I try to install a new Python version (3.8) using conda.

!wget -O mini.sh https://repo.anaconda.com/miniconda/Miniconda3-py38_4.8.2-Linux-x86_64.sh
!chmod +x mini.sh
!bash ./mini.sh -b -f -p /usr/local

This works fine. I can call !python script.py to run a 3.8 version.

So, I try my luck with installing another jupyter kernel with Python 3.8 kernel.

!conda install -q -y --prefix /usr/local jupyter
!python -m ipykernel install --name "py38" --user

I check that the kernel is installed.

!jupyter kernelspec list

Then I download the notebook down. Open a text editor to change the kernel specification to

"kernelspec": {
  "name": "py38",
  "display_name": "Python 3.8"
}

This is the same trick that works before, with Javascript, Java, and Golang.

I then upload the edited notebook to Google Drive. Open the notebook in Google Colab. It cannot find the py38 kernel, so it use normal python3 kernel. I run all these cell again.

!wget -O mini.sh https://repo.anaconda.com/miniconda/Miniconda3-py38_4.8.2-Linux-x86_64.sh
!chmod +x mini.sh
!bash ./mini.sh -b -f -p /usr/local
!conda install -q -y --prefix /usr/local jupyter
!python -m ipykernel install --name "py38" --user

It install the Python 3.8 kernel like before. I refresh the browser, to let it connect to the new kernel, hoping it to work like JavaScript, Java, Golang kernel before.

It doesn't work. It cannot connect. Here's the notebook

Any help would be appreciated.

Update (Oct 2022)

Using @ngrislain's method, here's a notebook for Python 3.10 (3.11 also available)

I have found how to run Python 3.8 notebook on Colab.

• install Anaconda3
• add (fake) google.colab library
• start jupyterlab
• access it with ngrok

Here's the code

# install Anaconda3
!wget -qO ac.sh https://repo.anaconda.com/archive/Anaconda3-2020.07-Linux-x86_64.sh 
!bash ./ac.sh -b

# a fake google.colab library
!ln -s /usr/local/lib/python3.7/dist-packages/google \
       /root/anaconda3/lib/python3.8/site-packages/google

# start jupyterlab, which now has Python3 = 3.8
!nohup /root/anaconda3/bin/jupyter-lab --ip=0.0.0.0&

# access through ngrok, click the link
!pip install pyngrok -q
from pyngrok import ngrok
print(ngrok.connect(8888))

we can also use kora pip library

!pip install kora
import kora.install.py38