It looks alright with dithering even with such low amount of colors I also keep hearing griping that the color dithering is all patent encumbered and/or that

It looks alright with dithering even with such low amount of colors I also keep hearing griping that the color dithering is all patent encumbered and/or that there's few open-source options available. Bother. Huh, is it? I am using python to dither images just fine