Can I upload a new version without previously deleting ancient version

[metulburr]

But what happens if I upload new version without previouslly deleting ancient version ?

Nothing you would just install another version. The older ones would just sit there. On one of my systems, i still have 3.4, 3.5, and 3.6 on it just because i never bothered to removed them. You just need to make sure to update the inerpreter path for any IDE you use to the interpreter you wish to use.

To remove old ones, if you compiled from source, go to the directory and run make uninstall

If you installed it via your package manager, then you would have to use that, if ubuntu

sudo apt-get remove python3.3