https://wccftech.com/pokemon-brilliant-diamond-shining-pearl-day-one-update-confirmed/

Pokémon Brilliant Diamond & Shining Pearl will get a day one update when they release next week, Nintendo confirmed.

The day one update confirmation has come via the Japanese Nintendo Store website, which also confirmed that the total file size for both games including the update will be around 8 GB. We currently do not know what will be included in this update, but we will surely learn more about it in the coming days.