diff --git a/index.php b/index.php
index 5b4eee8b..024b2462 100644
--- a/index.php
+++ b/index.php
@@ -104,6 +104,7 @@ if (isset($_COOKIE[COOKIE_PERSISTENT]) && $database) {
             $_SESSION['user'] = new User();
 
             foreach ($sessions as $session) {
+                /** Column sessions.expires was added in v0.7.1. */
                 $expires = strtotime($session['expires'] ?? date('Y-m-d H:i:s', time() + 1));
 
                 if (time() < $expires) {