Error 50 in drawing header in AutoDesk Viewer about librecad HOT 2 OPEN

Have you solved it?

from librecad.

This is hard to evaluate, if this is an us or them problem.

It turned out, that Autodesk software throws Error 50 in drawing header on line 930 for the file in question. The line number may vary for other files.
Searching for this error shows a lot of similar results on Autodesk forums.

The original file is AC1032 (ACAD 2018), LibreCAD saved in format AC1021 (ACAD 2007).
The only issue in line 930 is the value of the variable $XCLIPFRAME, which is 2.
All DXF references, 2007 (R21) and 2018 (R32), even the latest 2023 (R37) list only 0 and 1 as valid values.
Thus the error in Autodesk Viewer is raised by the value 2 of header variable $XCLIPFRAME.
Changing the value in line 930 to 1 opens the LibreCAD file in Autodesk Viewer.

LibreCAD just red the value 2 from the original file, and saved it with the same value in its latest format. There is no hint in DXF references about value 2 for variable $XCLIPFRAME.

So the questions are:

• What is the source of 77771_ORIG.dxf?
• Why does Autodesk Viewer accept this value for DXF format AC1032 but not for AC1021?

I can't see any reliable solution from LibreCAD to solve this.
Especially, when the official DXF reference does not document this value 2.
Because Autodesk Viewer opens the original file in DXF 2018 format, it might be a hidden feature, added after DXF 2007. But then they should have a fallback solution to handle this value for older formats.

from librecad.