diff --git a/classes/loginflow/authcode.php b/classes/loginflow/authcode.php
index 2404e77..d4aca1d 100644
--- a/classes/loginflow/authcode.php
+++ b/classes/loginflow/authcode.php
@@ -327,13 +327,14 @@ protected function handlelogin($oidcuniqid, $authparams, $tokenparams, $idtoken)
             // Use 'upn' if available for username (Azure-specific), or fall back to lower-case oidcuniqid.
             $username = $idtoken->claim('upn');
             if (empty($username)) {
-                $username = strtolower($oidcuniqid);
+                $username = $oidcuniqid;
             }
             $matchedwith = $this->check_for_matched($username);
             if (!empty($matchedwith)) {
                 $matchedwith->aadupn = $username;
                 throw new \moodle_exception('errorusermatched', 'local_o365', null, $matchedwith);
             }
+            $username = trim(\core_text::strtolower($username));
             $tokenrec = $this->createtoken($oidcuniqid, $username, $authparams, $tokenparams, $idtoken);
         }
 
diff --git a/db/upgrade.php b/db/upgrade.php
index 933e57e..28dc280 100644
--- a/db/upgrade.php
+++ b/db/upgrade.php
@@ -132,5 +132,20 @@ function xmldb_auth_oidc_upgrade($oldversion) {
         upgrade_plugin_savepoint($result, '2015011615', 'auth', 'oidc');
     }
 
+    if ($result && $oldversion < 2015011627.01) {
+        // Ensure the username field in auth_oidc_token is lowercase.
+        $authtokensrs = $DB->get_recordset('auth_oidc_token');
+        foreach ($authtokensrs as $authtokenrec) {
+            $newusername = trim(\core_text::strtolower($authtokenrec->username));
+            if ($newusername !== $authtokenrec->username) {
+                $updatedrec = new \stdClass;
+                $updatedrec->id = $authtokenrec->id;
+                $updatedrec->username = $newusername;
+                $DB->update_record('auth_oidc_token', $updatedrec);
+            }
+        }
+        upgrade_plugin_savepoint($result, '2015011627.01', 'auth', 'oidc');
+    }
+
     return $result;
 }
diff --git a/version.php b/version.php
index 4782d39..734a8dd 100644
--- a/version.php
+++ b/version.php
@@ -23,7 +23,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version = 2015011627;
+$plugin->version = 2015011627.01;
 $plugin->requires = 2014051200;
 $plugin->component = 'auth_oidc';
 $plugin->maturity = MATURITY_STABLE;