The Keitai tamagotchi (or K-Tama) was released in 2004 and is recognizable by its antenna on the left. It adds an internal currency system to the game (Gotchi points), new characters, new mini-games etc.
A year later a re-release came out: The tamagotchi Akai. In 2005 the Hanerutchi version in partnership with the Haneru No Tobira show was unveiled, then in 2006 the Tamagotchi Connection V3 was released with a similar design and similar concepts.