Posted by Rallaz on Jan 13, 2013; 10:36am
URL: https://forum.librecad.org/Incompatible-dxf-file-v-2-x-tp5707386p5707446.html

Hello Zmogas,

I found a solution for file dialog and KDE:

In KDE open "system settings" and select "File Associations"
then add a new  "file association" (Aka mime type)

In "Group" select image and in "Type name" write vnd.dxf

Select the new created mimetype (you can found on bottom of image group)
and in "General" tab add:
"Filename Patterns" => *.dxf
"Description" => DXFr12 vectorial image
"Application Preference Order" => at your discretion

Repeat all adding more  mimetype with name vnd.dxf
and changing "Description" for:
DXFr14 vectorial image
DXFv2000 vectorial image
DXFv2004 vectorial image
DXFv2007 vectorial image

To test open LC and save as... then open with an text editor and check $ACADVER var.
Values are:
AC1009 for r12, AC1014 for r14, AC1015 for 2000, AC1018 for 2004 & AC1021 for 2007