Of course not. Consider the answer as No", but take notion of what kind of novelties are really adding new types of content to a drawing (like the new Freeform Gradient points and lines), and which new features are actually just new approaches to achieve some result in a different way (like the Shaper Tool).
New types of content are difficult (or just impossible) to read back into older versions of Illustrator. While new approaches are just a workflow difference, they don't show up in the drawing, so the result is also possible and still editable in older versions. However, some new approaches are really very easy and smart, like Puppet Warp ! Wouldn't want to miss out on that one...
Oorspronkelijk geplaatst op Quora: Does Adobe illustrator CS6 have all features of Adobe illustrator CC 2019?"