// MaxSkew describes the degree to which pods may be unevenly distributed.
  // When `whenUnsatisfiable=DoNotSchedule`, it is the maximum permitted difference
  // between the number of matching pods in the target topology and the global minimum.
  // The global minimum is the minimum number of matching pods in an eligible domain
  // or zero if the number of eligible domains is less than MinDomains.

- The resource version option, when passed to a list call, is now consistently interpreted as the minimum allowed resource version.  Previously when listing resources that had the watch cache disabled clients could retrieve a snapshot at that exact resource version.  If the client requests a resource version newer than the current state, a TimeoutError...

* In-place node upgrades to this release from versions 1.7.14, 1.8.9, and 1.9.4 are not supported if using subpath volumes with PVCs.  Such pods should be drained from the node first.

* The minimum supported version of Docker is now 1.11; if you are using Docker 1.10 or below, be sure to upgrade Docker before upgrading Kubernetes. ([#57845](https://github.com/kubernetes/kubernetes/pull/57845), [@yujuhong](https://github.com/yujuhong))

  
  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.

### Network

- Reduces the cache TTL for negative responses to 5s minimum. ([#74093](https://github.com/kubernetes/kubernetes/pull/74093), [@blakebarnett](https://github.com/blakebarnett))

### Node

*   The Go version was upgraded from go1.8.3 to **go1.9.2** ([#51375](https://github.com/kubernetes/kubernetes/pull/51375),[ @cblecker](https://github.com/cblecker))
    *   The minimum supported go version bumps to 1.9.1. ([#55301](https://github.com/kubernetes/kubernetes/pull/55301),[ @xiangpengzhao](https://github.com/xiangpengzhao))

* Updated kubeadm's minimum supported kubernetes in v1.11.x to 1.10 ([#63920](https://github.com/kubernetes/kubernetes/pull/63920), [@dixudx](https://github.com/dixudx))

language.
</p>

<p>
A link of the form [<a href="#Language_versions">Go 1.xx</a>] indicates that a described
language feature (or some aspect of it) was changed or added with language version 1.xx and
thus requires at minimum that language version to build.
For details, see the <a href="#Language_versions">linked section</a>
in the <a href="#Appendix">appendix</a>.
</p>

<h2 id="Source_code_representation">Source code representation</h2>

- VSphere releases less than 7.0u2 are deprecated as of v1.24. Please consider upgrading vSphere to 7.0u2 or above. vSphere CSI Driver requires minimum vSphere 7.0u2.

- kubeadm: Bumped the minimum supported Docker version to 1.13.1 ([#77051](https://github.com/kubernetes/kubernetes/pull/77051), [@chenzhiwei](https://github.com/chenzhiwei))