- Kubeadm: updated the supported etcd version to v3.5.23 for supported control plane versions v1.31, v1.32, and v1.33. ([#134692](https://github.com/kubernetes/kubernetes/pull/134692), [@joshjms](https://github.com/joshjms)) [SIG Cluster Lifecycle and Etcd]

knowledge.  `Just think of what work it would make with the day
and night!  You see the earth takes twenty-four hours to turn
round on its axis--'

  `Talking of axes,' said the Duchess, `chop off her head!'

  Alice glanced rather anxiously at the cook, to see if she meant
to take the hint; but the cook was busily stirring the soup, and
seemed not to be listening, so she went on again:  `Twenty-four
hours, I THINK; or is it twelve?  I--'

   * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
   * syntax</a>.
   *
   * @param map the mappings to be placed in the new map
   * @return a new {@code HashMap} initialized with the mappings from {@code map}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call

   * href="https://docs.oracle.com/javase/tutorial/java/generics/genTypeInference.html#type-inference-instantiation">"diamond"
   * syntax</a>.
   *
   * @param map the mappings to be placed in the new map
   * @return a new {@code HashMap} initialized with the mappings from {@code map}
   */
  @SuppressWarnings("NonApiType") // acts as a direct substitute for a constructor call

are hence enabled by default. This will be fixed in a future release.
[#38593](https://github.com/kubernetes/kubernetes/issues/38593)
* Federation control plane can be upgraded by updating the image
fields in the `Deployment` specs of the control plane components.
However, federation control plane upgrades were not tested in this
release [38537](https://github.com/kubernetes/kubernetes/issues/38537)

## Notable Changes to Existing Behavior

* Action required: If you have a running federation control plane, you will have to ensure that for all federation resources, the corresponding namespace exists in federation control plane. ([#31139](https://github.com/kubernetes/kubernetes/pull/31139), [@nikhiljindal](https://github.com/nikhiljindal))