I don't think they stopped the cheating software completely or at all. I think Trump overcame the 2016 algo. They never thought he would get that much turnout. They adjusted their algo for 2020, but had to print many more ballots, aka mail in ballots (using CV-19) in order to match the fake vote with a paper trail. They still underestimated the (much larger) turnout, which resulted in major ballot dumps across all the swing states. They got sloppy and it was obvious to any sane person what happened.