Version 4.1.8 had a fix for a crash during boolean operations that would occur if colinear points were present. This was due to Import DXF not cleaning up colinear points.
Both import and export DXF have had various fixes; export DXF outputs paths as polygons now. Import DXF rounds to database units; previously it truncated, resulting in shapes with coordinates e.g. 3.999um.
Dynamic highlight and selection has been improved; if dynamic highlight is on then the last object/edge/vertex highlighted will be selected on LMB click. Dynamic highlight latency time has been reduced from 50mS to 10mS.
Deselecting objects using the ctrl key modifier now works correctly if gravity is enabled or not.
If gravity is enabled, clicking anywhere inside an object will select that object; previously you had to click within the gravity distance of the object's edges to select it.