Randomized link goes to an except of North Korea's "Korean Central TV" where NK announces their Hwasong-17 launch. It's in music video style, make of that what you will, and seems to contain a fraction of the information at <https://en.wikipedia.org/wiki/Hwasong-17>. It is not clear to me whether this was actually tested with a nuclear warhead, the video doesn't get more concrete than "[this is] a reliable nuclear war deterrence means" which could just mean it deters nuclear war, not that it's nuclear in itself. I don't know whether this supports the claim that it is "really" nothing new.