Problem

I ran the IPython Notebook server in a directory containing a .ipynb notebook file:

$ ipython notebook

It opened the URL http://127.0.0.1:8888 in my browser. The notebook file was listed in the webpage. I clicked it to load it and got this error:

Error loading notebook

Unreadable Notebook: Unsupported JSON
nbformat version 4 (supported version: 3)

Solution

This error is caused due to opening a notebook created with a newer IPython on a computer with an older IPython. On my computer, I was using IPython installed from Ubuntu repositories, which is ancient.

I first uninstalled it:

$ sudo apt remove ipython

I installed the latest IPython from the Python Package Index:

$ sudo pip install ipython

The installation was successful, but on running IPython it complained about many other programs. I installed the libraries it complained about:

$ sudo apt install python-zmq python-jinja2 python-jsonschema

IPython Notebook ran correctly and I was able to open the notebook after this! 🙂

Tried with: IPython 3.2 and Ubuntu 14.04