Planar families of periodic orbits in 4/1 MMR for planetary mass ratio ρ = 0.49 of Kepler-108, which evolves close to this MMR. The black evolution corresponds to the mean anomalies taken by the planar configuration (0, π), while the cyan one is yielded by the angles of the configuration (0,0). The orange evolution corresponds to the calculated observational mean anomalies M_b = −110.226° and M_c = 133.58°.