Verstraelen's isoparametricity conjecture for minimal hypersurfaces

Let $M^{n}$ be a closed immersed minimal hypersurface of the unit sphere $\mathbb{S}^{n+1}$ with constant scalar curvature. A hypersurface is isoparametric if it has constant principal curvatures. Verstraelen's conjecture. $M^{n}$ is isoparametric. This is presented as a stronger version of Chern's conjecture, and the source states that all currently known closed minimal hypersurfaces in spheres with constant scalar curvature are isoparametric. The conjecture itself remains open in general.