My dns server appears to be running debian 9. I'm upgrading it to Debian 10.8. Create a full backup before following these instructions. This consists of running apt update/upgrade on the existing system, changing the repositories from stretch to buster, running apt update/upgrade, and the running the apt full-upgrade.
After the upgrade, I verified that the bind dns server was running and resolving local and remote hosts. I also verified webmin was still accepting connections and able to view dns server settings.