Odd-Hadwiger conjecture for signed graphs

Let $(G,-)$ be a signed graph whose underlying graph is $G$, with every edge negative, and let $(K_{k+1},-)$ denote the complete graph on $k+1$ vertices with every edge negative. A signed graph $(H,\pi)$ is a minor of $(G,\sigma)$ if it is obtained by deleting vertices or edges, contracting positive edges, and switching. Odd-Hadwiger conjecture. If $(G,-)$ has no $(K_{k+1},-)$-minor, then

$$\chi_c(G,+)\leq k.$$

This conjecture strengthens the Hadwiger conjecture and generalizes Catlin's result, whose case $k=3$ is stated in the source. Its status is not resolved in the supplied material.