I currently have installed pip 8.1.2.
So I want to upgrade it to the latest version (9.0.1) and I execute:
sudo pip install --upgrade pip
Collectin
Had a similar issue with pip not wishing to upgrade, though I'm not keen on replacing the package manager's version and as I'm always adding the --user option on installations via pip I figured "what's the harm?" in doing the same with pip on itself.
pip install --user --upgrade pip
It'll only work for one user but for some use cases that is just peachy.