- [Kubernetes v1.15 Release Notes](#kubernetes-v115-release-notes)
  - [1.15 What’s New](#115-what’s-new)
    - [Continuous Improvement](#continuous-improvement)
    - [Extensibility](#extensibility)
  - [Extensibility around core Kubernetes APIs](#extensibility-around-core-kubernetes-apis)
    - [CustomResourceDefinitions Pruning](#customresourcedefinitions-pruning)
    - [CustomResourceDefinition Defaulting](#customresourcedefinition-defaulting)

## **Major Themes**

Kubernetes 1.7 is a milestone release that adds security, stateful application, and extensibility features motivated by widespread production use of Kubernetes.

- The members name and typeDescription of the Reflector struct were exported to allow for better user extensibility. ([#127663](https://github.com/kubernetes/kubernetes/pull/127663), [@alexanderstephan](https://github.com/alexanderstephan))

#### CLI Changes

- [alpha] `kubectl` plugins: `kubectl` now allows binary extensibility. You can extend the default set of `kubectl` commands by writing plugins
  that provide new subcommands. Refer to the documentation for more information.

- `kubectl rollout` and `rollback` now support StatefulSet.

[Special Interest Groups](https://github.com/kubernetes/community/blob/master/sig-list.md), which provide the themes that guide their work. For the 1.9 release, these themes included:

### API Machinery

Extensibility. SIG API Machinery added a new class of admission control webhooks (mutating), and brought the admission control webhooks to beta.

### Apps

### SIG CLI

SIG CLI's main focus this release was on refactoring `kubectl` internals to improve composability, readability and testability of `kubectl` commands. Those refactors will allow the team to extract a mechanism for extensibility of kubectl -- that is, plugins -- in the next releases.

### SIG Cluster Lifecycle

- **Admission webhooks:** Admission webhooks are in widespread use as a Kubernetes extensibility mechanism and have been available in beta since the 1.9 release. The 1.16 release marks the graduation of admission webhooks to general availability (GA).