Pokémon Shuffle Version 1.1.4 is available for players of the game and the patch adds the Shaymin Challenge. Also, to celebrate the 4 millionth download of the game, players can receive the
Complexity -1 item.
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/44/