`autoscaling/v2alpha1`. The Horizontal Pod Autoscaler changes include support for status conditions, and autoscaling on memory and custom metrics.

* The metrics APIs, `custom-metrics.metrics.k8s.io` and `metrics`, were moved from `v1alpha1` to `v1beta1`, and renamed to `custom.metrics.k8s.io` and `metrics.k8s.io`, respectively. If you have deployed a custom metrics adapter, ensure that it supports the new API version. If you have deployed Heapster in aggregated API server mode, upgrade...

- Fixes an issue that can result in namespaced custom resources being orphaned when their namespace is deleted, if the CRD defining the custom resource is removed concurrently with namespaces being deleted, then recreated. ([#93790](https://github.com/kubernetes/kubernetes/pull/93790), [@liggitt](https://github.com/liggitt)) [SIG API Machinery...

- API paging is now enabled for custom resource definitions, custom resources and APIService objects. ([#67861](https://github.com/kubernetes/kubernetes/pull/67861), [@liggitt](https://github.com/liggitt))

- Fixes an issue that can result in namespaced custom resources being orphaned when their namespace is deleted, if the CRD defining the custom resource is removed concurrently with namespaces being deleted, then recreated. ([#93790](https://github.com/kubernetes/kubernetes/pull/93790), [@liggitt](https://github.com/liggitt)) [SIG API Machinery...

- Fixed a bug at `kube-apiserver` start where `APIService` objects for custom resources could be deleted and recreated. ([#118104](https://github.com/kubernetes/kubernetes/pull/118104), [@liggitt](https://github.com/liggitt))

    - [**API Machinery**](#api-machinery-3)
      - [**Admission Control**](#admission-control)
      - [**API & API server**](#api-&-api-server)
      - [**Audit**](#audit)
      - [**Custom Resources**](#custom-resources)
      - [**Other**](#other)
    - [**Apps**](#apps-1)
    - [**Auth**](#auth-3)
      - [**Audit**](#audit-1)
      - [**RBAC**](#rbac)
      - [**Other**](#other-1)
      - [**GCE**](#gce)

- Fixes a bug at kube-apiserver start where APIService objects for custom resources could be deleted and recreated. ([#118104](https://github.com/kubernetes/kubernetes/pull/118104), [@liggitt](https://github.com/liggitt)) [SIG API Machinery and Testing]

os.Hostname() will be used, in that order. ([#56812](https://github.com/kubernetes/kubernetes/pull/56812), [@dims](https://github.com/dims))

* Custom resources can be listed with a set of grouped resources (category) by specifying the categories in the [CustomResourceDefinition spec](https://kubernetes.io/docs/tasks/access-kubernetes-api/extend-api-custom-resource-definitions/#categories). Example: They can be used with `kubectl get important`, where `important` is a category. ([#59561](https://...

- The rules for incrementing `metadata.generation` of custom resources changed: ([#69059](https://github.com/kubernetes/kubernetes/pull/69059), [@caesarxuchao](https://github.com/caesarxuchao))
  - If the custom resource participates the spec/status convention, the metadata.generation of the CR increments when there is any change, except for the changes to the metadata or the changes to the status.

    * Custom apiservers built with the latest apiserver library will have the 100MB limit on the body of resource requests as well. The limit can be altered via ServerRunOptions.MaxRequestBodyBytes.