### API Machinery

#### kube-apiserver
* Fixed an issue with `APIService` auto-registration. This issue affected rolling restarts of HA API servers that added or removed API groups being served.([#51921](https://github.com/kubernetes/kubernetes/pull/51921))

*   Custom resources served by CustomResourceDefinition objects now support field selectors for `metadata.name` and `metadata.namespace`. Also fixed an issue with watching a single object; earlier versions could watch only a collection, and so a watch on an instance would fail....

b???hwsohw?i!.&0pci,1pci,8302,a&minifed,tad-b,?b&altig,uhtig,?czh,d&etpyrcs.tneilc,raobelgaeb,uolcropav,?e&civedniser,don&ppad.sndnyd,repyh,?egipa,l&bbub.ndc,ej,?nilnigol,sufxob,t&i&beulb,snoehtnap,?newtu,ybeeb.saap,?varb,?g&n&alkrad,i&gatsniser.secived,tsoh&-br.etis,ytsoh,???ro??k&coregrof.di,o&obtig,rgn:.&as,ni,p&a,j,?su,u&a,e,??,?ramytefasresworb,?lim?mo&c?n??n&aicisum,mtsp:.kcom,,yded,?o&c?idutsxiw,toq,?p&opilol,pa&-arusah,etybeeb.1dkes,??r&ddaym,e&tsneum-hf,vres&cisab,lautriv,??ial.sppa,?s&...

    assertThat(server.takeRequest().exchangeIndex).isEqualTo(1)
  }

  @Test
  fun streamDiscardingIsTimely() {
    // This response takes at least a full second to serve: 10,000 bytes served 100 bytes at a time.
    server.enqueue(
      MockResponse
        .Builder()
        .body(Buffer().write(ByteArray(10000)))
        .throttleBody(100, 10, TimeUnit.MILLISECONDS)
        .build(),

- All resources within the `rbac.authorization.k8s.io/v1alpha1` and `rbac.authorization.k8s.io/v1beta1` API groups are deprecated in favor of `rbac.authorization.k8s.io/v1`, and will no longer be served in v1.20. ([#84758](https://github.com/kubernetes/kubernetes/pull/84758), [@liggitt](https://github.com/liggitt))

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

* Alpha support for OpenAPI (aka. Swagger 2.0) specification served on /swagger.json (enabled by default)  ([#30233](https://github.com/kubernetes/kubernetes/pull/30233), [@mbohlool](https://github.com/mbohlool))

- The `node.k8s.io/v1alpha1` RuntimeClass API is no longer served. Use the `node.k8s.io/v1` API version, available since v1.20 ([#103061](https://github.com/kubernetes/kubernetes/pull/103061), [@SergeyKanzhelev](https://github.com/SergeyKanzhelev))

* Added Establishing Controller on CRDs to avoid race between Established condition and CRs actually served. In HA setups, the Established condition is delayed by 5 seconds. ([#63068](https://github.com/kubernetes/kubernetes/pull/63068), [@xmudrii](https://github.com/xmudrii))

- Kube-apiserver: Fixes a possible 1.34 performance regression calculating object size statistics for resources not served from the watch cache, typically only Events ([#133879](https://github.com/kubernetes/kubernetes/pull/133879), [@serathius](https://github.com/serathius)) [SIG API Machinery and Etcd]