$ perl -MDateTime -E 'say $DateTime::VERSION'
1.39

$ 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;
'
2016-12-31T23:59:60
2017-02-01T00:00:00