---
fixes:
  - |
    Resolved an issue whereby providing an empty list for the ``policies``
    field in the request body of the ``POST /os-server-groups`` API would
    result in a server error. This only affects the 2.1 to 2.63 microversions,
    as the 2.64 microversion replaces the ``policies`` list field with a
    ``policy`` string field. See `bug #1894966`__ for more information.

    .. __: https://bugs.launchpad.net/nova/+bug/1894966