if (   $e->{severity} || '' =~ /High/
            && $e->{modified} || '' =~ /($today|$yesterday)/ )
        {

##</code><code>##

if (   defined $e->{severity}
            && defined $e->{modified}
            && $e->{severity} =~ /High/
            && $e->{modified} =~ /($today|$yesterday)/ )
        {