---
upgrade:
  - |
    The way the ML2 plugin filters out API extensions which are not supported
    by loaded mechanism drivers has changed.
    Before, the API extension was on the list if at least one of the mechanism drivers
    supported it, but now the extension needs to be supported by all the mechanism
    drivers. If at least one of them filters it out, it will be removed from
    the final list of enabled API extensions.
    Currently, only the OVN mechanism driver is filtering out some of the ML2
    API extensions, thus if that mechanism driver is loaded in Neutron with any other
    mechanism driver, the list of the enabled API extensions may be smaller than it
    was before.
