Fix the version mix
There is Python 2 and Python 3 and the former comes with fail2ban version 0.9.6 and the latter with 0.9.3 - newer Python but older app.
A way to fix this is to use the later fail2ban with Python 2 and we get there by copying the new client to the /usr/bin directory:
sudo cp /usr/local/bin/fail2ban-* /usr/bin
sudo service fail2ban restart