gwst/includes/update-email.php

<?php
if (isset($_SESSION['userid'])) {
    include_once ('verifications.php');
    $updmail = $con->prepare("UPDATE userinfo SET usermail = ? WHERE userid = ?");
    $updmail->bind_param("si", $_POST['useremail'], $_SESSION['userid']);
    $updmail->execute();
    $_SESSION['usermail'] = $_POST['useremail'];
    echo 'E-mail address updated.<br />';
}
?>