The use of dual-stack networking is not mandatory.
Although clusters are enabled to support dual-stack networking, Pods and Services continue to default to single-stack.
To use dual-stack networking: Kubernetes nodes have routable IPv4/IPv6 network interfaces, a dual-stack capable CNI network plugin is used, Pods are configured to be dual-stack and Services have their `.spec.ipFamilyPolicy` field set to either `PreferDualStack` or `RequireDualStack`.