hello folks, Do you remember my mail explaining I was working on an evolution of class/object management for class properties deletion and class inheritance with backward compatibility? Here is the status of this study: My idea around class versioning seems to be working. Now I can delete class properties and keep managing older and newer class instances. It also doesn't seem to modify the existing behavior for already embedded classes/docs/objects in XWiki enterprise. I have implemented a draft based on a 2weeks old core. Basically, I had to modify the core code but I have always tried not to modify any existing logic, as little code as possible and to use existing features as much as possible. Naturally, I must implement and perform some more tests to be sure there is no hidden critical problem. I still have to study precisely the custommapping issue... Finally, I'm currently implementing the inheritance mechanism... As it would be too long to explain everything here and as I prefer that you see it with your own eyes, I will try asap to mount a demo environment with an explanation of the why/what/how I did this... Best regards Pascal