What is the difference between some tamagotchi shells

Hi ^_^

i recently rediscovered tamagotchis again and have bought quite a few now. I’ve been researching for a while now but cannot find the answer anywhere for this. 

(From my version 1/2 tamagotchis) I currently have two v2 tamagotchis and a v1. I’ve noticed that both my v2 tamagotchis just say tamagotchi at the top of my shell  whereas  the top where as my v1 says tamagotchi connection on the shell. 

I’ve searched on project tamashell to see why there is a difference but both v1 and v2 have some shells with just tamagotchi on and some with tamagotchi connection. Does anyone know why some do and some don’t?

If it says just tamagotchi, that means it’s UK/European version.

The ones where it says tamagotchi connections, it’s US version. 

iTamannadi said:

If it says just tamagotchi, that means it’s UK/European version.

The ones where it says tamagotchi connections, it’s US version. 

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There are also European/Asian variants which have "connexion" on them, and I believe some of the Oceania shells also have "connection" printed on them.

Eggiweg said:

There are also European/Asian variants which have "connexion" on them, and I believe some of the Oceania shells also have "connection" printed on them.

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This is why I’m confused, I thought it might be because some were release in one area of the world and the ones that say connection were released in another but if the European/Asian/other areas still sometimes have these variations in shells I’m still wondering why 

https://tcrf.net/Tamagotchi_Connection

Here's a list of differences which might be interesting to you.