diff --git a/flipped-demos/ch03-saas/ttt/Gemfile.lock b/flipped-demos/ch03-saas/ttt/Gemfile.lock
index 5899db1..3efb65e 100644
--- a/flipped-demos/ch03-saas/ttt/Gemfile.lock
+++ b/flipped-demos/ch03-saas/ttt/Gemfile.lock
@@ -63,7 +63,7 @@ GEM
       racc (~> 1.4)
     public_suffix (5.0.0)
     racc (1.6.0)
-    rack (2.2.4)
+    rack (2.2.8.1)
     rack-protection (2.2.2)
       rack
     rack-test (2.0.2)