Thanks folks! The info is much appreciated.

Gwenolyn, I think it just needs one stone, since the tooltip says any pet.

I've been searching the nets for the last few days but haven't been able to answer this question. I'm wanting to know if it's retroactive because if it's not there are some pets I'd like to stop leveling until they can be upgraded. I copied a character to the PTR with a bunch of crated pets for batt...