- When `SchedulerQueueingHint` is enabled,
  the scheduler's in-tree plugins now subscribe to specific node events to decide whether to requeue Pods.
  This allows the scheduler to handle cluster events faster with less memory.

  Specific node events include updates to taints, tolerations or allocatable.

- Updated the HPA controller so that it no longer emitted a `FailedRescale` event if a scale operation initially failed due to a conflict but succeeded after a retry; it now emitted a `SuccessfulRescale` event in this case. A `FailedRescale` event was still emitted if all retries were exhausted. ([#132007](https://github.com/kubernetes/kubernetes/pull/132007), [@AumPatel1](https://github.com/AumPatel1)) [SIG Apps...

- `client-go` event library allows customizing spam filtering function. 
  It is now possible to override `SpamKeyFunc`, which is used by event filtering to detect spam in the events. ([#103918](https://github.com/kubernetes/kubernetes/pull/103918), [@olagacek](https://github.com/olagacek))
- `client-go`, using log level 9, traces the following events of a HTTP request:
      - DNS lookup
      - TCP dialing

- Kube-scheduler now falls back to emitting events using core/v1 Events when events.k8s.io/v1beta1 is disabled. ([#83692](https://github.com/kubernetes/kubernetes/pull/83692), [@yastij](https://github.com/yastij))

- Fix a bug where events/v1 Events with similar event type and reporting instance were not aggregated by client-go. ([#112365](https://github.com/kubernetes/kubernetes/pull/112365), [@dgrisonnet](https://github.com/dgrisonnet)) [SIG API Machinery and Instrumentation]

- Fix kubectl printer to correctly handle timestamps of events emitted using events.k8s.io API ([#94226](https://github.com/kubernetes/kubernetes/pull/94226), [@ingvagabund](https://github.com/ingvagabund)) [SIG CLI]
  ```sh
  $ kubectl get event
  LAST SEEN   TYPE     REASON              OBJECT                        MESSAGE

- `kubectl` will not print events if `--show-events=false` argument is passed to
  describe PVC subcommand. ([#120380](https://github.com/kubernetes/kubernetes/pull/120380), [@MaGaroo](https://github.com/MaGaroo))
- `scheduler`: Fixed missing field `apiVersion` from events reported by the taint

    * fixed bugs and improved performance in Stackdriver Sink
* fluentd-gcp addon: Fix a bug in the event-exporter, when repeated events were not sent to Stackdriver. ([#50511](https://github.com/kubernetes/kubernetes/pull/50511), [@crassirostris](https://github.com/crassirostris))

* add support for client-side spam filtering of events ([#47367](https://github.com/kubernetes/kubernetes/pull/47367), [@derekwaynecarr](https://github.com/derekwaynecarr))
* Provide a way to omit Event stages in audit policy ([#49280](https://github.com/kubernetes/kubernetes/pull/49280), [@CaoShuFeng](https://github.com/CaoShuFeng))

  - The `export` query parameter for list API calls, deprecated since v1.14, will be removed in v1.18.
  - The `series.state` field in the events.k8s.io/v1beta1 Event API is deprecated and will be removed in v1.18 ([#75987](https://github.com/kubernetes/kubernetes/pull/75987), [@yastij](https://github.com/yastij))

- kubeadm