I'm new to HoTT. I've started reading the current version of the HoTT book.
On page 12, it mentions as an open problem whether HoTT + univalence has the “homotopy canonicity” property, i.e., every closed term of natural number type is propositionally equal to a canonical form (as opposed to canonicity, which requires a definitional equality).
I found the page homotopy canonicity on the nLab which mentions an unpublished proof by Kapulkin and Sattler that HoTT + univalence does enjoy homotopy canonicity. However, the talk is from 2019 and I did not find a publication of this proof since then.
What is the state of this conjecture?