Nintendo has announced that Nintendo 3DS Firmware 9.7.0-25 is available to download. The firmware "further improvements to overall system stability and other minor adjustments have been made to enhance the user experience." The official Japanese Pokémon website has also confirmed the firmware fixes the crashing issue for
Pokémon Rumble World on Nintendo 3DS XL and the New Nintendo 3DS. It is recommended all Nintendo 3DS owners update to the latest firmware.
Nintendo of America also tweeted a new password for
Pokémon Rumble World to unlock Togepi for North American games. The password is
04730723.
We have added a passwords page and will update it as new codes officially become available.
Sources:
https://twitter.com/NintendoAmerica/status/590299080384872449,
http://www.pokemon.co.jp/info/2015/04/150421_at01.html and
http://en-americas-support.nintendo.com/app/answers/detail/a_id/667/~/information-on-recent-system-and-feature-updates