Hi Stefano, if you replace the file DXFExportTemplate.dxf (make a backup copy so you can restore the original if needed) with the attached version here that should make MoI write out an R12 DXF file.

One thing to watch out for though is that MoI will still write out a SPLINE entity in the DXF file if you set "Write curves as: Splines" or "Write curves as: Cubic splines" in the DXF export options dialog. That may confuse some importers because the SPLINE entity did not exist in AutoCAD R12, it was added in later versions. So if you do this use the setting "Write curves as: Polylines" in the DXF export options dialog.

- Michael