It used custom types in its declarations instead of standard Python types, but it was still a huge step forward.

It also was one of the first frameworks to generate a custom schema declaring the whole API in JSON.

   ([#123341](https://github.com/kubernetes/kubernetes/pull/123341), [@neolit123](https://github.com/neolit123))
- kubectl `port-forward` over websockets (tunneling SPDY) can now be enabled using an `Alpha` feature flag environment variable: KUBECTL_PORT_FORWARD_WEBSOCKETS=true. The API Server being communicated to must *also* have an `Alpha` feature flag enabled: PortForwardWebsockets.

      }
    }
    ```

 *  New: `MediaType.parameter()` gets a parameter like `boundary` from a media type like
    `multipart/mixed; boundary="abc"`.

 *  New: `Authenticator.JAVA_NET_AUTHENTICATOR` forwards authentication requests to
    `java.net.Authenticator`. This obsoletes `JavaNetAuthenticator` in the `okhttp-urlconnection`
    module.

 *  New: `CertificatePinner` now offers an API for inspecting the configured pins.

    dep ->> operation: Run dependency, e.g. DB session
    opt raise
        operation -->> dep: Raise HTTPException
        dep -->> handler: Auto forward exception
        handler -->> client: HTTP error response
        operation -->> dep: Raise other exception
        dep -->> handler: Auto forward exception
    end
    operation ->> client: Return response to client

- `kubeadm`: now respects user provided `kubeconfig` during discovery process ([#113998](https://github.com/kubernetes/kubernetes/pull/113998), [@SataQiu](https://github.com/SataQiu))
- `kubectl port-forward` now exits with exit code 1 when remote connection is
  lost ([#114460](https://github.com/kubernetes/kubernetes/pull/114460), [@brianpursley](https://github.com/brianpursley))

- `KMSv1` is deprecated and will only receive security updates going forward. Use `KMSv2` instead. In a future release, Set `--feature-gates=KMSv1=true` to use the deprecated KMSv1 feature. ([#119007](https://github.com/kubernetes/kubernetes/pull/119007), [@aramase](https://github.com/aramase))

// PodPortForwardOptions is the query options to a Pod's port forward call
// when using WebSockets.
// The `port` query parameter must specify the port or
// ports (comma separated) to forward over.
// Port forwarding over SPDY does not use these options. It requires the port
// to be passed in the `port` header as part of request.
message PodPortForwardOptions {
  // List of ports to forward
  // Required when using WebSockets

  // DriverName defines the name of the dynamic resource driver that is
  // used for allocation of a ResourceClaim that uses this class.
  //
  // Resource drivers have a unique name in forward domain order
  // (acme.example.com).
  optional string driverName = 2;

  // ParametersRef references an arbitrary separate object that may hold
  // parameters that will be used by the driver when allocating a

- Promoted to conformance a test that verified that `Services` only forward traffic on the port and protocol specified. ([#120069](https://github.com/kubernetes/kubernetes/pull/120069), [@aojea](https://github.com/aojea))