Every so often, game developers will distribute a “patch” for games they’ve released. These patches usually apply to downloadable (digital) games, though they’re often utilized for retail releases, too. Games on the Nintendo 3DS eShop are subject to updates and patches too, and it’s recommended you apply them as soon as possible: Patches often fix bugs and/or add new features.
Patches and updates for Nintendo 3DS eShop games are free and easy to download and apply. Here’s what you need to do.
1) Turn on your Nintendo 3DS.
2) Make sure your 3DS’s Wi-Fi is enabled.
3) Tap the Nintendo 3DS eShop icon on the Main Menu.
4) If any of the games you bought need to be updated, you’ll automatically see a message telling you so. You can choose to update at that moment, or later on.
5) If you choose to update your games later, you can view the list of available updates via the eShop’s Settings/Other menu. Tap “Updates” under the “History” category.
6) You should see a list of games that are updatable. Tap “Update” to re-download the game with the updates applied. As with other eShop downloads, you can choose to Download Now or Download Later.
Updating your games shouldn’t hurt your save files.