* Renamed the API server flag `--experimental-bootstrap-token-auth` to `--enable-bootstrap-token-auth`. The old value is accepted with a warning in 1.8 and will be removed in 1.9. ([#51198](https://github.com/kubernetes/kubernetes/pull/51198), [@mattmoyer](https://github.com/mattmoyer))

- Fixes a panic in kube-controller-manager cleaning up bootstrap tokens ([#82887](https://github.com/kubernetes/kubernetes/pull/82887), [@tedyu](https://github.com/tedyu))

- `cluster-bootstrap`: improved the security of the functions responsible for generation and validation of bootstrap tokens. ([#120400](https://github.com/kubernetes/kubernetes/pull/120400), [@neolit123](https://github.com/neolit123))

- Added...

* When a kubelet is using --bootstrap-kubeconfig and certificate rotation, it no longer waits for bootstrap to succeed before launching static pods. ([#71174](https://github.com/kubernetes/kubernetes/pull/71174), [@smarterclayton](https://github.com/smarterclayton))

- The deprecated `--experimental-bootstrap-kubeconfig` flag has been removed.
  This can be set via `--bootstrap-kubeconfig`. ([#103172](https://github.com/kubernetes/kubernetes/pull/103172), [@niulechuan](https://github.com/niulechuan))

### API Change

- Migrated the bootstrap signer controller and the token cleaner controller (within `kube-controller-manager`) to use [contextual logging](https://k8s.io/docs/concepts/cluster-administration/system-logs/#contextual-logging). ([#113464](https://github.com/kubernetes/kube...

- kubeadm: You can now delete multiple bootstrap tokens at once. ([#75646](https://github.com/kubernetes/kubernetes/pull/75646), [@bart0sh](https://github.com/bart0sh))

- kubeadm: The kubeadm configuration now supports the definition of more than one control plane instances with their own APIEndpoint. The APIEndpoint for the "bootstrap" control plane instance should be defined using `InitConfiguration.APIEndpoint`, while the APIEndpoints for additional control plane instances should be added using `JoinConfiguration.APIEndpoint`. ([#67832](https://github.com/kubernetes/kubernetes/pull/67832),...

- We no longer allow the cluster operator to delete any suggested priority & fairness bootstrap configuration object. If a cluster operator removes a suggested configuration, it will be restored by the apiserver. ([#102067](https://github.com/kubernetes/kubernetes/pull/102067), [@tkashem](https://github.com/tkashem))