Makes no difference what is printed on them....it's going to be a matter of changing the way of thinking that the cards and the bands hold any pertinent data at all. What they have is a RFID chip that has a unique number that accesses YOUR My Disney Experience profile. If you have a resort stay and it's linked to MDX you can use any of the bands or cards that are active and assigned to you on MDX (the ones you want to be able to open the resort door should be used to open that door as soon as you can - if you have two, open the door twice, once with each item). If you have an active band or card that is assigned to your MDX account, they should be able to read any information on your MDX profile. They will not be deactivated unless YOU deactivate them.
Some of the old cards will also have a magnetic strip which was the old way of encoding information on the card (which was then read by swiping the strip). You're not going to need that anymore. it's all going to be done via that RFID chip.
I can use my annual pass card to open my resort door so long as I have a current stay linked to MDX. I could likely use an old KTTW card to enter the park as long as it is active and linked to the same profile. Haven't tried it, but that's how it's supposed to work.
