diff --git a/flipped-demos/ch03-saas/sinatra-sessions/Gemfile.lock b/flipped-demos/ch03-saas/sinatra-sessions/Gemfile.lock
index eb606e3..96ec7d1 100644
--- a/flipped-demos/ch03-saas/sinatra-sessions/Gemfile.lock
+++ b/flipped-demos/ch03-saas/sinatra-sessions/Gemfile.lock
@@ -2,7 +2,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     mustermann (1.0.3)
-    rack (2.0.6)
+    rack (2.2.8.1)
     rack-protection (2.0.5)
       rack
     sinatra (2.0.5)