[R] Version Management for Classes as in Green Book sec 7.4?

[Dr. Peter Ruckdeschel]

Just a simple question:

Is there any project going on in the R-Community
 implementing  version management for classes as discussed
in  the ``/Green Book/'',  section 7.4 ?

I would really appreciate this feature, above all more or less 
automatically
updating objects of an older class definition.

Thank you already.
-- 
Peter Ruckdeschel