Long gone are the days when Digimon tried to compete with Pokemon. Regardless of who won that war, fond memories exist for both. When a new Digimon anime that would feature the original cast but older was announced, I think it’s safe to say that many fans rejoiced at being able to see their favorite characters again. Anyone who’s seen the previews for Digimon Adventure tri., however, will notice that, even if the characters themselves are recognizable, their designs are significantly different compared to the original anime in a way that can’t just be explained by them being in high school.
Digimon had a typical yet still distinct enough style where characters had big heads, big eyes, and big hands that it carried through multiple series. In many ways it was unmistakably the way a kids’ anime was expected to look. Digimon Adventure Tri, in contrast, not only has characters with more realistic human proportions but also has a kind of looseness to the art that to an extent resembles Hosoda Mamoru’s famous Digimon films such as Our War Game. They could have easily mimicked the original style or even refined it to look more mature, so obviously this change is deliberate, but I think this change is particularly fueled by the fact that Digimon Adventure tri. is targeting the audience that watched the original Digimon Adventure all those years ago.
Essentially, I believe that the new character designs and general appearance of Digimon Adventure tri. are a way to show how the series itself has grown up just like the people who first watched Digimon Adventure. The audience has changed, the world has changed, and so too has Digimon evolved into something else. If anything, it’s grown up just a bit more slowly, as the kids who watched it then are probably in their 20s at this point, and they’re going to see Taichi, Yamato, and the rest stepping forward into adulthood.