- kube-scheduler

  - Migrate scheduler to use v1beta1 Event API. any tool targeting scheduler events needs to use v1beta1 Event API ([#78447](https://github.com/kubernetes/kubernetes/pull/78447), [@yastij](https://github.com/yastij))

- kubeadm

  - 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

- 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]

- 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.

    * [prometheus-to-sd addon] Bump prometheus-to-sd to 0.3.1 to pick up security fixes, bug fixes and new features.
    * [event-exporter addon] Bump event-exporter to 0.2.3 to pick up security fixes.

- `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

- Disable watchcache for events.k8.io/Event resource for compatibility with core/Event. ([#96117](https://github.com/kubernetes/kubernetes/pull/96117), [@wojtek-t](https://github.com/wojtek-t)) [SIG Scalability]

- Disable watchcache for events.k8.io/Event resource for compatibility with core/Event. ([#96117](https://github.com/kubernetes/kubernetes/pull/96117), [@wojtek-t](https://github.com/wojtek-t)) [SIG Scalability]

- `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

    * 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))