The version we've been specifying for mypy is version 0.580, which is very old and has been causing version conflicts with modules as well as holding some modules back that could be upgraded. Also, since the version is so old, there is no longer a wheel for it, which means anyone installing it would need to compile the C extension to install it. If that person is using asdf or pyenv for their Python installation, that will likely fail. A solution would be to require a compatible version instead, which will resolve these issues.