I can "save world to device" which allows us to save progress in a world which is good. Swapping a world out using "Replace World" will work but the "Uploading World" dialogue does not show progress.

Example: A world save that is 18.2MB will sit at 0.00MB progress until the upload is complete. I have an application that shows me that data is being sent over my internet connection so I waited and the upload completed and the world was playable.

This issue is not a big problem if you're aware of what is occurring but when I was uploading a large world save, until I was monitoring my internet traffic I had no idea whether the world was uploading or whether the program had frozen.