---
features:
  - The subnet API now includes a new
    use_default_subnetpool attribute.  This attribute can
    be specified on creating a subnet in lieu of a
    subnetpool_id.  The two are mutually exclusive.  If
    it is specified as True, the default subnet pool for
    the requested ip_version will be looked up and used.
    If no default exists, an error will be returned.
deprecations:
  - The default_subnet_pools option is now deprecated and
    will be removed in the Newton release.  The same
    functionality is now provided by setting is_default
    attribute on subnetpools to True using the API or
    client.
fixes:
  - Before Mitaka, when a default subnetpool was defined
    in the configuration, a request to create a subnet
    would fall back to using it if no specific subnet
    pool was specified.  This behavior broke the
    semantics of subnet create calls in this scenario and
    is now considered an API bug.  This bug has been
    fixed so that there is no automatic fallback with the
    presence of a default subnet pool.  Workflows which
    depended on this new behavior will have to be
    modified to set the new use_default_subnetpool
    attribute when creating a subnet.