How to install `qiskit==0.2x.x`

on x86_64 or AMD64 (Windows/MacOS/Linux)

install anaconda and create environment as usual. Python version should be 3.8!
```
conda create -n qiskit-2x python=3.8
conda activate qiskit-2x
```
Now you can downgrade to older versions of qiskit from source, or with pip
```
pip install -U qiskit==0.2x.x
```

For this lectures, you would need the followings

pip install matplotlib==3.4.3 ipywidgets ipykernel pylatexenc seaborn

Not allowed