- API requests to deprecated versions now receive a warning header in the API response, and cause a metric indicating use of a deprecated API to be published:
  - `kubectl` outputs warnings to stderr, and accepts a `--warnings-as-errors` option to treat warnings as fatal errors

    tensorflow::Status instead of a bool. Any callers to this function can be
    converted to a bool by adding .ok() to the call.
*   The C API type `TF_SessionWithGraph` has been renamed to `TF_Session`,
    indicating its preferred use in language bindings for TensorFlow. What was
    previously `TF_Session` has been renamed to `TF_DeprecatedSession`.
*   Renamed `TF_Port` to `TF_Output` in the C API.