also have one in issue 38.