optional string key = 1;

  // Represents a key's relationship to a set of values.
  // Valid operators are In, NotIn, Exists, DoesNotExist. Gt, and Lt.
  optional string operator = 2;

  // An array of string values. If the operator is In or NotIn,
  // the values array must be non-empty. If the operator is Exists or DoesNotExist,

- Kubeadm: added the experimental (alpha) feature gate `EtcdLearnerMode` that allows etcd members to be joined as learner and only then promoted as voting members ([#113318](https://github.com/kubernetes/kubernetes/pull/113318), [@pacoxu](https://github.com/pacoxu))

It is worth noting again that kube-scheduler will use apiVersion `kubescheduler.config.k8s.io/v1alpha1` instead of `componentconfig/v1alpha1` in its configuration files in 1.13.

### SIG Service Catalog

A bug introduced in Kubernetes 1.8 caused the API server to accept a request with incorrect case and coerce it to correct case, but this behaviour has been fixed in 1.11 and the API server will once again be enforcing the correct case. It’s worth noting that during this time, the `kubectl` tool continued to enforce case-sensitive keys, so users that strictly manage resources with `kubectl` will be unaffected by this change. ([#65034](https://github.com/kubernetes/kubernetes/pull/65034), [@caesar...