They are not using Docker for container runtime. It was deprecated in Kubernetes 1.20 and removed in 1.24 with almost everyone switching to containerd. Currently supported Kubernetes versions are 1.28/1.29/1.30. 1.27 is available as LTS from a few providers.
EDIT: Coworker mentioned there is a cri that lets you to continue to use Docker Engine in Kubernetes but I've never run across it.
EDIT: Coworker mentioned there is a cri that lets you to continue to use Docker Engine in Kubernetes but I've never run across it.