Hi Christine ~
I am excited to see that you're planning ahead! Planning is always super fun for me and it helps to keep me calm (at least a little more calm) until my trip.
As of now, backpacks are absolutely allowed inside the theme parks. I am a backpack kind of gal and I always take my backpack into the theme parks when I'm visiting the Walt Disney World Resort. Even when I am traveling without my boys, I still take my backpack. In fact, I did that very thing just last week. I really like having something to carry everything I need including water bottles that allows me to traverse the parks hands free. They do not permit suitcases, coolers or backpacks (with or without wheels) that are larger than 24" (61 cm) long x 15" (38 cm) wide x 18" (46 cm) high. Just make sure your backpack is within those measurements.
Keep in mind that all bags will be searched prior to entering the theme parks. It will speed up the process if you already have all of the zippers on your backpack open before you get to the security checkpoint. If you have any smaller bags (i.e., camera case, make-up bag, etc.) inside your backpack, you should go ahead and have those out and open as well. I put everything in clear Ziplocs. That also helps speed up the process and protects anything I don't want to get wet in the event of rain or on water rides.
Policies can indeed change but as of now you are allowed to bring in backpacks. It looks like you may not be traveling until the fall of next year. Before you head out on your trip, make sure you check the official Walt Disney World website for the most up-to-date
list of personal items that are not permitted in the theme parks. You are also welcome to check back with us as well.
Please feel free to visit us again with all of your planning questions. We are hEAR for you!
Wishing you minnie magical memories :-) Allison V.