Thank you for the heads up!
Dropbox has recently changed the way its OAuth2 authentication works.
In the past you'd get a single access token that never expires and gives you full access to any operation in Dropbox.
Under the new scheme you get an access token with a short expiration time and a refresh token. The access token has a limited scope i.e. it only allows specific operations. When the authentication token expires you exchange the refresh token with a new pair of access and refresh token.
Since the old method is going away "soon" (there was no hard cut-off date when Dropbox notified us of the change) we changed our server-side code to use the new method with the scoped, expiring access token and refresh token.
The code for the regular Dropbox has been updated to use the refresh token. The code for Dropbox for Business, however, is missing a change in one place. I am currently working on fixing that. The fix will be included in the update we plan for the beginning of March, in about a week's time.
Nicholas K. Dionysopoulos
Lead Developer and Director
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