* Protobuf serialization does not distinguish between `[]` and `null`.
API fields previously capable of storing and returning either `[]` and `null` via JSON API requests (for example, the Endpoints `subsets` field)
can now store only `null` when created using the protobuf content-type or stored in etcd using protobuf serialization (the default in 1.6).

    * API fields previously capable of storing and returning either `[]` and `null` via JSON API requests (for example, the Endpoints `subsets` field) can now store only `null` when created using the protobuf content-type or stored in etcd using protobuf serialization (the default in 1.6+). JSON API clients should tolerate `null` values for such fields, and treat `null` and `[]` as equivalent...

    * API fields previously capable of storing and returning either `[]` and `null` via JSON API requests (for example, the Endpoints `subsets` field) can now store only `null` when created using the protobuf content-type or stored in etcd using protobuf serialization (the default in 1.6+). JSON API clients should tolerate `null` values for such fields, and treat `null` and `[]` as equivalent...

As of Kubernetes 1.19, bugfix support via patch releases for a Kubernetes minor release has increased from 9 months to 1 year.

A survey conducted in early 2019 by the working group (WG) Long Term Support (LTS) showed that a significant subset of Kubernetes end-users fail to upgrade within the previous 9-month support period. 
A yearly support period provides the cushion end-users appear to desire, and is more in harmony with familiar annual planning cycles.

    * This helps to more easily solve use cases like:
        * Reading a body before and/or after a request (equivalent to a middleware).
        * Run middleware-like code only for a subset of *path operations*.
        * Process a request before passing it to a *path operation function*. E.g. decompressing, deserializing, etc.