- A new /resize subresource was added to request pod resource resizing. Update your k8s client code to utilize the /resize subresource for Pod resizing operations. ([#128266](https://github.com/kubernetes/kubernetes/pull/128266), [@AnishShah](https://github.com/AnishShah)) [SIG API Machinery, Apps, Node and Testing]

- The validation of `replicas` field in the ReplicationController `/scale` subresource has been migrated to declarative validation.
  If the `DeclarativeValidation` feature gate is enabled, mismatches with existing validation are reported via metrics.

- Fixed a bug where `Services` using finalizers may hold onto `ClusterIP` and/or `NodePort` allocated resources for longer than expected if the finalizer is removed using the status subresource. ([#120623](https://github.com/kubernetes/kubernetes/pull/120623), [@aojea](https://github.com/aojea))

- Promoted kubectl `--subresource` flag to stable. ([#130238](https://github.com/kubernetes/kubernetes/pull/130238), [@soltysh](https://github.com/soltysh))

- Added `client-go` support for upgrading subresource fields from client-side to server-side management. ([#123484](https://github.com/kubernetes/kubernetes/pull/123484), [@erikgb](https://github.com/erikgb))

  - `spec.version` is removed in v1; use `spec.versions` instead
  - `spec.validation` is removed in v1; use `spec.versions[*].schema` instead
  - `spec.subresources` is removed in v1; use `spec.versions[*].subresources` instead
  - `spec.additionalPrinterColumns` is removed in v1; use `spec.versions[*].additionalPrinterColumns` instead

    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for
    tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us

     */
    @Override
    protected void processWebInfLib() throws LifecycleException {
        super.processWebInfLib();

        final WebResource[] possibleJars = listResources("/WEB-INF/plugin", false);

        for (final WebResource possibleJar : possibleJars) {
            if (possibleJar.isFile() && possibleJar.getName().endsWith(".jar")) {

- Fixed fake clientset ApplyScale subresource from `status` to `scale`. ([#126073](https://github.com/kubernetes/kubernetes/pull/126073), [@a7i](https://github.com/a7i))

  private enum VarHandleLittleEndianBytesMaker {
    INSTANCE {
      /**
       * Implementation used by non-J2ObjC environments (aside, of course, from those that have
       * supersource for the entirety of {@link AbstractFuture}).
       */
      @Override
      @J2ObjCIncompatible
      @Nullable LittleEndianBytes tryMakeVarHandleLittleEndianBytes() {
        try {