Control the pip version in virtualenv

From reading the source of virtualenv, it looks like pip is installed from a source tarfile included with virtualenv. In virtualenv 1.10.1, it is pip-1.4.1.tar.gz in the site-packages/virtualenv_support directory (it gets setuptools from the same place). You could feasibly replace that archive to control the version; virtualenv.py, at least the version I have, doesn't care which version of pip is there:

    if not no_pip:        install_sdist('Pip', 'pip-*.tar.gz', py_executable, search_dirs)

You could also pass the --no-pip option and then install the version you want from source.

In virtualenv 1.11, it looks for a wheel file (e.g. pip-*.whl) instead of a tar.gz, but other than that it acts the same way (thanks @wim for the update).

For me, I just upgraded pip/virtualenv/virtualenvwrapper on my machine (not inside the virtualenv). Subsequently created virtualenvs had the updated version.

deactivatepip install --upgrade pip virtualenv virtualenvwrappermkvirtualenv ...

You cannot downgrade pip using pip, the solution is to install a specific version in your virtual environment:

virtualenv env -p python3.6 --no-pipsource env/bin/activatecurl https://bootstrap.pypa.io/get-pip.py -o get-pip.pypython get-pip.py pip==18.1

This will allow you to keep using --process-dependency-links that was removed in pip 19.