The version number is based on the number of placemarks I have added.
If there is a significant addition in placemarks, the digit is increased.
If it is minor correction or addition, the decimal point is increased
From Ver3.3 to Ver4.0, over 350 placemarks and new categroies were added.
After Ver4.0, I have made some minor changes and additions, so the increment is on the decimal point.
I hope the above is in line with the norm for version naming.

If it is not the case, please feel free to let me know.