Only if you're using version specific features.

What happens when python 3.8 comes out? Everybody needs to go into your script to change the hashbang every time a new release comes?

you can just hashbang to python3 which is a symlink to whichever python3.X the user has.

If your code won’t work for older versions you can make an explicit check that the version of python is greater than whatever you need.