It’s very subtle, but I think you succeeded in making Littlefoot’s face look older.

And I see you added the stripe on the underside of his tail, too. I might suggest making it a little longer (in adult longnecks it extends at least halfway down the tail), and I think the tail itself could be stand to be even narrower, especially the area between the tip and the portion you already changed.
Cera’s face, too, is subtly improved. She does look younger. I admit I had to look at both the old and new versions of Cera in quick succession to notice the alteration to her tail,

but that looks better as well. And it looks like you knew exactly what I was talking about with her feet. They look much, much better.

I’d say they’re close to perfect. The one thing I might possibly change is the innermost toe on her left front foot, which should maybe be shortened a little bit from beneath in order to match the inner toe on her right front foot, which is largely hidden behind the others. (My fault for not thinking to point that out before.

)
Every change you made to Petrie is a definite improvement,

the hands, head, beak, chest, and stomach most noticeably. I particularly like how you changed his fingers. By the way, what I liked about his neck ruff in the first picture you made of him was the fact that it curved and tapered downward slightly at the pointed part, with a more prominent line above that point connecting to his neck, that gave it a puffy appearance. (Another thing I should have specified earlier.

)
Are you planning to do new older versions of Ruby, Chomper, Ducky, and/or Spike?
