For EUR players, this update was mandatory for online play. If you are still playing on a vanilla cartridge (Ver. 1.0), you are missing the following core additions:
While some homebrew tools or ROM archives list this as "v15," the official Nintendo version number is Ver. 1.5 . The "v15" naming convention stems from the internal title ID (0004000000086400) revision history. Regardless of the label, the content is identical. animal crossing new leaf update v15 3ds eur