source/php/Entity/PostManager.php
public function removeEmpty($metaValue)
    {
        if (is_array($metaValue)) {
            return $metaValue;
        }

        return ($metaValue !== null && $metaValue !== false && $metaValue !== '');
    }
public function removeEmpty($metaValue)
    {
        if (is_array($metaValue)) {
            return $metaValue;
        }

        return ($metaValue !== null && $metaValue !== false && $metaValue !== '');
    }
Remove all values that are empty, except the value 0
@param  $metaValue
@return $metaValue