- 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))

- kube-apiserver: a new `--requestheader-uid-headers` flag allows configuring request header authentication to obtain the authenticating user's UID from the specified headers. The suggested value for the new option is `X-Remote-Uid`. When specified, the `kube-system/extension-apiserver-authentication` configmap will include the value in its `.data[requestheader-uid-headers]` field. ([#115834](https://github.com/kubernetes/kubernetes/pull/115834),...

- ServerResources was deprecated in February 2019 (https://github.com/kubernetes/kubernetes/commit/618050e) and now it's being removed and ServerGroupsAndResources is suggested to be used instead ([#107180](https://github.com/kubernetes/kubernetes/pull/107180), [@ardaguclu](https://github.com/ardaguclu))