and, maybe...

use feature qw(say);
while (<TESTFILE>){
   next if !~ m/^To\s*=\s*(.*)/;
   say "To = <$1>";
}
[download]

instead:

foreach $Line (<TESTFILE>) {
    if ($Line =~ m/To\s*=\s*(.*)/) {
        $To            = $1;
        print "To = <$To>\n";
    }
}
[download]