upgrade tensorflow on windows

I am not allowed to post comments, so I write this as an answer. The following worked for me:

pip install --user tensorflow --upgrade

Without "user" I got the error below, even when I run the prompt as Administrator:

ERROR: Could not install packages due to an EnvironmentError: [WinError 5] Access is denied: 
Consider using the `--user` option or check the permissions.

Upgrade it like a normal package:

If tensorflow is installed in a conda environment

activate your-conda-environment

then:

pip install pip --upgrade
pip install tensorflow --upgrade

This just worked for me.