- kubeadm: removed the deprecated flag `--experimental-output`, please use the flag `--output` instead that serves the same purpose. Affected commands are: `kubeadm config images list`, `kubeadm token list`, `kubeadm upgrade plan`, `kubeadm certs check-expiration`. ([#126914](https://github.com/kubernetes/kubernetes/pull/126914),...

Executing `kubeadm init phase kubeconfig all` or just `kubeadm init` will now generate the new `super-admin.conf` file. The cluster admin can then decide to keep the file present on a node host or move it to a safe location. `kubadm certs renew` will renew the certificate in `super-admin.conf` to one year if the file exists; if it does not exist a "MISSING" note will be printed. `kubeadm upgrade apply` for this release will migrate this particular node to the two file setup. Subsequent kubeadm releases...

- 'kubeadm: marked the flag "--experimental-output'' as deprecated (it will
  be removed in a future release) and added a new flag ''--output" that serves the
  same purpose. Affected commands are - "kubeadm config images list", "kubeadm token

- kubeadm: if the `NodeLocalCRISocket` feature gate is enabled, remove the `kubeadm.alpha.kubernetes.io/cri-socket` annotation from a given node on `kubeadm upgrade`. ([#129279](https://github.com/kubernetes/kubernetes/pull/129279), [@HirazawaUi](https://github.com/HirazawaUi)) [SIG Cluster Lifecycle and Testing]

- kubeadm: added the `WaitForAllControlPlaneComponents` feature gate. It could be used to tell kubeadm to wait for all control plane components to be ready when running "kubeadm init" or "kubeadm join --control-plane". Previously, kubeadm only waited for the kube-apiserver. The "kubeadm join" workflow now includes a new experimental phase called "wait-control-plane". This phase was marked as non-experimental...

- Fix error handling and potential go null pointer exception in kubeadm upgrade diff ([#80648](https://github.com/kubernetes/kubernetes/pull/80648), [@odinuge](https://github.com/odinuge))
- kubeadm: fall back to client version in case of certain HTTP errors ([#80024](https://github.com/kubernetes/kubernetes/pull/80024), [@RainbowMango](https://github.com/RainbowMango))

 - The default Bootstrap Token created with `kubeadm init` v1.8 expires
 and is deleted after 24 hours by default to limit the exposure of the
 valuable credential. You can create a new Bootstrap Token with
 `kubeadm token create` or make the default token permanently valid by specifying
 `--token-ttl 0` to `kubeadm init`. The default token can later be deleted with
 `kubeadm token delete`.

- Kubeadm: fixed an etcd learner-mode bug by preparing an etcd static pod manifest before promoting ([#115038](https://github.com/kubernetes/kubernetes/pull/115038), [@tobiasgiese](https://github.com/tobiasgiese))

- Kubeadm: Added support for additional authentication strategies in `kubeadm join` with discovery/kubeconfig file: client-go authentication plugins (`exec`), `tokenFile`, and `authProvider.` ([#110553](https://github.com/kubernetes/kubernetes/pull/110553), [@tallaxes](https://github.com/tallaxes))

- Kubeadm: graduated the kubeadm specific feature gate `WaitForAllControlPlaneComponents` to GA. The feature gate is was locked to always be enabled and on node initialization kubeadm performed a health check for all control plane components and not only the `kube-apiserver`....