- Kubelet config file will be backed up to `/etc/kubernetes/tmp/` folder with `kubeadm-kubelet-config` append with a random suffix as the filename ([#114695](https://github.com/kubernetes/kubernetes/pull/114695), [@chendave](https://github.com/chendave)) [SIG Cluster Lifecycle]
- Kubelet no longer creates certain legacy iptables rules by default.

- The deprecated flag `--lock-object-namespace` and `--lock-object-name` have been removed from kube-scheduler. Please use `--leader-elect-resource-namespace` and `--leader-elect-resource-name` or ComponentConfig instead to configure those parameters. ([#119130](https://github.com/kubernetes/kubernetes/pull/119130), [@SataQiu](https://github.com/SataQiu)) [SIG Scheduling]

- Client-go: Optimized leaders renewing leases by updating leader lock optimistically without getting the record from the API server first. Also, a new metric `leader_election_slowpath_total` was added to allow users to monitor how many leader elections are updated non-optimistically.

  - A `create` or `update` API request with duplicate items in a keyed list no longer wipes out managedFields. Examples include env var entries with the same name, or port entries with the same containerPort in a pod spec.
  - A server-side apply request that makes unrelated changes to an object which has duplicate items in a keyed list no longer fails, and leaves the existing duplicate items as-is.

- Kube-apiserver: redirect responses are no longer returned from backends by default. Set `--aggregator-reject-forwarding-redirect=false` to continue forwarding redirect responses. ([#112193](https://github.com/kubernetes/kubernetes/pull/112193), [@jindijamie](https://github.com/jindijamie)) [SIG API Machinery and Testing]