We’re removing installer support for Debian 8. It reached EOL upstream in 2018, but it still receives security updates until June of this year. But, something has changed upstream making Virtualmin installs fail, and since the OS is EOL and we don’t support installation on EOL operating systems, I’m just gonna remove it from the installer and our Grade A supported OS list rather than spend time resolving those issues.
Nobody should have been installing on Debian 8 at any point after June 2018 (really, even before that, as you should be making upgrade/migration plans a few months before your OS reaches EOL), anyway, but sometimes people cling to old distros like an old security blanket…so, I know there are still folks out there deploying new Debian 8 systems.
We’ll continue to maintain our Debian 8 repo and updates therein until June 2020 (when all updates stop upstream), but no new installations on Debian 8 will be supported.
Also be aware that CentOS/RHEL 6 also reaches end of life later this year. So, you shouldn’t be deploying new servers with that version of the OS, and should begin making migration plans over the coming months in order to move to CentOS 7 or CentOS 8 (support coming in a day or two).