Evolution of the flux and spectral parameters of V404 Cyg during the June 2015 flaring episodes. Panel a) source flux (20–200 keV) in units of 10^-8 erg cm^-2 s^-1. Panels b), c), d) nthcomp fitting parameters (power-law index, Γ, electron temperature, T_e and ). Panels e), f), g) compps fitting parameters (optical depth, τ, electron temperature, T_e  and ). Green, blue and red symbols are used to highlight the best-fitting model, according to our model selection criteria (Sect. 2.2). Blue: comptonization models with constrained T_e (Fig. 1a) further divided into hard (Γ ≤ 1.7; dark blue) and soft spectra (Γ > 1.7; light blue). Green: comptonization models with unconstrained T_e (Fig. 1b). Red: comptonization models with p–value <0.05 fits. (Fig. 1c); ≳ 2 values are only obtained during the X-ray plateaus observed at F_x ~ 5 × 10^-8 erg cm^-2 s^-1.