Top panel: path on the sky of the white dwarf lens star Stein 2051 B (WD 0426+588), and five source stars in the microlensing events ME10-ME14, over the time baseline of an extended Gaia mission. The coordinate axes are measured relative to (α_ref,L, δ_ref,L). Middle panel: time-evolution of the normalised source-lens separation u for each microlensing event. Bottom panel: time-evolution of the deflection θ₂ (mas) of the major source image. The horizontal black line indicates the astrometric precision limit of 0.131 mas from Sect. 4.2.5.