- A server-side apply request that changes an object which has duplicate items in a keyed list, and modifies the duplicated item removes the duplicates and replaces them with the single item contained in the server-side apply request. ([#121575](https://github.com/kubernetes/kubernetes/pull/121575), [@apelisse](https://github.com/apelisse))

* Made multi-scheduler graduated to Beta and then v1. ([#38871](https://github.com/kubernetes/kubernetes/pull/38871), [@k82cn](https://github.com/k82cn))
* Fixed forming resolver search line for pods: exclude duplicates, obey libc limitations, logging and eventing appropriately. ([#29666](https://github.com/kubernetes/kubernetes/pull/29666), [@vefimova](https://github.com/vefimova))

* The Rackspace cloud provider has been removed after a long deprecation period. It was deprecated because it duplicates a lot of the OpenStack logic and can no longer be maintained. Please use the OpenStack cloud provider instead. ([#52855](https://github.com/kubernetes/kubernetes/pull/52855), [@NickrenREN](https://github.com/NickrenREN))

- kube-apiserver `--admission-control-config-file` files are now validated strictly (EnableStrict). Duplicate and unknown fields in the configuration will now cause an error. ([#128013](https://github.com/kubernetes/kubernetes/pull/128013), [@seans3](https://github.com/seans3))

- kube-proxy: a configuration file specified via `--config` is now loaded with strict deserialization, which fails if the config file contains duplicate or unknown fields. This protects against accidentally running with config files that are malformed, mis-indented, or have typos in field names, and getting unexpected behavior. ([#82927](https://github.com/kubernetes/kubernetes/pull/82927), [@ob...

* [fluentd-gcp addon] Update Stackdriver plugin to version 0.6.7 ([#52565](https://github.com/kubernetes/kubernetes/pull/52565), [@crassirostris](https://github.com/crassirostris))
* Fixes an issue with RBAC reconciliation that could cause duplicated subjects in some bootstrapped rolebindings on each restart of the API server. ([#53239](https://github.com/kubernetes/kubernetes/pull/53239), [@enj](https://github.com/enj))

- Manual change of a failed job condition status to False does not result in duplicate conditions ([#110292](https://github.com/kubernetes/kubernetes/pull/110292), [@mimowo](https://github.com/mimowo)) [SIG Apps]
- OpenAPI will no longer duplicate these schemas:
  - io.k8s.apimachinery.pkg.apis.meta.v1.DeleteOptions_v2
  - io.k8s.apimachinery.pkg.apis.meta.v1.ObjectMeta_v2

* Fixes an issue with RBAC reconciliation that could cause duplicated subjects in some bootstrapped rolebindings on each restart of the API server. ([#53239](https://github.com/kubernetes/kubernetes/pull/53239), [@enj](https://github.com/enj))

- KEP-1880: Users of the new feature to add multiple service CIDR will use by default a dual-write strategy on the new ClusterIP allocators to avoid the problem of possible duplicate IPs allocated to Services when running skewed kube-apiservers using different allocators. They can opt-out of this behavior by enabled the feature gate DisableAllocatorDualWrite. ([#122047](https://github.com/kubernetes/kubernetes/pull/122047), ...

- Duplicate owner reference entries in create/update/patch requests now get deduplicated by the API server. The client sending the request now receives a warning header in the API response. Clients should stop sending requests with duplicate owner references. The API server may reject such requests as early as 1.24. ([#96185](https://github.com/kubernetes/kubernetes/pull/96185),...