This is the prosaically named Nekomusume from very long running anime franchise ゲゲゲの鬼太郎 / GeGeGe no Kitarou; the number indicates the season, and a movie version is also pictured.
The season start dates are as follows:
The direction character design has taken should leave no one in any doubt that we are now in the age of moe, and that successful titles had better be prepared to conform to the current aesthetic.
Nobody could blame enterprises and creators for responding to so clearly expressed market demands, but we must wonder at the state of mainstream (and of course even more so otaku) anime fandom for such visual styles to be preferred so overwhelmingly.
In this case the original was unlikely to missed, but in the case of A Certain Magical Index many consider the pre-moe version superior…