- 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.

- Added warnings about workload resources (Pods, ReplicaSets, Deployments, Jobs, CronJobs, or ReplicationControllers) whose names are not valid DNS labels. ([#114412](https://github.com/kubernetes/kubernetes/pull/114412),...

    * Reduce logging agent buffer chunk limit to 512k to optimize performance.

* Feature gates now check minimum versions ([#54539](https://github.com/kubernetes/kubernetes/pull/54539), [@jamiehannaford](https://github.com/jamiehannaford))

  kind.

#### Behavioral Changes

 - For all kinds in the API group version, a spec.selector default value is no longer
 available, because it's incompatible with `kubectl
 apply` and strategic merge patch. You must explicitly set the spec.selector value
 in your manifest. An object with a spec.selector value that does not match the labels in
 its spec.template is invalid.

- The "value" part in the `wait --for=jsonpath='{expression}'[=value]` is now
  optional. If the value is not provided i.e., the command looks like `wait --for=jsonpath='{expression}'`
  then the wait condition is interpreted as matched when the expression returns

* The new default value for the --allow-privileged parameter of the Kubernetes-worker charm has been set to true based on changes which went into the Kubernetes 1.10 release. Before this change the default value was set to false. If you're installing Canonical Kubernetes you should expect this value to now be true by default and you should now look to use PSP (pod security policies).  ([#64104](https://git...

* 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))

  - path definitions added a `pathType` field to allow indicating how the specified path should be matched against incoming requests. Valid values are `Exact`, `Prefix`, and `ImplementationSpecific` ([#88587](https://github.com/kubernetes/kubernetes/pull/88587), [@cmluciano](https://github.com/cmluciano)) [SIG Apps, Cluster Lifecycle and Network]

authentication now supports requiring specific claims with `--oidc-required-claim=<claim>=<value>` Previously, there was no mechanism for a user to specify claims in the OIDC authentication process that were requid to be present in the ID Token with an expected value. This version now makes it possible to require claims support for the OIDC authentication. It allows users to pass in a `--oidc-required-claims` flag, and `key=value` pairs in the API config, which will ensure that the specified required claims...