The main change in this version is an improvement in antialiased line segments, introduced in version 2.1.3.1. This feature is definitely not suitable for large (many thousands of points) data sets, because it is slow and also because it just doesn't look very good with line segments that are only 1 or 2 pixels long. But for smaller data sets you can produce a more attractive graph, which might be important if you typically copy/paste DPlot graphs into PowerPoint or other presentation package as bitmaps. Antialiasing is applied on displays and saved/copied bitmaps only; not to printed images (because printers have a high enough resolution that antialiasing is generally not needed) or metafiles, because it is essentially a dot-by-dot operation not applicable to vector images.
Example:
Normal lines, no antialiasing:
Version 2.1.3.1 antialiasing:
Version 2.1.3.2 antialiasing:
