When you save a drawing to a previous release file format, not all objects and properties will be supported. You can do one of the following:
- Save the drawing to the current release format: All objects and properties will be saved correctly, but the drawing may become incompatible with earlier releases.
- Save the drawing as AutoCAD-only objects.
To view AutoCAD objects in a previous release, verify that the latest Object Enabler is installed, as available on http://www.autodesk.com/enablers.
- Save the drawing to a previous version with Proxy Graphics. If you open the drawing in the previous version, you can view AEC objects as Proxy Graphics, but cannot edit them.