The normality conjecture for cut polytopes

Let $G(V,E)$ be a graph, and let $\operatorname{Cut}^\square(G)$ be the convex hull of the cut points $\delta_{A\vert B}\in\mathbb{R}^{\lvert E\rvert}$ over all unordered vertex partitions $A\vert B$ of $G$. A polytope is normal if every lattice point in $kP$ is a sum of $k$ lattice points from $P$ for every $k\in\mathbb{N}$. Normality conjecture for cut polytopes. The cut polytope $\operatorname{Cut}^\square(G)$ is normal if and only if the graph $G$ has no $K_5$ minor. This is described as the most well-known conjecture in the area and concerns the relationship between normality of cut polytopes and the graph-minor structure of $G$. The supplied text does not state whether the conjecture has been resolved.