[@wwwtyro](https://github.com/wwwtyro))

* Check for known manifests during preflight instead of only checking for non-empty manifests directory. This makes the preflight checks less heavy-handed by specifically checking for well-known files (kube-apiserver.yaml, kube-controller-manager.yaml, kube-scheduler.yaml, etcd.yaml) in /etc/kubernetes/manifests instead of simply checking for a non-empty directory. ([#57287](https://github.com/kubernetes/kubernetes/pull/57287), [@mattkelly](https:...

  linking directly to the master branch. This ensures that links reference a
  specific point in time, rather than a document that may change over time.
  
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- `ValidatingAdmissionPolicy` now provides a status field that contains results of type checking the validation expression.
  The type checking is fully informational, and the behavior of the policy is unchanged. ([#115668](https://github.com/kubernetes/kubernetes/pull/115668), [@jiahuif](https://github.com/jiahuif))

  linking directly to the master branch. This ensures that links reference a
  specific point in time, rather than a document that may change over time.
  
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  Please use the following format for linking documentation:
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  linking directly to the master branch. This ensures that links reference a
  specific point in time, rather than a document that may change over time.
  
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  Please use the following format for linking documentation:
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* `kubeadm join` is now blocking on the kubelet performing the TLS Bootstrap properly. Earlier, `kubeadm join` only did the discovery part and exited successfully without checking that the kubelet actually started properly and performed the TLS bootstrap correctly. Now, as kubeadm runs some post-join steps (for example, annotating the Node API object...

- Kubeadm: allow the "certs check-expiration" command to not require the existence of the cluster CA key (ca.key file) when checking the expiration of managed certificates in kubeconfig files. ([#106929](https://github.com/kubernetes/kubernetes/pull/106929), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

* Kubernetes 1.16.5+ now requires go1.13.4+ to build  ([#85019](https://github.com/kubernetes/kubernetes/pull/85019), [@liggitt](https://github.com/liggitt))
* Fix LoadBalancer rule checking so that no unexpected LoadBalancer updates are made ([#85990](https://github.com/kubernetes/kubernetes/pull/85990), [@feiskyer](https://github.com/feiskyer))

- kube-apiserver:

If the capacity is zero or absent, the channel is unbuffered and communication
succeeds only when both a sender and receiver are ready. Otherwise, the channel
is buffered and communication succeeds without blocking if the buffer
is not full (sends) or not empty (receives).
A <code>nil</code> channel is never ready for communication.
</p>

<p>
A channel may be closed with the built-in function