Traingers/Trainer Cards

[BrianHa]

I remember there was some ruling change when D/p was released about trainers, trainer cards, stadiums, and supporters being different somehow.

Can someone explain this to me?

Thank you in advance

[PokePop]

Yes.
Trainers, Stadiums, and Supporters are now three different classes of cards.
That's the rule change.
Let us know if you have a question about a specific interaction that this would apply to.