Evolutionary tracks of a 110 M_⊙ star evolved with four different MLT++ parameter combinations. Apart from the changes indicated in the figure legend, default values for all other MLT++ parameters have been used. A negative value of λ₁ implies that the maximum reduction in superadiabaticity is applied throughout the track. The tracks corresponding to the default values of MLT++ and to λ₁ = −1.0 are indistinguishable here and predict unrealistic luminosities.