- The feature gate was mentioned as `csiMigrationRBD` where it should have been `CSIMigrationRBD` to be in parity with other migration plugins. This release correct the same and keep it as `CSIMigrationRBD`.
  
  users who have configured this feature gate as `csiMigrationRBD` has to reconfigure the same to `CSIMigrationRBD` from this release. ([#107554](https://github.com/kubernetes/kubernetes/pull/107554), [@humblec](https://github.com/humblec)) [SIG Storage]

- The feature gate was mentioned as `csiMigrationRBD` where it should have been `CSIMigrationRBD` to be in parity with other migration plugins. This release correct the same and keep it as `CSIMigrationRBD`.
    users who have configured this feature gate as `csiMigrationRBD` has to reconfigure the same to `CSIMigrationRBD` from this release. ([#107554](https://github.com/kubernetes/kubernetes/pull/107554), [@humblec](https://github.com/humblec))

For stable features, the `kubectl` tool follows the Kubernetes [version skew policy](https://kubernetes.io/releases/version-skew-policy/);
however, kubectl v1.21 and older do not support the new API for ephemeral containers.

- [`KT-56197`](https://youtrack.jetbrains.com/issue/KT-56197) If use classpathSnapshot, the invoke place of subclass's super function who has default parameters will not recompiled if it is incremental build

  // to see the host machine. Most containers will NOT need this.
  // More info: https://kubernetes.io/docs/concepts/storage/volumes#hostpath
  // ---
  // TODO(jonesdl) We need to restrict who can use host directory mounts and who can/can not
  // mount host directories as read/write.
  // +optional
  optional HostPathVolumeSource hostPath = 1;

  // emptyDir represents a temporary directory that shares a pod's lifetime.

* The shortcuts that were moved server-side in at least 1.9 have been removed from being hardcoded in kubectl. This means that the client-based restmappers have been moved to client-go, where everyone who needs them can have access. ([#63507](https://github.com/kubernetes/kubernetes/pull/63507), [@deads2k](https://github.com/deads2k))

* Alpha Initializers have been removed from kubeadm admission control.  Kubeadm users who still want to use Initializers can use apiServerExtraArgs through the kubeadm config file to enable it when booting up the cluster. ([#58428](https://github.com/kubernetes/kubernetes/pull/58428), [@dixudx](https://github.com/dixudx))

* Add masquerading rules by default to GCE/GKE ([#55178](https://github.com/kubernetes/kubernetes/pull/55178), [@dnardo](https://github.com/dnardo))
* kubeadm now produces error during preflight checks if swap is enabled. Users, who can setup kubelet to run in unsupported environment with enabled swap, will be able to skip that preflight check. ([#55399](https://github.com/kubernetes/kubernetes/pull/55399), [@kad](https://github.com/kad))

* kubeadm: use the CRI for preflights checks ([#55055](https://github.com/kubernetes/kubernetes/pull/55055), [@runcom](https://github.com/runcom))
* kubeadm now produces error during preflight checks if swap is enabled. Users, who can setup kubelet to run in unsupported environment with enabled swap, will be able to skip that preflight check. ([#55399](https://github.com/kubernetes/kubernetes/pull/55399), [@kad](https://github.com/kad))

- Kubeadm: when using a custom image repository for CoreDNS kubeadm now will append the "coredns"  image name instead of  "coredns/coredns", thus restoring the behaviour existing before the v1.21 release. Users who rely on nested folder for the coredns image should set the "clusterConfiguration.dns.imageRepository" value including the nested path name (e.g using "registry.company.xyz/coredns" will force kubeadm to use "registry.company.xyz/coredns/coredns" image)....