Getting the previous day's date is a FAQ. You should find a variety of answers on PM. One way is the following:

# Jan = 1
my ($yest_y, $yest_m, $yest_d) = (
   gmtime(
      timegm(0,0,0,$today_d,$today_m-1,$today_y) - 24*60*60
   )
)[5,4,3];
$yest_m += 1;
$yest_y += 1900;
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Use timegm + gmtime even for local dates.