Howdy, Steven! Thanks for bringing your question to planDisney!
I'm glad you are keeping up with all the Disneyland Resort news! You are correct that Disney FASTPASS and MaxPass have been retired and soon
Disney Genie and Disney Genie+ will replace them. We don't yet know the exact date that these services will launch, but since I see that you are planning to visit at the end of December, there is a pretty good chance you'll be able to use these features during your trip.
If you already purchased your theme park tickets, you will be able to add on Disney Genie+ for $20 per day, per ticket. You will make this purchase each day you are in the parks on the
Disneyland app. If you plan to take advantage of the individual attraction purchase option which allows you to select up to two return times per day for Star Wars: Rise of the Resistance, WEB SLINGERS: A Spider-Man Adventure, or Radiator Springs Racers, you will also make those purchases daily in the Disneyland app.
I hope you have a magical time at the Happiest Place on Earth!
-Linda