---
upgrade:
  - |
    Injected network templates will now ignore the ``use_ipv6`` config option.

    Nova supports file injection of network templates. Putting these in a
    config drive is the only way to configure networking without DHCP.

    Previously, setting the ``use_ipv6`` config option to ``False`` prevented
    the generation of IPv6 network info, even if there were IPv6 networks
    available. This was fine when using nova-network, where the same config
    option is used to control generation of these subnets. However, a mismatch
    between this nova option and equivalent IPv6 options in neutron would
    have resulted in IPv6 packets being dropped.

    Seeing as there was no apparent reason for not including IPv6 network info
    when IPv6 capable networks are present, we now ignore this option.
    Instead, we include info for all available networks in the template, be
    they IPv4 or IPv6.