diff --git a/Gemfile b/Gemfile
index 32088ed..7ded845 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,4 +1,4 @@
 # A sample Gemfile
 source "https://rubygems.org"
-gem 'rack', '~> 1.5.2'
+gem 'rack', '~> 2.1.4'
 # gem "rails"
diff --git a/Gemfile.lock b/Gemfile.lock
index bff3bbb..4980585 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,10 +1,10 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    rack (1.5.2)
+    rack (2.1.4)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  rack (~> 1.5.2)
+  rack (~> 2.1.4)