- kube-apiserver `--admission-control-config-file` files are now validated strictly (EnableStrict). Duplicate and unknown fields in the configuration will now cause an error. ([#128013](https://github.com/kubernetes/kubernetes/pull/128013), [@seans3](https://github.com/seans3))

  which took advantage of subdomain validation (by having dots in the name) can't
  possibly have worked, because we eventually set `pod.spec.hostname` from the `StatefulSetName`,
  and that is validated as a DNS label. ([#114172](https://github.com/kubernetes/kubernetes/pull/114172), [@thockin](https://github.com/thockin))

- Pod Affinity/AntiAffinity label selectors are now validated in the pod affinity score plugin ([#93758](https://github.com/kubernetes/kubernetes/pull/93758), [@damemi](https://github.com/damemi)) [SIG Scheduling]

- The minimum value validation of ReplicationController's `replicas` and `minReadySeconds` fields have been migrated to declarative validation. The requiredness of both fields is also declaratively validated.
  If the `DeclarativeValidation` feature gate is enabled, mismatches with existing validation are reported via metrics.

- Kubeadm now propagates proxy environment variables to kube-proxy ([#84559](https://github.com/kubernetes/kubernetes/pull/84559), [@yastij](https://github.com/yastij))
- Update the latest validated version of Docker to 19.03 ([#84476](https://github.com/kubernetes/kubernetes/pull/84476), [@neolit123](https://github.com/neolit123))

    You can disable CRI explicitly (`--enable-cri=false`) as a
    temporary workaround.
      * The standard `bridge` plugin have been validated to interoperate with
         the new CRI + CNI code path.
      * If you are using plugins other than `bridge`, make sure you have
        updated custom plugins to the latest version that is compatible.

    * 4. Max 20 bit for range (min network bits `<v6>/108` or <v4>/12)
    * kube-controller-manager: convert service CIDR to list `--service-cluster-ip-range=<CIDR>,<CIDR>` and make sure `IPv6DualStack` feature flag is turned on. The flag is validated as above.
    * + to use:

Continuous integration builds use Docker versions 1.11.2, 1.12.6, 1.13.1,
and 17.03.2. These versions were validated on Kubernetes 1.8. However,
consult an appropriate installation or upgrade guide before deciding what
versions of Docker to use.

- Docker 1.13.1 and 17.03.2

    - Shared PID namespace, live-restore, and overlay2 were validated.

    - **Known issues**

### SIG Storage

Google Cloud required that workloads (e.g. Deployments, DaemonSets, etc.) which used `PersistentDisk` volumes were using them in read-only mode.  This validation provided very little value at relatively host implementation cost, and will no longer be validated.  If this is a problem for a specific use-case, please set the `SkipReadOnlyValidationGCE` gate to false to re-enable the validation, and file a Kubernetes bug with details. ([#121083](https://github.com/kubernetes/kubernetes/pull/121083), [@tho...