- Clients should reload the token from disk periodically (once per minute is recommended) to ensure they continue to use a valid token. `k8s.io/client-go` version v11.0.0+ and v0.15.0+ reload tokens automatically.

* kubeadm: fix wrong default value for the "upgrade node --certificate-renewal" flag. ([#83528](https://github.com/kubernetes/kubernetes/pull/83528), [@neolit123](https://github.com/neolit123))
* IP validates if a string is a valid IP address ([#83104](https://github.com/kubernetes/kubernetes/pull/83104), [@zouyee](https://github.com/zouyee))

- The kubectl --dry-run flag now accepts the values 'client', 'server', and 'none', to support client-side and server-side dry-run strategies. The boolean and unset values for the --dry-run flag are deprecated and a value will be required in a future version. ([#87580](https://github.com/kubernetes/kubernetes/pull/87580), [@julianvmodesto](https://github.com/julianvmodesto))...

- The Conformance test "validates that there is no conflict between pods with same hostPort but different hostIP and protocol" now validates the connectivity to each hostPort, in addition to the functionality. ([#96627](https://github.com/kubernetes/kubernetes/pull/96627), [@aojea](https://github.com/aojea)) [SIG Scheduling and Testing]...

  - `servicePort` -> `service.port.name` (for string values)
  - `servicePort` -> `service.port.number` (for numeric values)
  - `pathType` no longer has a default value in v1; "Exact", "Prefix", or "ImplementationSpecific" must be specified

  Other Ingress API updates:
  - backends can now be resource or service backends

- Changes behaviour of kube-proxy start; does not attempt to set specific `sysctl` values (which does not work in recent Kernel versions anymore in non-init namespaces), when the current sysctl values are already set higher. ([#103174](https://github.com/kubernetes/kubernetes/pull/103174), [@Napsty](https://github.com/Napsty))

Kubernetes supports node proxying, which allows clients of kube-apiserver to access endpoints of a Kubelet to establish connections to Pods, retrieve container logs, and more. While Kubernetes already validates the proxying address for Nodes, a bug in kube-apiserver made it possible to bypass this validation. Bypassing this validation could allow authenticated requests destined for Nodes to be redirected to the API Server through its private network.

- The `TerminationGracePeriodSeconds` on pod specs and container probes should not be negative. Negative values of `TerminationGracePeriodSeconds` will be treated as the value `1s` on the delete path. Immutable field validation will be relaxed in order to update negative values. In a future release, negative values will not be permitted. ([#98866](https://github.com/kubernetes/kubernetes/pull/98866), [@wzshiming](https://github.com/wzshiming))

Kubernetes supports node proxying, which allows clients of kube-apiserver to access endpoints of a Kubelet to establish connections to Pods, retrieve container logs, and more. While Kubernetes already validates the proxying address for Nodes, a bug in kube-apiserver made it possible to bypass this validation. Bypassing this validation could allow authenticated requests destined for Nodes to be redirected to the API Server through its private network.

  * Passing multiple values separated by a comma in a single --from-literal flag is no longer supported. Please use multiple --from-literal flags to provide multiple values.