### kubeadm
* A new label and taint is used for marking the master. The label is `node-role.kubernetes.io/master=""` and the taint has the effect `NoSchedule`. Tolerate the `node-role.kubernetes.io/master="":NoSchedule` taint to schedule a workload on the master (a networking DaemonSet for example).
* The kubelet API is now secured, only cluster admins are allowed to access it.

- Improved CRI handling
  - crictl is no longer required in docker-only setups.
  - Better detection of installed CRI.
  - Better output for image pull errors.
- Improved air-gapped and offline support
  - kubeadm now handles air-gapped environments by using the local client version as a fallback.
  - Some kubeadm commands are now allowed to work in a completely offline mode.
- Certificate handling improvements:

In hexadecimal literals, letters <code>a</code> through <code>f</code>
and <code>A</code> through <code>F</code> represent values 10 through 15.
</p>

<p>
For readability, an underscore character <code>_</code> may appear after
a base prefix or between successive digits; such underscores do not change
the literal's value.
</p>
<pre class="ebnf">
int_lit        = decimal_lit | binary_lit | octal_lit | hex_lit .

- Ensured that the `node-role.kubernetes.io/master` taint is applied to the master with NoSchedule on GCE. ([#78183](https://github.com/kubernetes/kubernetes/pull/78183), [@cheftako](https://github.com/cheftako))

  - Make "kubeadm upgrade apply" add the "node-role.kubernetes.io/control-plane" label on existing nodes that only have the "node-role.kubernetes.io/master" label during upgrade.
  - Please adapt your tooling built on top of kubeadm to use the "node-role.kubernetes.io/control-plane" label.

`second stage` of the plan to migrate kubeadm away from the usage of the word `master` in labels and taints. For new clusters, the label `node-role.kubernetes.io/master` will no longer be added to control plane nodes, only the label `node-role.kubernetes.io/control-plane` will be added. For clusters that are being upgraded to 1.24 with `kubeadm upgrade apply`, the command will remove the label `node-role.kubernetes.io/master` from existing control plane nodes. For new clusters, both the old taint `n...

  slightly stricter about what values will be accepted as IP addresses and network
  address ranges (“CIDR blocks”).
  
  In particular, octets within IPv4 addresses are not allowed to have any leading
  `0`s, and IPv4-mapped IPv6 values (e.g. `::ffff:192.168.0.1`) are forbidden.
  These sorts of values can potentially cause security problems when different
  components interpret the same string as referring to different IP addresses

- Kubeadm: removed the toleration for the `node-role.kubernetes.io/master` taint from the CoreDNS deployment of `kubeadm`. With the 1.25 release of kubeadm the taint `node-role.kubernetes.io/master` is no longer applied to control plane nodes and the toleration for it can be removed with the release of 1.26. You can also perform the same toleration removal from your own addon manifests....

- CustomResourceDefinition objects created with non-empty `caBundle` fields which are invalid or do not contain any certificates will not appear in discovery or serve endpoints until a valid `caBundle` is provided. Updates to CustomResourceDefinition are no longer allowed to transition a valid `caBundle` field to an invalid `caBundle` field, because this breaks serving of the existing Cus...

  <mime-type type="application/vnd.oasis.opendocument.text-master">
    <alias type="application/x-vnd.oasis.opendocument.text-master"/>
    <_comment>OpenDocument v1.0: Global Text document</_comment>
    <magic>
      <match type="string" offset="0" value="PK">
        <match type="string" offset="30"
               value="mimetypeapplication/vnd.oasis.opendocument.text-master"/>
      </match>
    </magic>