diff --git a/application/config/migration.php b/application/config/migration.php
index f3d00a07..55936868 100644
--- a/application/config/migration.php
+++ b/application/config/migration.php
@@ -22,7 +22,7 @@ $config['migration_enabled'] = TRUE;
 |
 */
 
-$config['migration_version'] = 158;
+$config['migration_version'] = 159;
 
 /*
 |--------------------------------------------------------------------------
diff --git a/application/migrations/159_extend_default_qsl.php b/application/migrations/159_extend_default_qsl.php
new file mode 100644
index 00000000..768b48f4
--- /dev/null
+++ b/application/migrations/159_extend_default_qsl.php
@@ -0,0 +1,11 @@
+<?php
+
+// Create migration that makes the submode column in the logbook table an index
+class Migration_extend_default_qsl  extends CI_Migration {
+
+    public function up() {
+        $this->db->query("ALTER TABLE `users` CHANGE COLUMN `user_default_confirmation` `user_default_confirmation` VARCHAR(4) NULL DEFAULT NULL");
+    }
+}
+
+?>