[Zope] Version Control in CMF/Plone?

A feature I mis in Zope/CMF/Plone is version control of documents. With this I mean for example that authors can (minimally) view and revert to previous versions of documents. This as opposed to the back-end Revision Manager product which allows versioning of Zope objects in CVS. I've found a reference to a project to integrate version control in Zope. http://dev.zope.org/Wikis/DevSite/Projects/ZopeVersionControl/FrontPage. Is it known what the status is of this endavour? Regards, Iwan van der Kleyn