---
features:
  - The ``availability_zone`` extension's API definition is now available
    in ``neutron_lib.api.definitions.availability_zone``.
  - A new API validation type ``type:availability_zone_hint_list`` has been
    added and validates a list of availability zone hints.
  - Exceptions for the ``availability_zone`` are now available in
    ``neutron_lib.exceptions.availability_zone``.
  - The constant ``AZ_HINTS_DB_LEN`` has been added to
    ``neutron_lib.db.constants``.