I found one game that can update a Japanese 3DS to version 4+ on this website, (http://www.eurasia.nu/wiki/index.php/3DS_Games_with_firmware_updates_in_the_4.1_-_4.5_range), which is Project X Zone.
Are there any other games that are capable of upgrading it to the 4+ range?
Are there any other games that are capable of upgrading it to the 4+ range?