- When registering with a 1.17+ API server, a CustomResourceDefinition conversion webhook can now request that only `v1` ConversionReview requests be sent to them. Previously, conversion webhooks were required to support receiving `v1beta1` ConversionReview...

begins. Communication blocks until the send can proceed.
A send on an unbuffered channel can proceed if a receiver is ready.
A send on a buffered channel can proceed if there is room in the buffer.
A send on a closed channel proceeds by causing a <a href="#Run_time_panics">run-time panic</a>.
A send on a <code>nil</code> channel blocks forever.
</p>

<pre>
ch &lt;- 3  // send value 3 to channel ch
</pre>

<p>

- The `AdmissionReview` API sent to and received from admission webhooks has been promoted to `admission.k8s.io/v1`. Webhooks can specify a preference for receiving `v1` AdmissionReview objects with `admissionReviewVersions: ["v1","v1beta1"]`, and must respond with an API object in the same `apiVersion` they are sent. When webhooks use `admission.k8s.io/v1`, the following additional validation is performed on their responses:...

- Fix: set nil cache entry based on old cache ([#87593](https://github.com/kubernetes/kubernetes/pull/87593), [@aramase](https://github.com/aramase)) [SIG Cloud Provider]

allow an optional `tokenAttribute` field to be configured. When it is set, the kubelet will provision a token with the given audience bound to the current pod and its service account. This KSA token along with required annotations on the KSA defined in configuration will be sent to the credential provider plugin via its standard input (along with the image information that is already sent today). The KSA annotations to be sent are configurable in the kubelet credential provider configuration. ([...

* ActiveDeadlineSeconds is validated in workload controllers now, make sure it's not set anywhere (it shouldn't be set by default and having it set means your controller will restart the Pods at some point) ([#38741](https://github.com/kubernetes/kubernetes/pull/38741), [@sandflee](https://github.com/sandflee))

- Kube-apiserver: ensures the namespace of objects sent to admission webhooks matches the request namespace. Previously, objects without a namespace set would have the request namespace populated after mutating admission, and objects with a namespace that did not match the request namespace would be rejected after admission. ([#94637](https://github....

* 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://gith...

* 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://gith...

- Spedup kubectl by >10 when calling out to kube-apiserver for discovery information. ([#73345](https://github.com/kubernetes/kubernetes/pull/73345), [@sttts](https://github.com/sttts))
- Fixed watch to not send the same set of events multiple times causing watcher to go back in time ([#73845](https://github.com/kubernetes/kubernetes/pull/73845), [@wojtek-t](https://github.com/wojtek-t))