There is a good explanation why you should pin your packages. And there is a set of tools to automate this process: 1. PipEnv https://docs.pipenv.org/ 2. pip-compile-multi https://pypi.python.org/pypi/pip-compile-multi 3. pip-tools https://github.com/jazzband/pip-tools 4. pyup https://pyup.io/ Personally I use pip-compile-multi in all of my projects, because I fallen into this trap every time I didn't. But whenever I talk about it to other developers no one seems to care. What do you think, is running a complex project without pinned dependencies a viable idea?