python - You are using pip version 8.1.1, however version 21.2.3 is available. You should consider upgrading via the 'pip install --upgrade pip' command - Stack Overflow
Pip Upgrade – And How to Update Pip and Python
How to Upgrade PIP Package to Latest Version [Update PIP]
How to Install Pip on Mac {Step-By-Step Guide} | phoenixNAP KB
pip and conda to install and upgrade Python packages