Evolution of (a) E_div/E and (b) |E_mix|/E_J, s and (c) ϵ_force for different NLFF models based on different input data: not preprocessed (light blue circles), standard preprocessed (violet bullets), preprocessed without smoothing (dark blue bullets), preprocessed without smoothing and no nearness to observed data enforced (light blue bullets). (d) Corresponding time evolution of |H_J|/|H_𝒱|. The horizontal dashed line in (a) indicates the nominal threshold of E_div/E = 0.08, an upper limit for the accepted solenoidality of the input magnetic field. The vertical bars show the time span between the nominal GOES start and peak time of the X2.2 (peak time 08:57 UT) and X9.3 flare (peak time 11:53 UT).