プチコン (Puchikon) was only released in Japan. This version didn't have BGM, (I think) and didn't have the QR Code scanning function. You had to program it to have it.
プチコンmkII (Puchikon mkII, known in North America as Petit Computer) was released in Japan and North America this included BGM and the QR Code scanning function.
Finally プチコン3号 (Puchikon 3 [san] gou) has currently only been released in Japan, but SmileBoom is trying to release this in North America and Europe sometime in 2015 (hopefully.)
I'm just clearing up the confusion.
By the way, DИ, how were you able to post a comment on the main page of this wiki? I can't do it. It might be because it's not out where I live, so, how did you do it? Do you have a Japanese Wii U/(New) 3DS?