First one: WTF IS THIS, EWWWW- She also used to have green eyes (Shading is so trash).
Second one: Made the hair longer, and changed art style.
Third one: Changed color palette, ear shape, art style (again), and gave her yellowish eyes.
Forth and latest one: Gave her a little floating ahoge, and eye shadow? Not much has changed from the last one other than the art style.

So yeah, we can all agree that the first version is trash, and the latest one is better (I think).