So, if I understand then (and I may not because I'm new to this) you have to start a new game even if you're updating? (editing this to clarify because what I was asking sounded way more stupid than intended. I get that I have to start a new game but trying to help a friend and hoping she doesn't have to start all over.)
Also I was following download instructions from the site and deleted the prefab file originally - when the game tried to load, a lot of the wall of red/yellow was related to not having the prefabs?