Pokémon Shuffle Version 1.1.9 is available for players of the game and the patch adds the Groudon Stage, 15 new Normal Levels and Expert Stage 21 featuring Genesect. The Groudon stage will be available to play between April 13th, 2015 until April 27th, 2015.
Details of this event have been added to our Pokémon Shuffle Special Event page.
Source:
http://www.pokemon.co.jp/ex/poketoru/news/post.php/30/