For LibreCAD 2 (in alpha stage but functional) the DXF read/write are fully rewrite
You can read DXF in ascii or binary and
You can write in R12, 2000, 2004 and, by default in 2007
and yes is compatible with ACAD.
if you save a file with the new DXF library and there are problems to open it with ACAD
open a bug report in :
http://sourceforge.net/tracker/?group_id=342582&atid=1433844