Are serialized decks still used?

Are serialized forge.Deck instances (the old deck format) still in active use, or can we assume that they have all been converted to the new text-based format?
I am trying to move quest deck metadata (deck name, description, difficulty, etc.) into the .dck files so that code changes are no longer necessary to add quest opponents. This task is going to be much more painful if serialization compatibility is still necessary.
I am trying to move quest deck metadata (deck name, description, difficulty, etc.) into the .dck files so that code changes are no longer necessary to add quest opponents. This task is going to be much more painful if serialization compatibility is still necessary.