diff --git a/Gemfile b/Gemfile
index 0c1a66d..da93801 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,5 @@
 source "https://rubygems.org"
 
 gem "json"
-gem "rack"
+gem "rack", ">= 2.0.9.1"
 gem "unicorn"