Pipenv: Setup.py of pipenv fails with latest version (11.1.5)

[anbreww]

Environment

1. OS Type : python docker image (running from bitbucket pipeline)
2. Python version: 3.5.1
3. Pipenv version: 11.1.5

Expected result

Install pipenv using pip install pipenv --upgrade and start using pipenv

Actual result

pip install pipenv --upgrade
Collecting pipenv
  Downloading pipenv-11.1.5.tar.gz (4.1MB)
    Complete output from command python setup.py egg_info:
    error in pipenv setup command: 'install_requires' must be a string or list of strings containing valid project/version requirement specifiers; Expected version spec in pathlib;python_version<"3.4" at ;python_version<"3.4"

Steps to replicate

Install docker image python:3.5.1
pip install --upgrade pip
# on the image, this installs pip 8.1.2. I get the same result with the older version 7.1.2. This build pipeline worked fine until a few hours ago.
pip install pipenv --upgrade

[techalchemy]

Upgrade your version of setuptools, we use the modern syntax for conditional dependencies

[anbreww]

Thanks, upgrading setuptools fixed the issue!