My pip version was old, really old. 1.5.6 When I installed my virtual environment it just worked, so I didn’t question. Lesson learned! Here is what I did in case it helps someone else…
In the virtual environment, I installed pip as described in the docs:
https://pip.pypa.io/en/stable/installing.html
python get-pip.py This upgraded me to pip 6.1.1
pip install django-filter
pip freeze > requirements.txt
Reading requirements.txt showed I had
django-filter==0.9.2
django-filters==0.1.0
So I uninstalled the older version with pip uninstall django-filters
notice the s on the older version but not on the new one
Really basic stuff but it really tripped me up. Thanks to anyone who took time to look into this!