A new guest has arrived in Pokémon Masters EX! You can invite Hau to the Trainer Lodge after you team up with 4★ Hau & Raichu! The Lodge Exchange has also been updated, so you can get exclusive presents for Hau—plus other useful items!

Updates to the Trainer Lodge

The following updates were made to the Trainer Lodge.

• You can now invite Hau to the Trainer Lodge.
  Note: You can invite Hau once you have teamed up with 4★ Hau & Raichu.
• The Lodge Exchange lineup has been updated.

Important

• To use the Trainer Lodge, you must have completed Main Story Chapter 1: The More the Merrier (Normal) in single-player.
• The content is subject to change without notice.

Source: https://pokemonmasters-game.com/en-US/announcements/Update_8060_1W_4