Cluster masters running Kubernetes versions 1.6.X will be upgraded to v1.6.9 according to the following schedule:
You can now use IP aliases with an existing subnetwork when creating a cluster. IP aliases are a Beta feature in Container Engine version 1.7.5.
The following flags are now available in gcloud beta containers create for enabling the use of IP aliases with an existing subnetwork: -enable-ip-alias, --cluster-secondary-range-name, --services-secondary-range-name.