The notebooks in the BigBang examples directory have been version 3 since the project started.

In the most recent version of IPython, the notebooks have been updated to v4 to include (among other things?) the language-agnostic Jupyter branding.

I'm going to update these notebooks in a commit soon, as per this issue:

https://github.com/sbenthall/bigbang/issues/174

Please update your IPython packages in your Python environment so that you can use the new notebooks.

Thanks,

Seb