Isaacs–Navarro–Tiep conjecture on Sylow character degrees

Let $G$ be a finite group, let $p$ be a prime, and let $P$ be a Sylow $p$-subgroup of $G$. Isaacs–Navarro–Tiep conjecture. Then

$$|\operatorname{cd}(P)|\le|\operatorname{cd}_p(G)|+1.$$

This strengthens one of the preceding conjectures and is known when $|\operatorname{cd}_p(G)|=2$, but remains open in general.