diff --git a/example/zoo-app/Gemfile b/example/zoo-app/Gemfile
index 61b86165..aac51b11 100644
--- a/example/zoo-app/Gemfile
+++ b/example/zoo-app/Gemfile
@@ -9,4 +9,4 @@ end
 
 gem 'rake'
 gem 'rack', '~>2.2'
-gem 'httparty'
+gem 'httparty', '>= 0.21.0'