Percentage difference for the convergence (on the left) and the shear (on the right) distributions derived from our new reference lens model and that by B21. To generate these maps 500 random realizations of the lens models were used by extracting samples of free parameter values from the MCMC chains (for a detailed description of how the maps are created, see Sect. 4). Contour levels correspond to values of −5%, 5% and −10%, 10%, respectively. These are the limits of the plot color bars. The observed positions of the 237 multiple images used to constrain the lens model are shown as red or white crosses.