wotlk NEW and OLD models client differences

Hello dear Warmane community,
I have a feeling, that this question has been already asked somewhere and I honestly did my research, but I found nothing. I'd like to know whether players with NEW wotlk models are on the same servers as players with OLD wotlk models client. I mean, can I play together with a friend who downloaded new models version, if I play with the OLD models?
I just want to be 100% sure, sry if this question is stupid
Thanks in advance!

Yes. The difference with the new client is that it only has updated models and things look "prettier"