- 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),...

- Kubeadm: remove the deprecated command "kubeadm alpha kubeconfig". Please use "kubeadm kubeconfig" instead. ([#101938](https://github.com/kubernetes/kubernetes/pull/101938), [@knight42](https://github.com/knight42)) [SIG Cluster Lifecycle]

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...

- Kubeadm: deprecated command "alpha selfhosting pivot" is now removed. ([#97627](https://github.com/kubernetes/kubernetes/pull/97627), [@knight42](https://github.com/knight42))

- 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: add support for dry running `kubeadm join`. The new flag `kubeadm join --dry-run` is similar to the existing flag for `kubeadm init/upgrade` and allows you to see what changes would be applied. ([#103027](https://github.com/kubernetes/kubernetes/pull/103027), [@Haleygo](https://github.com/Haleygo))