$re = '/^(?:19|20)?\d{2}(?!000|500|36[7-9]|3[7-9]\d|86[7-9]|8[7-9]\d)[0-35-8]\d\d\d{4}[vVxX]$/m';
$str = 'Format should be
937962723V
or
937962723X
or any 11 digit number according to the current format.
19345678901x';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php