Left: stability analysis in the plane (e_b, e_d), assuming coplanar orbits. For fixed initial conditions, the parameter space of the system is explored by varying the eccentricities of planets b and d with a step size of 0.0025. Right: stability analysis in the plane (i_c, i_d), assuming i_b = 88.76 deg (Table 5) and the longitude of the node of all planets equal to zero. For fixed initial conditions, the parameter space of the system is explored by varying the inclinations of planets c and d with a step size of 1 deg. The dashed circle corresponds to mutual inclinations with planet b of 60 deg. The color codes are the same as in Fig. 7.