- Kubeadm: add the deprecated flag --port=0 to kube-controller-manager and kube-scheduler manifests to disable insecure serving. Without this flag the components by default serve (e.g. /metrics) insecurely on the default node interface (controlled by --address). Users that wish to override this behavior and enable insecure serving can pass...

  - The deprecated `--etcd-quorum-read` flag has been removed. Quorum reads are now always enabled when fetching data from etcd. Remove the `--etcd-quorum-read` flag from kube-apiserver invocations before upgrading.
- kube-controller-manager
  - The deprecated `--insecure-experimental-approve-all-kubelet-csrs-for-group` flag has been removed.
- kubelet

  - The deprecated --storage-versions flag has been removed. The storage versions will always be the default value built-in the kube-apiserver binary. ([#67678](https://github.com/kubernetes/kubernetes/pull/67678), [@caesarxuchao](https://github.com/caesarxuchao))

#### Network

- The deprecated flag `--conntrack-max` has been removed from kube-proxy. Users of this flag should switch to `--conntrack-min` and `--conntrack-max-per-core` instead. ([#78399](https://github.com/kubernetes/kubernetes/pull/78399), [@rikatz](https://github.com/rikatz))

  - the `--cloud-provider-gce-lb-src-cidrs` flag has been deprecated. This flag will be removed once the GCE Cloud Provider is removed from kube-apiserver. ([#81094](https://github.com/kubernetes/kubernetes/pull/81094), [@andrewsykim](https://github.com/andrewsykim))

* The deprecated `--service-account-private-key-file` flag has been removed from the cloud-controller-manager. The flag is still present and supported in the kube-controller-manager. ([#65182](https://github.com/kubernetes/kubernetes/pull/65182), [@liggitt](https://github.com/liggitt))

* kubectl port-forward no longer supports the deprecated -p <pod-name> flag; the flag itself is unnecessary and should be replaced by just the `<pod-name>`. ([#59705](https://github.com/kubernetes/kubernetes/pull/59705), [@phsiao](https://github.com/phsiao))

 - Kubelet flag `--keep-terminated-pod-volumes` was removed.  This flag was deprecated in 2017. ([#122082](https://github.com/kubernetes/kubernetes/pull/122082), [@carlory](https://github.com/carlory)) [SIG Apps, Node, Storage and Testing]

StreamingProxyRedirects feature and `--redirect-container-streaming` flag are deprecated, and will be removed in a future release. The default behavior (proxy streaming requests through the kubelet) will be the only supported option. If you are setting `--redirect-container-streaming=true`, then you must migrate off this configuration. The flag will no longer be able to be enabled starting in v1.20. If you are not setting the flag, no action is necessary. ([#88290](https://github.com/kubernetes/ku...

  the normal deletion flow, so cluster breaking consequences apply. ([#127513](https://github.com/kubernetes/kubernetes/pull/127513), [@tkashem](https://github.com/tkashem)) [SIG API Machinery, Etcd, Node and Testing]