The oldest Tamagotchi character I've ever heard of was Aaron, raised on a V3 by Kyliesmum. He died at age 145, on Aug 7, 2006. You can read all about it here: https://www.blogagotchi.com/kyliesmum2/
Tamagotchis WILL die of old age. No tamagotchi can live "forever". This may seem hard to believe since I have no proof but I just know that eventually, all old tamagotchis will die of old age.
thx. cuz i was thinking about just lettin my tama, bonny, grow until she was rele rele old or until she found someone to connect with, cuz i heard oldies can't see the matchmaker. But I don't want to risk her life
I raised my tama til it was ova 99! it was a adult mametchi which i belive is the healthest character she transformed into the matchmaker tama! but avventually i got bored of havin the same character so i reste her her name was Heidi bye Heidi!