Left: a range of mixed mode frequencies is shown for different evolutionary stages along the subgiant phase (and early RGB). The individual stages are indicated on the evolutionary track plotted in the right panel. Purple dots represent the individual frequencies of mixed modes, with the shade of the dots allowing to visualise the evolution of the mixed-mode order n_pg. Squares represent the frequency of the ℓ = 1 g-dominated mode closest to ν_max for each evolutionary stage. We refer to Fig. 5 for the determination of this frequency. Middle: magnetic splitting of ℓ = 1, m = 1 mixed modes located inside the range [ν_max − 7Δν : ν_max + 7Δν] for each of the evolutionary stages denoted in the right panel. Squares represent the frequency of the ℓ = 1 g-dominated mode closest to ν_max (see Fig. 5 for further reference). Right: Hertzsprung-Russell diagram of a M_⋆ = 1.5 M_⊙, Z = 0.02 star evolving on the subgiant phase. Coloured stars indicate the different evolutionary stages represented in the other panels.