Where can I find the documentation for Sage 9? I only see the latest on Documentation | Docs | Roots and I assume it’s for 10.x
They used to be https://roots.io/docs/sage/9.x/installation/ but that is redirecting or is now not versioned the way it was.
The ecosystem dropdown from that page you sent seems to link there only, and I don’t see a 10.x in the versions dropdown.
Sage 10 docs are here Installation | Sage Docs | Roots
All of the docs are in a GitHub repo. It doesn’t look like docs for old versions of the software are available on the site, but you can find them in the repo. The docs were recently reorganized, so this is the repo at the comment just before that re-org: GitHub - roots/docs at 35c61e28b018be08c182629856dff2773d92c9eb