nicolas.mahy

Thanks for the answer. In the meanwhile, I found a solution:

add_filter( 'wpcf7_validate_number*', 'your_validation_filter_func', 999, 2 );

function your_validation_filter_func( $result, $tag ) {
$type = $tag['type'];
$name = $tag['name'];
if ( 'pincode' == $name ) {
$the_value = $_POST[$name];

        $myresult = $the_value;
        if($myresult!="1234")
        {
	$result->invalidate( $tag, "Deze pincode is niet correct." );
        }

}

return $result;
}