How to migrate existing cloud storage services to Office 2016

Hi, 

me and my colleagues maintain an application that integrates as a cloud storage service into office 2013 as described in this article: https://msdn.microsoft.com/de-de/library/office/jj984352.aspx

Unfortunately, this is not working with office 2016 anymore. 

I've searched the web for hours but could not find a solution for making this work with Office 2016.
What can I do to solve this? 

Kind regards, 
Christian