Hello @James_Garrett, I merged your post with the relevant thread.
We’ve built a new improved editor, called Prezi Present, that brings together the best features of Classic and Next. You’re now able to convert your Classic presentations and edit them through there, I’d recommend you to check this article on how to do so.
Please, note that you will only need to convert the presentations you need to further edit, if you just want to present them you won’t need to do so
Hope this could help!