The Pokémon Centers in Japan have announced that they have renewed the Pokémon Center Birthday Event Pokémon but this time people will need to have a copy of Pokémon Sword or Shield to get a serial code for either Pikachu or Eievui. One event Pokémon gift will be given for each birthday even if you have more than one game. People will also receive a Birthday Crown, a Birthday Card and a coupon for 5% off their order. The distribution starts on November 15th, 2019 and players can get their birthday gifts on their birthday.


Source: https://www.pokemon.co.jp/info/2019/10/191025_p01.html