</p>
<ul>
	<li>Every element must have a key.
	</li>
	<li>Each key must be a valid field <a href="#Selectors">selector</a>
	    [<a href="#Go_1.27">Go 1.27</a>] for a (possibly promoted) field
	    of the struct; the key selects that field.
	</li>
	<li>The types of the embedded fields (if any) <a href="#Selectors">traversed</a>
	    to reach a selected field must not be pointer types.
	</li>

  - `create service externalname` ([#34789](https://github.com/kubernetes/kubernetes/pull/34789), [@adohe](https://github.com/adohe))
- `set selector` - update selector labels ([#38966](https://github.com/kubernetes/kubernetes/pull/38966), [@kargakis](https://github.com/kargakis))

 selector mutation in
 a consistent way. This restriction may be lifted in the future, but
 it is likely that that selectors will remain immutable after the move to v1.
 You can continue to use code that depends on mutable selectors by calling
 the apps/v1beta1 API in this release, but you should start planning for code
 that does not depend on mutable selectors.

* Quota admission configuration api graduated to v1beta1 ([#66156](https://github.com/kubernetes/kubernetes/pull/66156), [@vikaschoudhary16](https://github.com/vikaschoudhary16))

### **Security**
#### Admission Control
* [alpha] Add [extensible external admission control](https://kubernetes.io/docs/admin/extensible-admission-controllers/).

#### TLS Bootstrapping

- Added ListMeta.RemainingItemCount. When responding to a LIST request, if the server has more data available, and if the request does not contain label selectors or field selectors, the server sets the ListOptions.RemainingItemCount to the number of remaining objects. ([#75993](https://github.com/kubernetes/kubernetes/pull/75993), [@caesarxuchao](https://github.com/caesarxuchao))

* For Deployment, ReplicaSet, and DaemonSet, selectors are now immutable when updating via the new `apps/v1beta2` API. For backward compatibility, selectors can still be changed when updating via `apps/v1beta1` or `extensions/v1beta1`. ([#50719](https://github.com/kubernetes/kubernetes/pull/50719), [@crimsonfaith91](https://github.com/crimsonfaith91))...

    * setting `KUBE_PROXY_DAEMONSET=true` in kube-up will now set a `node.kubernetes.io/kube-proxy-ds-ready=true` label on new nodes. In v1.16, the kube-proxy daemonset add-on will switch to using that label as a node selector.
    * In 1.16, the masq-agent daemonset add-on will switch to using `node.kubernetes.io/masq-agent-ds-ready` as a node selector.

- Aggregated discovery supports both `v2beta1` and v2 types and feature is promoted to GA. ([#122882](https://github.com/kubernetes/kubernetes/pull/122882), [@Jefftree](https://github.com/Jefftree))

- Added support for specifying `controlplane` or `cluster` egress selectors in JWT authenticators via the `issuer.egressSelectorType` field in the `AuthenticationConfiguration.jwt` array. If unset, the previous behavior of using no egress selector is preserved. This functionality requires the `StructuredAuthenticationConfigurationEgressSelector` beta feature gate (enabled by default). ([#132768](https://...