$ perl -MDateTime -E 'say $DateTime::VERSION'
1.33

$ perl -MDateTime -E '
my $dt = DateTime->new( time_zone => "UTC",
year => 2016,
month => 12,
day => 31,
hour => 23,
minute => 59,
second => 60
);
say $dt->datetime;
$dt->add( months => 1 );
say $dt->datetime;
'
Invalid second value (60)
 at -e line 2.