The Pokémon Trading Card Game (TCG) Online app will be removed from the App Store, Google Play, and Pokemon.com prior to the official global launch of Pokémon Trading Card Game (TCG) Live, which is now available in beta to players around the world on iOS and Android devices, as well as PCs and Macs.

Card Set Development Ending for the Pokémon Trading Card Game Online

To devote resources to the Pokémon Trading Card Game Live, card set development for the Pokémon TCG Online will end on March 1, 2023.

With the upcoming sunsetting of the Pokémon Trading Card Game Online, no further card set development will be supported in the game as of March 1, 2023. Pokémon TCG: Crown Zenith will be the final expansion to be incorporated into the Pokémon TCG Online in order to devote all resources to Pokémon Trading Card Game Live, which is now available in beta to players around the world on iOS and Android devices, as well as on Windows and macOS devices.

The in-game Versus Ladder reward tracks will continue to update leading up to an eventual game sunset, but no further updates will come to the Pokémon TCG Online outside of potential bug fixes. Also, the 2023 Standard format rotation and Pokémon Tool card errata will not be applied in the Pokémon TCG Online.

Source: https://www.pokemon.com/us/pokemon-news/card-set-development-ending-for-the-pokemon-trading-card-game-online

Pokémon TCG Online Sunset FAQ - When will the Pokémon TCG Online be sunsetted?

The Pokémon TCG Online app will be removed from the App Store, Google Play, and Pokemon.com—and game servers will be shut down—prior to the official worldwide launch of Pokémon TCG Live, which is now available in beta to players around the world on iOS and Android devices, as well as PCs and Macs.

While the Pokémon TCG Online will remain active during the Pokémon TCG Live beta, which is now available globally, no new Pokémon TCG products, cards, or deck accessories will be added to the game following March 1, 2023. This update will help ensure that more development resources are dedicated to making Pokémon TCG Live the best experience possible for players. While no new content will be supported, the Pokémon TCG Online will continue to support new Versus Ladder reward tracks (using items that were available in-game prior to March 1, 2023) and bug fixes, as necessary.

Will I still be able to redeem codes in the Pokémon TCG Online after March 1?

If the code comes from a product that’s already supported in the Pokémon TCG Online prior to March 1, 2023, it will continue to be redeemable up until the Pokémon TCG Online is sunsetted. Code cards from products that were not supported in the Pokémon TCG Online prior to March 1, 2023, will be redeemable in Pokémon TCG Live only.

Source: https://support.pokemon.com/hc/en-us/articles/4406895467668