* The `name` field for specified webhooks must be unique for `MutatingWebhookConfiguration` and `ValidatingWebhookConfiguration` objects created via `admissionregistration.k8s.io/v1`
    * The `admissionregistration.k8s.io/v1beta1` versions of `MutatingWebhookConfiguration` and `ValidatingWebhookConfiguration` are deprecated and will no longer be served in v1.19.

- When registering with a 1.17+ API server, MutatingWebhookConfiguration and ValidatingWebhookConfiguration objects can now request that only `v1` AdmissionReview requests be sent to them. Previously, webhooks were required to support receiving `v1beta1` AdmissionReview requests as well for compatibility with API servers <= 1.15.

- To address the possibility of dry-run requests overwhelming admission webhooks that rely on side effects and a reconciliation mechanism, a new field is being added to `admissionregistration.k8s.io/v1beta1.ValidatingWebhookConfiguration` and `admissionregistration.k8s.io/v1beta1.MutatingWebhookConfiguration` so that webhooks can explicitly register as having dry-run support. If a dry-run request is made on a resource that triggers a non dry-run supporting webhook, the...

* Fixed an issue making it possible to create a situation in which two webhooks make it impossible to delete each other. ValidatingWebhooks and MutatingWebhooks will not be called on admission requests for ValidatingWebhookConfiguration and MutatingWebhookConfiguration objects in the admissionregistration.k8s.io group ([#59840](https://github.com/kubernetes/kubernetes/pull/59840), [@jennybuckley](https://github.com/jennybuckley))

- Third party device monitoring is now beta, and enabled by default (KubeletPodResources). ([#77274](https://github.c...

- Added the `MatchConditions` field to `ValidatingWebhookConfiguration` and `MutatingWebhookConfiguration` for the v1beta and v1 apis. 
  

APIs

A number of APIs are no longer serving specific Beta versions in favour of the GA version of those APIs. All existing objects can be interacted with via general availability APIs. This removal includes beta versions of `ValidatingWebhookConfiguration`, `MutatingWebhookConfiguration`, `CustomResourceDefinition`, `APIService`, `TokenReview`, `SubjectAccessReview`, `CertificateSigningRequest`, `Lease`, `Ingress`, and `IngressClass` APIs. For the full list check out [Deprecated API Migration...