Update from official release.

uc_stripe.mail.inc

@@ -0,0 +1,62 @@
+<?php
+
+/**
+ * This function returns the default off session authention email text.
+ * @return $text - Email text
+ */
+function _uc_stripe_get_authentication_required_email_text(){
+  $text = t("Dear [user:name],
+
+We were unable to process your subscription payment.
+
+Your financial institution is requesting additional verification before your subscription can be renewed.
+
+Please visit this link to return to our site and complete the verification step.
+
+[uc_stripe:verification-link]
+
+-- [site:name] team
+
+");
+
+  return $text;
+}
+
+/**
+ *
+ * Token callback that adds the authentication link to user mails.
+ *
+ * This function is used by the token_replace() call in uc_stripe_mail() to add
+ * the url to verify payment information
+ *
+ * @param $replacements
+ *   An associative array variable containing mappings from token names to
+ *   values (for use with strtr()).
+ * @param $data
+ *   An associative array of token replacement values.
+ * @param $options
+ *   Unused parameter required by the token_replace() function. */
+function uc_stripe_mail_tokens(&$replacements, $data, $options) {
+  global $base_url;
+  $replacements['[uc_stripe:verification-link]'] = $base_url.'/stripe/authenticate-payment/'.$data['authentication_key'];
+}
+
+/**
+ * Implements hook_mail().
+ *
+ * Send mail and replace token with authenticaion link.
+ */
+function uc_stripe_mail($key, &$message, $params) {
+
+  switch ($key) {
+    case 'authentication_required' :
+
+      $message['subject'] = t('Additional Verification Required to Process Subscription.');
+      $variables = array('user' => $params['user'], 'authentication_key' => $params['hash']);
+
+      $message['body'][]= token_replace($params['body'], $variables, array('language' => language_default(), 'callback' => 'uc_stripe_mail_tokens', 'sanitize' => FALSE, 'clear' => TRUE));
+
+      break;
+  }
+
+}