Great, thanks @kolodzie for getting back to this. I totally understand the fact that you prefer a careful evaluation. In that case I will close it and for now we go with explicitly defining the versions in our repo at his point (which is indeed easy enough).
Maybe it could be helpful to simply add a few words to the README just so that people are aware that they might need to pass specific versions explicitly.
Related to ticket https://cern.service-now.com/service-portal?id=ticket&table=incident&sys_id=fbaf5cbd97c90a1081ef33f71153affd
We had issues and the CI stopped working for me about a week ago.
Bumping the versions (some of them looked indeed relatively old), fixed it for me.
But maybe there is a specific reason for keeping the versions you have at the moment?
Benedikt Voelkel (31051ff5) at 25 Mar 13:01
Bump default versions of MkDocs tools