As has been pointed out on the Discord, on Mastodon, and on GitHub, the Idris website is severely out of date. It has been on the todo-list for a while, but I'm now actively working on bringing it up to speed, as well as making it easier to maintain going forward.
In the meantime, a banner has been added to the front and download pages, pointing visitors to more current resources (pack and the Idris2 GitHub Repository), which should hopefully help reduce confusion. And on the admin side, the GitHub Pages workflow is no longer bitrotted and the site builds again; that should help with things.
We're on it!