diff --git a/example/zoo-app/Gemfile b/example/zoo-app/Gemfile
index 8438ed97..eb52922c 100644
--- a/example/zoo-app/Gemfile
+++ b/example/zoo-app/Gemfile
@@ -9,5 +9,5 @@ end
 
 gem 'rake'
 
-gem 'rack', '>= 3.0.0'
+gem 'rack', '>= 3.1.5'
 gem 'httparty', '>= 0.21.0'
\ No newline at end of file