It's not that he had a different design, it's just that characters occasionally get redrawn because the old art was very low res and makes their sprites blurry (for example, Khenbish just got his sprites updated in the last patch). In Asterion's bashful expression he used to have a blush in the older version but in one of the redraws it was removed. The rest is essentially the same.
The only one I've seen so far have an actual design change was Kota, as he is very different in the new version.