use warnings;
use strict;
use DateTime;
use DateTime::Format::Human::Duration;

my $now = DateTime->new( time_zone => "UTC",
	year => 2019, month => 6, day => 10 );

my $fmt = DateTime::Format::Human::Duration->new();

for my $mon ( 4, 6, 8 ) {
	for my $day ( 1, 9 , 10, 11, 19 ) {
		my $date = DateTime->new( time_zone => "UTC",
			year => 2019, month => $mon, day => $day );
		my $delta = $now->delta_md($date);
		my ($months,$days) = $delta->in_units(qw/ months days /);
		
		print $now->ymd, " to ", $date->ymd, " is ",
			$fmt->format_duration($delta,
				units=>[qw/months days/]); 
		
		if ( $date>$now && ( $months>2 || $months==2 && $days>0 ) ) {
			print " *** Alert ***";
		}
		print "\n";
	}
}

__END__

2019-06-10 to 2019-04-01 is 2 months and 9 days
2019-06-10 to 2019-04-09 is 2 months and 1 day
2019-06-10 to 2019-04-10 is 2 months
2019-06-10 to 2019-04-11 is 1 month and 29 days
2019-06-10 to 2019-04-19 is 1 month and 21 days
2019-06-10 to 2019-06-01 is 9 days
2019-06-10 to 2019-06-09 is 1 day
2019-06-10 to 2019-06-10 is no time
2019-06-10 to 2019-06-11 is 1 day
2019-06-10 to 2019-06-19 is 9 days
2019-06-10 to 2019-08-01 is 1 month and 21 days
2019-06-10 to 2019-08-09 is 1 month and 29 days
2019-06-10 to 2019-08-10 is 2 months
2019-06-10 to 2019-08-11 is 2 months and 1 day *** Alert ***
2019-06-10 to 2019-08-19 is 2 months and 9 days *** Alert ***