I explain briefly what are the differences between each Tamagotchi Connection / Connexion model!

Timestamps:
0:00 Tamagotchi Connection V1
1:20 Tamagotchi Connection V2
2:32 Tamagotchi Connection V3 / Keitai
4:15 Tamagotchi Connection V4 / Entama
7:05 Tamagotchi Connection V5 / Familitchi
9:18 Tamagotchi Connection V6 / Music Star
11:51 Tama-Go

Other Connection models not featured here but also notable are the V4.5, V5.5, and other variants such as Oden-kun.