<!-- Collection of code snippets by Arne Vajhøj -->
<!-- posted to eksperten.dk, usenet and other places (2002-now) -->
<?php
function test($dstr) {
    $dt = new DateTime($dstr);
    $now = new DateTime();
    $dtplus = $dt->add(new DateInterval('P2M'));
    return $dtplus->getTimeStamp() > $now->getTimeStamp();
}

echo test('2018-01-06') ? 'Y' : 'N';
echo test('2018-01-02') ? 'Y' : 'N';
?>