- The getters for the field name and typeDescription of the Reflector struct were renamed. ([#128035](https://github.com/kubernetes/kubernetes/pull/128035), [@alexanderstephan](https://github.com/alexanderstephan)) [SIG API Machinery]

- Changed how the API server handles updates to `.spec.defaultBackend` of Ingress objects.

- Fixed the API comments for the `FailIndex` Job pod failure policy action. ([#121764](https://github.com/kubernetes/kubernetes/pull/121764), [@mimowo](https://github.com/mimowo))
- Go API: the `ResourceRequirements` struct was replaced with `VolumeResourceRequirements` for use with volumes. ([#118653](https://github.com/kubernetes/kubernetes/pull/118653), [@pohly](https://github.com/pohly))

([#62695](https://github.com/kubernetes/kubernetes/pull/62695), [@CaoShuFeng](https://github.com/CaoShuFeng))
* HTTP transport now uses `context.Context` to cancel dial operations. k8s.io/client-go/transport/Config struct has been updated to accept a function with a `context.Context` parameter. This is a breaking change if you use this field in your code. ([#60012](https://github.com/kubernetes/kubernetes/pull/60012), [@ash2k](https://github.com/ash2k))

- kube-dns is deprecated and will not be supported in a future version ([#86574](https://github.com/kubernetes/kubernetes/pull/86574), [@SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle]

      * Open API now includes strategic merge patch tags (previously only in go struct tags) ([#44121](https://github.com/kubernetes/kubernetes/pull/44121), [@mbohlool](https://github.com/mbohlool))

  * Plugins

### API Change

- Added `omitempty` and `opt` tag to the API `v1beta2` AdminAccess type in the `DeviceRequestAllocationResult` struct. ([#132338](https://github.com/kubernetes/kubernetes/pull/132338), [@PatrickLaabs](https://github.com/PatrickLaabs))

- Introduced a breaking change to the `resource.k8s.io` API in its `AllocationResult` struct. This change allows a kubelet plugin for the `DynamicResourceAllocation` feature to service allocations from multiple resource driver controllers. ([#116332](https://github.com/kubernetes/kubernetes/pull/116332), [@klueska](https://github.com/klueska))...

- kubeadm: The ControlPlaneEndpoint was moved from the API config struct to ClusterConfiguration ([#67830](https://github.com/kubernetes/kubernetes/pull/67830), [@fabriziopandini](https://github.com/fabriziopandini))

* Mark image as deliberately optional in v1 Container struct.  Many objects in the Kubernetes API inherit the container struct and only Pods require the field to be set. ([#48406](https://github.com/kubernetes/kubernetes/pull/48406), [@gyliu513](https://github.com/gyliu513))