Dropbox changes?

Hello. I have used this plugin for several years with league results linked to excel files in dropbox. I am getting ready for the new season and found that all of the previous links do not work. They give a file not found error.

I have confirmed the files are still on dropbox in the same place. I copied a link and verified it is the same as the current link that is not working.

It seems that something may have changed with dropbox and the API. The instructions I found for the plugin differ from what Dropbox shows now. Are there updated instructions I should be following?

On another note I no longer see the add document button in the graphical interface. Where did that go with the latest wordpress?

Thanks