Hi all, like threatened, we are introducing release candidates. The first of which is just released into the wild. If you want to live on the bleeding edge with your CI you can replace the tox installation invocation with ... pip install --pre -U tox ... and you will also use release candidates. Using this if you don't mind having a slightly higher risk of breaking your build due to a porblem with a new tox relase. This can really help us to catch problems early before they reach the masses. For details about the release please see: https://pypi.org/project/tox/2.8.0rc1/ - the relevant section is currently marked as "not released yet" - this was an oversight: in future releases and rcs this will contain the correct version number again. For internal details about the release have a look at the issue on GH: https://github.com/tox-dev/tox/issues/538 Happy testing, Oliver