- The "JoinConfiguration.discovery.timeout" field has been replaced by "JoinConfiguration.timeouts.discovery".
  - The "ClusterConfiguration.timeoutForControlPlane" field has been replaced by "{Init|Join}Configuration.timeouts.controlPlaneComponentHealthCheck".
  Please use the command "kubeadm config migrate" to migrate your existing v1beta3 configuration to v1beta4.

- Kubeadm: Remove the deprecated hyperkube image support in `v1beta3`. This implies removal of `ClusterConfiguration.UseHyperKubeImage.` ([#101537](https://github.com/kubernetes/kubernetes/pull/101537), [@neolit123](https://github.com/neolit123))

  - apiserver-advertise-address / apiserver-bind-port: use either localAPIEndpoint from InitConfiguration or controlPlaneEndpoint from ClusterConfiguration.
  - cluster-name: use clusterName from ClusterConfiguration
  - cert-dir: use certificatesDir from ClusterConfiguration ([#94879](https://github.com/kubernetes/kubernetes/pull/94879), [@knight42](https://github.com/knight42)) [SIG Cluster Lifecycle]

- kubeadm: The ControlPlaneEndpoint was moved from the API config struct to ClusterConfiguration ([#67830](https://github.com/kubernetes/kubernetes/pull/67830), [@fabriziopandini](https://github.com/fabriziopandini))
- kubeadm: InitConfiguration now consists of two structs: InitConfiguration and ClusterConfiguration ([#67441](https://github.com/kubernetes/kubernetes/pull/67441), [@rosti](https://github.com/rosti))

- kubeadm ClusterConfiguration now supports featureGates: IPv6DualStack: true ([#80145](https://github.com/kubernetes/kubernetes/pull/80145), [@Arvinderpal](https://github.com/Arvinderpal))

image repository for CoreDNS kubeadm now will append the "coredns"  image name instead of  "coredns/coredns", thus restoring the behaviour existing before the v1.21 release. Users who rely on nested folder for the coredns image should set the "clusterConfiguration.dns.imageRepository" value including the nested path name (e.g using "registry.company.xyz/coredns" will force kubeadm to use "registry.company.xyz/coredns/coredns" image). No action is needed if using the default registry (k8s.gcr.io). ([...

- Kubeadm: avoided uploading a defaulted flag value "--authorization-mode=Node,RBAC" for the kube-apiserver in the ClusterConfiguration stored in the "kube-system/kubeadm-config" ConfigMap. "Node,RBAC" are already the kubeadm defaults for this flag, so this action is redundant. ([#123555](https://github.com/kubernetes/kubernetes/pull/123555), [@neolit123](https://github.com/neolit123))...

- Remove `tolerate-unready-endpoints` annotation...

 - Kubeadm now respects user specified etcd versions in the ClusterConfiguration and properly uses them. If users do not want to stick to the version specified in the ClusterConfiguration, they should edit the kubeadm-config config map and delete it. ([#89588](https://github.com/kubernetes/kubernetes/pull/89588), [@rosti](https://github.com/rosti)) [SIG Cluster Lifecycle]...

- Kubeadm: external etcd endpoints passed in the `ClusterConfiguration` that have Unicode characters are no longer IDNA encoded (converted to Punycode). They are now just URL encoded as per Go's implementation of RFC-3986, have duplicate "/" removed from the URL paths, and passed like that directly to the `kube-apiserver`...