---
upgrade:
  - |
    To resolve `bug 1805659`_ the default value of
    ``[notifications]/notification_format`` is changed from ``both`` to
    ``unversioned``. For more information see the `documentation of the config
    option`_. If you are using versioned notifications, you will need to adjust
    your config to ``versioned``"

    .. _`bug 1805659`: https://bugs.launchpad.net/nova/+bug/1805659
    .. _`documentation of the config option`: https://docs.openstack.org/nova/latest/configuration/config.html#notifications.notification_format
