In the Generation Showdown Online Competition, players duel in epic battles using virtually any known Pokémon! The Generation Showdown is a Double Battle event, and any Pokémon in your party higher than Lv. 50 will be set to Lv. 50 for the duration of the match. Each team will be able to have up to two special Pokémon, such as Legendary or Mythical Pokémon.

Sign-Up Period: Thursday, February 5, 2015, at 00:00 through Thursday, February 12, 2015, at 23:59

Competition Period: Friday, February 13, 2015, at 00:00 through Sunday, February 15, 2015, at 23:59

http://3ds.pokemon-gl.com/information/9ac897fa-9650-481d-b3ae-657971b5a606