pip install -r requirements.txt -c constraints.txt You can also, thanks to the weird way requirements.txt works, put the line "-c constraints.txt" in requireme

pip install -r requirements.txt -c constraints.txt You can also, thanks to the weird way requirements.txt works, put the line "-c constraints.txt" in requirements.txt. In that case you don't have to specify it when you run pip. That should apply the constraints when installing packages. I don't know if there's also a way to validate what's already installed.