See the constant defined below which correlates kubernetes and etcd versions:
Is the etcd version provided the minimum supported, maximum supported, or only supported version of etcd to use with the corresponding k8s version?
For example, does k8s v1.22 support etcd 3.4? Does k8s v1.21 support etcd 3.5? It is not immediately clear to me from the documentation and usage of this constant.