---
features:
  - |
    Microversion 2.91 adds the optional parameter ``host`` to
    the ``unshelve`` server action API.
    Specifying a destination host is only
    allowed to admin users and server status must be ``SHELVED_OFFLOADED``
    otherwise a HTTP 400 (bad request) response is returned.
    It also allows to set ``availability_zone`` to None to unpin a server
    from an availability_zone.
