I just upgraded my IPython version to 5 and one thing that I'm missing is my vi mode binding. When I read the changelog, they now replace readline with prompt_toolkit a pure python interactive command line prompt. This is very nice because it supports all platform that python supports.

So to bring back your vi binding, you need to do this.

ipython profile create

This will create a default profile where you can change your IPython configuration.

Edit this file

vim ~/.ipython/profile_default/ipython_config.py

Uncomment this line

c.TerminalInteractiveShell.editing_mode = 'vi'

When starting IPython, you now have you vi binding back.