Nintendo has announced that the Version 1.2.0 update is available for Pokémon Brilliant Diamond and Pokémon Shining Pearl as of February 21st, 2022.
On February 21, 2022, a new software update for Pokémon Brilliant Diamond and Pokémon Shining Pearl became available for download. Please take a moment to download and install this update while your Nintendo Switch console is connected to the internet.
Complete these steps
- Connect the Nintendo Switch console to the internet.
- Return to the HOME Menu and launch the game.
- The update will be downloaded and installed automatically.
- Once the update is installed, the newest version number will be displayed on the title screen.
Ver. 1.2.0 (Released February 21, 2022)
- Union Room functions have been expanded.
- The maximum number of players you can play with via local or internet communication in Union Rooms has been increased to eight. Also, by selecting Greeting or Capsule Decorations, you can show each other your Trainer Cards or Capsule Decorations.
- Additional Colosseum battle feature has been added.
- Enter the Colosseum on the 2nd floor of a Pokémon Center to battle with other players using custom rulesets.
- In the Colosseum, you can set rules, such as the number of Pokémon to send into battle as well as their levels, and play Single Battles, Double Battles, or Multi Battles via local or internet communication.
- Pokémon Trading and Battles
- Some Pokémon acquired via unintended methods or illicit modification now cannot be used in Link Trades or Link Battles.
- Fixed some issues for more pleasant gameplay.
Source:
https://en-americas-support.nintendo.com/app/answers/detail/a_id/57058