- When registering with a 1.17+ API server, a CustomResourceDefinition conversion webhook can now request that only `v1` ConversionReview requests be sent to them. Previously, conversion webhooks were required to support receiving `v1beta1` ConversionReview requests as well for compatibility...

- Static pods were taking extra time to be restarted after being updated.  Static pods that are waiting to restart were not correctly counted in `kubelet_working_pods`. ([#116995](https://github.com/kubernetes/kubernetes/pull/116995), [@smarterclayton](https://github.com/smarterclayton)) [SIG Node]

- The fallback behavior of the Downward API's `resourceFieldRef` field was updated to account for pod-level resources: if container-level limits were not set, pod-level limits were now used before falling back to node allocatable resources. ([#132605](https://github.com/kubernetes/kubernetes/pull/132605), [@toVersus](https://github.com/toVersus)) [SIG Node, Scheduling and Testing]

- Fixed a bug where aggregator_unavailable_apiservice metrics were reported for deleted apiservices. ([#96421](https://github.com/kubernetes/kubernetes/pull/96421), [@dgrisonnet](https://github.com/dgrisonnet)) [SIG API Machinery and Instrumentation]

  returns `nil`. (It now returns a pointer to a zero-valued object, like the real
  clients do.) This will break some downstream unit tests that were testing
  `result == nil` rather than `err != nil`, and in some cases may expose bugs

- Fixed a suboptimal scheduler preemption behavior where potential preemption victims were violating Pod Disruption Budgets. ([#128307](https://github.com/kubernetes/kubernetes/pull/128307), [@NoicFank](https://github.com/NoicFank)) [SIG Scheduling]
- Fixed an issue in the kubelet that showed when writeable layers and read-only layers were at different paths within the same mount.

* The following deprecated flags were removed from `kube-controller-manager`:

  * `replication-controller-lookup-cache-size`
  * `replicaset-lookup-cache-size`
  * `daemonset-lookup-cache-size`

  Don't use these flags. Using deprecated flags causes the server to print a warning. Using a removed flag causes the server to abort the startup.

* The following deprecated flags were removed from `kubelet`:

   ([#123273](https://github.com/kubernetes/kubernetes/pull/123273),...

- Fixed a bug where the device resources allocated to an init container, with `containerRestartPolicy` of `Always`, were erroneously reused by a regular container. ([#120461](https://github.com/kubernetes/kubernetes/pull/120461),...

  managed by the GLBC Ingress Controller. This can cause the health checks to start failing,
  requiring you to reapply the manual edits.
  * This issue does not affect clusters that were already running Kubernetes v1.6.4 or higher.
  * This issue does not affect Health Checks that were left in the configuration
    [originally set by the GLBC Ingress Controller](https://github.com/kubernetes/ingress-nginx/tree/0.9.0-beta.1/controllers/gce#health-checks).