ReplicationController, but its [selector](http://kubernetes.io/docs/user-guide/labels/#label-selectors) is more general (supports set-based selector; whereas ReplicationController
only supports equality-based selector).
  * Scale subresource support is now expanded to ReplicaSets along with
ReplicationControllers and Deployments. Scale now supports two different types

    This particularly-subtle bug was caused by us assigning each `OkHttpClient` instance its own
    `NullProxySelector` when an explicit proxy is configured. But we don't share connections when
    the proxy selectors are different. Ugh!


## Version 4.2.0

_2019-09-10_

 *  New: API to decode a certificate and private key to create a `HeldCertificate`. This accepts a

 *  Fix: Don't retry requests that failed due to timeouts.
 *  Fix: Cache 302s and 308s that include appropriate response headers.
 *  Fix: Improve pooling of connections that use proxy selectors.
 *  Fix: Don't leak connections when using ALPN on the desktop.
 *  Fix: Update Jetty ALPN to `7.1.2.v20141202` (Java 7) and `8.1.2.v20141202` (Java 8).

(document.getElementById(prefix))\n\n    return prefix\n  },\n\n  getSelectorFromElement(element) {\n    let selector = element.getAttribute('data-target')\n\n    if (!selector || selector === '#') {\n      const hrefAttr = element.getAttribute('href')\n      selector = hrefAttr && hrefAttr !== '#' ? hrefAttr.trim() : ''\n    }\n\n    try {\n      return document.querySelector(selector) ? selector : null\n    } catch (_) {\n      return null\n    }\n  },\n\n  getTransitionDurationFromElement(element)...

  - `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.

* restore ability to run against secured etcd ([#21535](https://github.com/kubernetes/kubernetes/pull/21535), [@AdoHe](https://github.com/AdoHe))

### Other notable changes

* validate that daemonsets don't have empty selectors on creation ([#23530](https://github.com/kubernetes/kubernetes/pull/23530), [@mikedanese](https://github.com/mikedanese))

* 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))