hopefully this catches a fair number of downstream developers. Matplotlib’s canonical root is https://matplotlib.org/stable/ now. https://matplotlib.org/ still works, as do the versioned prefixes (i.e. https://matplotlib.org/3.2.0/), and the dev branch https://matplotlib.org/devdocs/index.html. However, the toplevel root is now a bunch of redirects, so link checkers will be upset. If you use inter-sphinx to build docs, that should also be changed. See and discuss at https://discourse.matplotlib.org/t/canonical-documentation-have-moved/21863 and of course please report any issues and we will try and fix.