DHCP v4&v6 DDNS missing options
After revision 391d63da the dhcpv6 server settings allows the user to chose between allow, deny or ignore client updates. That option is not present in the dhcpv4 server settings, the ignore client updates is hard coded in the config file.
ISC DHCP supports standard DDNS updates since 4.3 https://deepthought.isc.org/article/AA-01091/0/ISC-DHCP-support-for-Standard-DDNS.html ( ddns-update-style standard ). Right now ddns-update-style interim is hard coded into the config files. It could be useful for presenting a new option to the user in dhcpv4 and v6 server settings from witch to choose standard or interim update.