Some upgrade methods might upgrade etcd from 3.0 to 3.1 automatically when you upgrade from Kubernetes 1.8, unless you specify otherwise. Because [etcd does not support downgrading](https://coreos.com/etcd/docs/latest/upgrades/upgrade_3_1.html), you'll need to either remain on etcd 3.1 or restore from a backup if you want to downgrade back to Kubernetes 1.8.

- Rev the Azure SDK for networking to 2017-06-01 ([#61955](https://github.com/kubernetes/kubernetes/pull/61955))
- Es-image has been upgraded to Elasticsearch 6.3.2 ([#67484](https://github.com/kubernetes/kubernetes/pull/67484))
- metrics-server has been upgraded to v0.3.1. ([#68746](https://github.com/kubernetes/kubernetes/pull/68746))
- GLBC has been updated to v1.2.3 ([#66793](https://github.com/kubernetes/kubernetes/pull/66793))

* kubeadm upgrade no longer races leading to unexpected upgrade behavior on pod restarts ([#62655](https://github.com/kubernetes/kubernetes/pull/62655), [@stealthybox](https://github.com/stealthybox))
    * kubeadm upgrade now successfully upgrades etcd and the controlplane to use TLS
    * kubeadm upgrade now supports external etcd setups
    * kubeadm upgrade can now rollback and restore etcd after an upgrade failure

- [Kubernetes v1.14 Release Notes](#kubernetes-v114-release-notes)
  - [1.14 What’s New](#114-whats-new)
  - [Known Issues](#known-issues-1)
  - [Urgent Upgrade Notes](#urgent-upgrade-notes)
    - [(No, really, you MUST read this before you upgrade)](#no-really-you-must-read-this-before-you-upgrade)
  - [Deprecations](#deprecations)
  - [Removed and deprecated metrics](#removed-and-deprecated-metrics)
    - [Removed metrics](#removed-metrics)

    - [Node Binaries](#node-binaries-12)
- [Kubernetes 1.13 Release Notes](#kubernetes-113-release-notes)
  - [Security Content](#security-content)
  - [Urgent Upgrade Notes](#urgent-upgrade-notes)
    - [(No, really, you MUST do this before you upgrade)](#no-really-you-must-do-this-before-you-upgrade)
  - [Known Issues](#known-issues)
  - [Deprecations](#deprecations)
  - [Major Themes](#major-themes)
    - [SIG API Machinery](#sig-api-machinery)

* **Tolerations**

    - [Additional Notable Feature Updates](#additional-notable-feature-updates)
  - [Known Issues](#known-issues)
  - [Urgent Upgrade Notes](#urgent-upgrade-notes)
    - [(No, really, you MUST read this before you upgrade)](#no-really-you-must-read-this-before-you-upgrade)
      - [API Machinery](#api-machinery)
      - [Apps](#apps)
      - [Auth](#auth)
      - [AWS](#aws)
      - [Azure](#azure)

    - [Etcd v3.5.[0-2] data corruption](#etcd-v350-2-data-corruption)
  - [Urgent Upgrade Notes](#urgent-upgrade-notes)
    - [(No, really, you MUST read this before you upgrade)](#no-really-you-must-read-this-before-you-upgrade)
  - [Changes by Kind](#changes-by-kind-16)
    - [Deprecation](#deprecation)
    - [API Change](#api-change-2)
    - [Feature](#feature-9)

    - [Node Binaries](#node-binaries-2)
    - [Container Images](#container-images-2)
  - [Changelog since v1.30.0](#changelog-since-v1300)
  - [Urgent Upgrade Notes](#urgent-upgrade-notes)
    - [(No, really, you MUST read this before you upgrade)](#no-really-you-must-read-this-before-you-upgrade)
  - [Changes by Kind](#changes-by-kind-2)
    - [Deprecation](#deprecation-1)
    - [API Change](#api-change-1)
    - [Feature](#feature-2)

  - [Urgent Upgrade Notes](#urgent-upgrade-notes)
    - [(No, really, you MUST read this before you upgrade)](#no-really-you-must-read-this-before-you-upgrade)
  - [Changes by Kind](#changes-by-kind-15)
    - [Deprecation](#deprecation)
    - [API Change](#api-change-4)
    - [Feature](#feature-14)