First of all, check what’s in your ~/.jupyter/ folder. Some of the comments under the question mention you have a file named “MIGRATED” that contains only a timestamp.
If you are in this state, run the command: jupyter notebook --generate-config which will create a new file ~/.jupyter/jupyter_notebook_config.py. If you already have this file, you don’t need to run this command.
This file is where you put the code that will modify your IPython Notebook behavior. It’s a fully commented out (and well documented) file.
I have a related question open (How do I get IPython profile behavior from Jupyter 4.x?) that deals with attempting to set up multiple profiles, which is currently unanswered.