Downgrading Pillow usando pip

Question

Eu preciso executar um aplicativo antigo e, para isso, preciso de uma versão mais antiga do Pillow do que a atual instalada. No entanto, pip não quer me deixar desinstalá-lo nem instalar uma versão mais antiga.

    charlie@charlie / $ sudo pip uninstall Pillow
The directory '/home/charlie/.cache/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Not uninstalling pillow at /usr/lib/python2.7/dist-packages, outside environment /usr
The directory '/home/charlie/.cache/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
You are using pip version 8.1.1, however version 8.1.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

Posso forçar isso de alguma forma? "Sudo -H" não faz nada ..