The Pokkén Tournament DX Version 1.2.0 was released on January 30th, 2018 and it added Battle Pack Wave 1 compatibility and Nintendo Switch Video capture compatibility.

The Pokkén Tournament DX Battle Pack grants immediate access to Avatar items upon purchase and two waves of DLC as they are released. The Battle Pack contains 2 new Battle Pokémon and 2 new Support Pokémon Sets. With these Pokémon joining the fray, the battle is just getting started!

Wave 1 released on January 31st, 2018 contains the Battle Pokémon Aegislash, a new Support Pokémon set featuring Mega Rayquaza and Mimikyu and additional Avatar items.

Pokkén Tournament DX Version 1.2.0 Patch Notes:

• Pokkén Tournament DX Battle Pack Wave 1 compatibility has been added.
• Video capture compatibility added. Hold the Capture Button to capture up to 30 seconds of the previous footage.
  • The system must be updated to Ver 4.0.0 or higher to use this feature.

Additional Information:

• This update must be applied in order to use the game’s Internet features.
• Save data will still be available for use after downloading the update.
• If the system is connected to the Internet, the update will download and install automatically.
• Once you have updated the game, you will not be able to play back replay data from a previous version.

Complete These Steps:

1. Connect the Nintendo Switch console to the Internet.
2. Return to the HOME Menu and launch the game.
3. The update will be downloaded and installed automatically.
4. Once the update is installed, the newest version number will be displayed on the title screen.

Source: http://en-americas-support.nintendo.com/app/answers/detail/a_id/27506/~/how-to-update-pokk%C3%A9n-tournament-dx