In February 2020, Nintendo announced the launch of the Pokémon Home platform, which, in a nutshell, is a Pokémon storage, exchange, and transfer service that covers all the little monsters in the series, including Pokémon Go.
At the time, the service was sold as a "successor" to Pokémon Bank, as it could use small monsters captured in older games on the current Nintendo Switch, such as Pokémon Let's Go and Sword/Shield. When announcing new games like Pokémon Brilliant Diamond and Shining Pearl (BDSP) and Legends: Arceus, the company confirmed that they will also integrate Pokémon Home, but according to people familiar with the matter, that may not happen.
Fans have been waiting for Pokémon Home to incorporate into the latest little monster games, especially the Diamond and Pearl remake released last November.
Even though Nintendo has confirmed that the game will support the service, the company has so far not commented on the matter, and despite rumors that the update should arrive this month, it's all speculation, much to the dismay of some fans.
Things got more confusing this week when a data miner known for analyzing the code of Pokémon games said the integration of the Brilliant Diamond and Shining Pearl games seemed unlikely.
SciresM pointed out on Twitter that Pokémon BDSP uses a completely different development platform than other Pokémon games, which may prevent them from connecting with Pokémon Home.
Pokémon Brilliant Diamond and Shining Pearl are games made with Unity. Typically, Pokémon games, including Pokémon Home, are made in C++ using a custom engine ("gflib/gamefreak lib"). Since they are Unity games, the Pokemon BDSP save is actually a C# object serialized to disk. There is no specific rating that may change between versions.
Adding family support means analyzing the source of the Pokemon and updating the save file. But we're talking about a C# framework that doesn't use specific serialization with multiple versions. They will need to convert the non-unified C# unified objects in the non-unified codebase. It has to be a huge encoding anyway.
In short, the coding language of the Pokemon BDSP is different from the other games in the series, and therefore not compatible with Pokémon Home. To achieve this, ILCA, the developer of Pokémon Home and Pokémon BDSP, and Game Freak, the developer of other Little Monsters games, will need to develop serialization transforms and other games for the game in a format compatible with the storage platform, which seems rather complex.
As for Pokémon Legends: Arceus, the data miner said there is no explanation for the delay in integrating with Home, as it uses the same programming language as Home, however, Nintendo must still wait for the method to integrate Pokémon BDSP with Home before upgrading to the latest games service. If you want to buy SWSH, BDSP, PLA Pokémon you can find them at PKMBuy. SWSH and BDSP Items are also available.