The original author has a habit of abandoning software projects after a while. But I think they managed to get it into the pypa docs (python packaging 'authority'), and so I guess someone has brought it back.
I believe, after some conflict with the community, the original author divested himself of all his F/OSS projects. This resulted in pipenv being donated to the pypa GitHub org. Since then, the project appears to be seeing sporadic development through community contributions.