- Kubeadm: fix panic in the command "kubeadm certs check-expiration" when "/etc/kubernetes/pki" exists but cannot be read. ([#124124](https://github.com/kubernetes/kubernetes/pull/124124), [@carlory](https://github.com/carlory)) [SIG Cluster Lifecycle]

  - A namespaced object with an ownerReference referencing a uid of a namespaced kind which does not exist in the same namespace is now consistently treated as though that owner does not exist, and the child object is deleted.

* Add CSI Migration Shim for VerifyVolumesAreAttached and BulkVolumeVerify ([#80443](https://github.com/kubernetes/kubernetes/pull/80443), [@davidz627](https://github.com/davidz627))

- Fixed a bug that prevents a PersistentVolume that has a PersistentVolumeClaim UID which doesn't exist in local cache but exists in etcd from being updated to the Released phase. ([#105211](https://github.com/kubernetes/kubernetes/pull/105211), [@xiaopingrubyist](https://github.com/xiaopingrubyist))

- Azure: avoid setting cached Sku when updating VMSS and VMSS instances ([#102005](https://github.com/kubernetes/kubernetes/pull/102005), [@feiskyer](https://github.com/feiskyer)) [SIG Cloud Provider]
- Fix a bug that a preemptor pod may exist as a phantom in the scheduler. ([#102498](https://github.com/kubernetes/kubernetes/pull/102498), [@Huang-Wei](https://github.com/Huang-Wei)) [SIG Scheduling]

## Changelog since v1.5.5

### Other notable changes

* kube-up (with gce/gci and gce/coreos providers) now ensures the authentication token file contains correct tokens for the control plane components, even if the file already exists (ensures upgrades and downgrades work successfully) ([#43676](https://github.com/kubernetes/kubernetes/pull/43676), [@liggitt](https://github.com/liggitt))

### Ephemeral Containers Graduate to Stable

- If the parent directory of the file specified in the `--audit-log-path` argument does not exist, Kubernetes now creates it. ([#111227](https://github.com/kubernetes/kubernetes/pull/111227), [@vpnachev](https://github.com/vpnachev)) [SIG Auth]

- If the parent directory of the file specified in the `--audit-log-path` argument does not exist, Kubernetes now creates it. ([#111225](https://github.com/kubernetes/kubernetes/pull/111225), [@vpnachev](https://github.com/vpnachev)) [SIG Auth]

* API Registration is now in beta. ([#45247](https://github.com/kubernetes/kubernetes/pull/45247), [@mbohlool](https://github.com/mbohlool))