Technical diagnosis
This message usually means the file was saved in a newer AutoCAD release than the one installed on your current machine. Closed creative and engineering formats often cannot be opened backwards without a controlled downsave or exchange export.
VersionFixer route
Upload the DWG/DXF file, let VersionFixer identify the format, then choose AutoCAD 2007, 2010, 2013, 2018 or another requested DWG version. The job is queued for the right worker and the result appears in your account when ready.
Upload the file now