diff --git a/plugins/cas_auth_unl/migration.php b/plugins/cas_auth_unl/migration.php
index ab9b8ae390ab298c9f7c6e395b5db44da8461128..541e58b21ad748463650a01aa8b13c1748b26946 100644
--- a/plugins/cas_auth_unl/migration.php
+++ b/plugins/cas_auth_unl/migration.php
@@ -6,11 +6,17 @@ require_once __DIR__ . '/../../elgg/vendor/autoload.php';
 $lock_file = __DIR__ . '/migration.lock';
 
 $lock = @file_get_contents($lock_file);
+
+$lock_data = json_decode($lock, true);
+
 if (!$lock) {
-    $lock = 0;
+    $lock_data = array(
+        'last_guid' => 0,
+        'icontime' => 0
+    );
 }
 
-if (!$users = @file_get_contents('http://planetred.unl.edu/sync.php?start='.$lock)) {
+if (!$users = @file_get_contents('https://planetred.unl.edu/sync.php?start='.$lock_data['last_guid'] . '&icontime='.$lock_data['icontime'])) {
     echo 'FAILED TO CONNECT' . PHP_EOL;
     exit();
 }
@@ -86,5 +92,10 @@ foreach ($users as $source_user) {
     $target_user->icontime = time();
     
     //Update the lock file
-    file_put_contents($lock_file, $source_user['guid']);
+    $lock_data = array(
+        'last_guid' => $source_user['guid'],
+        'icontime' => time()
+    );
+    
+    file_put_contents($lock_file, json_encode($lock_data));
 }