User blog comment:RoyallyBella/Official Season 7 discussion blog/@comment-24929396-20141217111807/@comment-25749471-20141218075542

Seasons 1, 2 and 3 are all hand drawn. Season 4 and beyond are 2D. If you watch the end of season 3 and then go straight to season 4, you'll notice a distinct difference in the way the characters move. 2D animation makes the movements a lot smoother.