Dropbox announced last year that the v1 API was deprecated and would be taken offline. If you are still using it, you should move to the v2 API as soon as possible.
Ensembles 2 has had support for Dropbox API v2 for some time. Use the appropriate backend class. The Idiomatic example shows how to set it up in detail.
Ensembles 1 now has support for Dropbox API v2 too. We have back ported it, and it is included in release 1.7.