* If you used the [PodDisruptionBudget](http://kubernetes.io/docs/admin/disruptions/) feature in 1.4 (i.e. created `PodDisruptionBudget` objects), then **BEFORE**  upgrading from 1.4 to 1.5, you must delete all `PodDisruptionBudget` objects (`policy/v1alpha1/PodDisruptionBudget`) that you have created. It is not possible to delete these objects after you upgrade, and their presence will prevent you from using the beta PodDisruptionBudget feature in 1.5 (which uses `policy/v1beta1/PodDisruptionBudget`)....

API

* **Replication controller & Replicaset**: the DELETE request of a replication controller or a replicaset becomes asynchronous by default. The object will continue to exist in the key-value store for some time. The API server will set its metadata.deletionTimestamp, add the "orphan" finalizer to its metadata.finalizers. The object will be deleted from the key-value store after the garbage collector orphans its dependents. Please refer to this [user-guide](http://kubernetes.io/docs/us...

- Added to `MutableFeatureGate` the ability to override the default setting of feature gates, to allow default-enabling...