Today, we released version 4.5.0 of the authoritative DNS nameserver NSD.
This release fixes a couple of minor bugs and adds IXFR out functionality. With this functionality NSD can respond to IXFR queries and serve IXFR transfers downstream.
It is default disabled, that means it does not store IXFR contents for zones by default. The response on the wire is different, also with IXFR disabled, because it is now supported, and thus also for those zones a reply is served, that no differential data is available.
You can get source packages of this version from the downloads page.