Hello,
Regarding the error message:
You are not on the latest version of Anki. You can download it here: https://apps.ankiweb.net/. After downloading, simply run the downloaded file to update your application.
Regarding all of the cards being in one grouping:
This is actually how the deck is intended to be. All of the cards are in one single deck, but they are organized by tags. This is due to how Anki works and how it handles a large amount of subdecks versus tags.
The recommended workflow for studying is to keep all cards suspended and then unsuspend only the tags you are currently studying. When you finish those, you can unsuspend the next tag, and so on. This tutorial can help you understand how to unsuspend cards by tag: How to Get Started Studying with Anki. This tutorial is for the Anki step deck, but you can just follow the same thing for the MCAT deck.
As you can see, the tags are segmented by study resource.
