[Zope] Owner role in zope 2.1.3

I have a zope powered educational application that allows authenticated users to create subfolders and to upload documents of various types. In the 2.0.0 version of my application local roles of owner were attached to these user created folders and documents, featuring the user responsible. In the 2.1.3 version of zope the owner local role is only created in documents and not in user created folders. Bug or feature? The behaviour of the application depends to some extent on ownership. Or did I miss something while upgrading? I just copied data.fs.* cb