I was trying to download the server live iso (39400), but the link at the Downloads page is not working. It would be nice to have some links to older releases as well, so at least something can be tried out.
Have you tried https://cdn.download.clearlinux.org/releases/39400/clear/clear-39400-live-server.iso (on that page)? It doesn’t work here.
Our build process broke for the live server iso between builds 39240 and 39520. See Download link clear-39400-live-server.iso doesn't work
We do keep an extensive history of past builds available.
No, the last one I used for an installation was about 389xx and that was a desktop version.