Error loading notebook nbformat version 4 (supported version: 3)

ubuntu14.04

ref.
http://blog.csdn.net/elaine_bao/article/details/50675777

$ sudo apt remove ipython

$ sudo pip install ipython
or
$ sudo pip -proxy=http://xxx.xxx.xxx:8888/ install ipython
when an error occurs even if proxy is set on /etc/apt/apt.conf

$  sudo pip install jupyter

Then you can read ipython notebook successfully.
$ ipython notebook
...

Enjoy!