### Internal Storage Layer

    - [Windows](#windows)
    - [OpenStack](#openstack)
    - [API-machinery](#api-machinery)
    - [Auth](#auth)
    - [Azure](#azure)
    - [CLI](#cli)
    - [Network](#network)
  - [Before Upgrading](#before-upgrading)
  - [Known Issues](#known-issues)
  - [Deprecations](#deprecations)
  - [Other Notable Changes](#other-notable-changes-13)
    - [Apps](#apps)
    - [AWS](#aws)
    - [Auth](#auth-1)

    - [SIG Node](#sig-node)
    - [SIG Network](#sig-network)
    - [SIG Scalability](#sig-scalability)
    - [SIG Scheduling](#sig-scheduling)
    - [SIG Storage](#sig-storage)
  - [Before Upgrading](#before-upgrading)
  - [Known Issues](#known-issues)
  - [Deprecations](#deprecations)
    - [Apps](#apps)
    - [Auth](#auth)
    - [Autoscaling](#autoscaling)
    - [Cluster Lifecycle](#cluster-lifecycle)

    - [SIG OpenStack](#sig-openstack)
    - [SIG Scheduling](#sig-scheduling)
    - [SIG Storage](#sig-storage)
    - [SIG Windows](#sig-windows)
  - [Known Issues](#known-issues)
  - [Before Upgrading](#before-upgrading)
      - [New Deprecations](#new-deprecations)
      - [Removed Deprecations](#removed-deprecations)
      - [Graduated to Stable/GA](#graduated-to-stablega)
      - [Graduated to Beta](#graduated-to-beta)

    - [Client Binaries](#client-binaries-16)
    - [Server Binaries](#server-binaries-16)
    - [Node Binaries](#node-binaries-16)
  - [**Major Themes**](#major-themes)
  - [**Action Required Before Upgrading**](#action-required-before-upgrading)
    - [Network](#network)
    - [Storage](#storage)
    - [API Machinery](#api-machinery)
    - [Controller Manager](#controller-manager)
    - [kubectl (CLI)](#kubectl-cli)

    - [Instrumentation](#instrumentation)
    - [Network](#network)
    - [Node](#node)
    - [OpenStack](#openstack)
    - [Storage](#storage)
    - [Windows](#windows)
  - [Before Upgrading](#before-upgrading)
    - [**API Machinery**](#api-machinery-1)
    - [**Auth**](#auth-1)
    - [**CLI**](#cli)
    - [**Cluster Lifecycle**](#cluster-lifecycle-1)
    - [**Multicluster**](#multicluster)

## Urgent Upgrade Notes

### (No, really, you MUST do this before you upgrade)

Before upgrading to Kubernetes 1.13, you must keep the following in mind:

- kube-apiserver

 - Reduced state change noise when volume expansion fails. Also mark certain failures as infeasible.
  
  ACTION REQUIRED:  If you are using the `RecoverVolumeExpansionFailure` alpha feature gate
  then after upgrading to this release, you need to update some objects.
  For any existing PersistentVolumeClaimss with `status.allocatedResourceStatus` set to either

  
  vSphere releases less than 67u3 are deprecated as of v1.21. Please consider upgrading vSphere to 67u3 or above. vSphere CSI Driver requires minimum vSphere 67u3.
  
  VM Hardware version less than 15 is deprecated as of v1.21. Please consider upgrading the Node VM Hardware version to 15 or above. vSphere CSI Driver recommends Node VM's Hardware version set to at least vmx-15.
  

* Resolves spurious rollouts of workload controllers when upgrading the API server, due to incorrect defaulting of an alpha procMount field in pods ([#78883](https://github.com/kubernetes/kubernetes/pull/78883), [@liggitt](https://github.com/liggitt))