With C4R, there is no way to access a model (assuming you are invited to the project) unless you are in the correct version or Revit.
So if I have a C4R project that hold Revit 2015 model files, then you must use Revit 2015 to access the model files, if I try to use any other version of Revit (Revit 2016, 2017…), I still do not have access to the model files, even if I try to access the model through Revit’s Manage Models, it will only show models for that version of Revit
I could go through the C4R project site and download the model files from there, but this will only give me access to models that someone has published, so I may not get the latest models (they could be month old).
With upgrading of Revit versions, If one is one Revit 2021, and I need to get access to my Revit 2015 C4R models, if I do not have Revit 2015, I cannot get access to the latest models to upgrade them to Revit 2021, so I cannot upgrade them to the latest versions of Revit.
If would be great if there was an admin area that was version agnostic to access the C4R model files, similar to the Manage Models interface through Revit, but again would be version agnostic.
As we move forward with version of Revit, our c4r project model files will become more and more inaccessible from the cloud, there needs to be a better management solution that gives us more flexibility in accessing our model files from the c4r service