* Fixed racy panics when using fake watches with ObjectTracker ([#61195](https://github.com/kubernetes/kubernetes/pull/61195), [@grantr](https://github.com/grantr))
* Fixed mounting of UNIX sockets(and other special files) in subpaths ([#61480](https://github.com/kubernetes/kubernetes/pull/61480), [@gnufscied](https://github.com/gnufied))

* PodSpecs containing parent directory references such as `..` (for example, `../bar`) in hostPath volume path or in volumeMount subpaths must be changed to the simple absolute path. Backsteps `..` are no longer allowed.([#47290](https://github.com/kubernetes/kubernetes/pull/47290), [@jhorwit2](https://github.com/jhorwit2)).


### API Machinery

    * - Don't generate empty record for externalName service.
    * - Add validation for upstreamNameserver port.
    * - Update go version to 1.9.3.
* Fix mounting of UNIX sockets(and other special files) in subpaths ([#61480](https://github.com/kubernetes/kubernetes/pull/61480), [@gnufied](https://github.com/gnufied))

* Support new NODE_OS_DISTRIBUTION 'custom' on GCE ([#61235](https://github.com/kubernetes/kubernetes/pull/61235), [@yguo0905](https://github.com/yguo0905))
* Fix mounting of UNIX sockets(and other special files) in subpaths ([#61480](https://github.com/kubernetes/kubernetes/pull/61480), [@gnufied](https://github.com/gnufied))

  If the `subPath` is a file rather than a directory, Pods may fail to start ([#45613](https://github.com/kubernetes/kubernetes/issues/45613)).

  **Do not upgrade to v1.6.3** if your cluster may run Pods with such subPaths.

## Downloads for v1.6.3


filename | sha256 hash
-------- | -----------
[kubernetes.tar.gz](https://dl.k8s.io/v1.6.3/kubernetes.tar.gz) | `0af5914fcea36b3c65c8185f31e94b2839eaed52dfdd666d31dfa14534a7d69c`

* Fix mounting of UNIX sockets(and other special files) in subpaths ([#61480](https://github.com/kubernetes/kubernetes/pull/61480), [@gnufied](https://github.com/gnufied))

    * Implements subPathExpr field for expanding environment variables into a subPath
    * The fields subPathExpr and subPath are mutually exclusive
    * Note: This is a breaking change from the previous version of this alpha feature

* change azure disk host cache to ReadOnly by default ([#72229](https://github.com/kubernetes/kubernetes/pull/72229), [@andyzhangx](https://github.com/andyzhangx))
* Fixes issue with cleaning up stale NFS subpath mounts ([#71804](https://github.com/kubernetes/kubernetes/pull/71804), [@msau42](https://github.com/msau42))

- Make sure auto-mounted subpath mount source is already mounted ([#112499](https://github.com/kubernetes/kubernetes/pull/112499), [@andyzhangx](https://github.com/andyzhangx)) [SIG Storage]

## Dependencies

### Added
_Nothing has changed._

* Fixes issue with cleaning up stale NFS subpath mounts ([#71804](https://github.com/kubernetes/kubernetes/pull/71804), [@msau42](https://github.com/msau42))