I am currently working on a project where I am drafting polygons (as closed polylines) in AutoCAD 2015, using ArcGIS for AutoCAD to create a feature class out of these new polygons, then using ArcGIS to open the CAD-built feature class and converting them into a geodatabase. However, the CAD-created feature classes do not show up in ArcGIS unless I first save the DWG file back into 2010 format or earlier. Would anyone happen to know why this is the case?