We present RegioSQM20, a new version of RegioSQM 11 , which predicts the regioselectivities of electrophilic aromatic substitution (EAS) reactions by finding the atomic center with the highest proton affinity. The following improvements have been made: The open source semiempirical tight binding program xtb is used instead of the closed source MOPAC program; specifically GFN1-xTB/methanol is used instead of PM3/chloroform. Any low energy tau-tomeric forms of the input molecule are identified and regioselectivity predictions are made for each tautomeric form. The increase in CPU time associated with this capability is offset by pre-screening low energy conformations with the GNFF-xTB force field without significant loss of accuracy. The median CPU time requirements of RegioSQM20 is 49 seconds per molecule on four Intel(R) Xeon(R) CPU X5550 @ 2.67GHz cores, but the computational cost depends heavily on the number of possible reaction sites and number of low energy tautomeric forms. Finally, RegioSQM20 offers a qualitative prediction of the reactivity of each tautomer (low, medium, or high) based on the highest proton affinity, i.e. the energy difference between the unprotonated and most stable protonated form using the most stable tautomer.