migration of data between different storage engines.  You must stop the API
from writing to etcd during an etcd2 -> etcd3 migration.  HA installations cannot
be migrated at the current time using the official Kubernetes procedure.

1.6 will also default to protobuf encoding if using etcd3.  **This change is
irreversible.**  To rollback, you must restore from a backup made before the

- Contextual logging is now in beta and enabled by default. Check out the [KEP](https://github.com/kubernetes/enhancements/issues/3077) and [official documentation](https://kubernetes.io/docs/concepts/cluster-administration/system-logs/#contextual-logging) for more details. ([#122589](https://github.com/kubernetes/kubernetes/pull/122589), [@pohly](https://github.com/pohly))

- Generating informers for packages in directories containing dots in their name is broken. This will be fixed in v1.16.1. ([#82860](https://github.com/kubernetes/kubernetes/issues/82860))