Colour-magnitude diagram of M4 with data from the Gaia EDR3 catalogue (Vasiliev & Baumgardt 2021) with the isochrones shown in Fig. 14. The adopted parameters for the isochrones are 12.6 Gyr, Z = 0.0015, (m − M)₀ = 11.35 mag, and A_v = 1.3 mag. The open circles are stars from the Howell et al. (2022) sample. Top-right: Star count histogram on G_mag with a magnitude bin of 0.3 dex along the RGB. Bottom-right: Zoom-in of the RGB bump area.