diff --git a/Gemfile b/Gemfile
index ca4a53f..a6fed89 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,7 +1,7 @@
 source "https://rubygems.org/"
 ruby "2.3.1"
 
-gem 'sinatra'
+gem 'sinatra', '~> 2.0.3'
 gem 'haml'
 gem 'data_mapper'
 gem 'dm-postgres-adapter'
diff --git a/Gemfile.lock b/Gemfile.lock
index d106f7d..0cd957a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -63,7 +63,7 @@ GEM
     kgio (2.11.2)
     mini_portile2 (2.3.0)
     multi_json (1.13.1)
-    mustermann (1.0.2)
+    mustermann (1.0.3)
     nokogiri (1.8.2)
       mini_portile2 (~> 2.3.0)
     pg (1.0.0)
@@ -71,15 +71,15 @@ GEM
     rack (2.0.4)
     rack-flash3 (1.0.5)
       rack
-    rack-protection (2.0.1)
+    rack-protection (2.0.3)
       rack
     raindrops (0.19.0)
     shotgun (0.9.2)
       rack (>= 1.0)
-    sinatra (2.0.1)
+    sinatra (2.0.3)
       mustermann (~> 1.0)
       rack (~> 2.0)
-      rack-protection (= 2.0.1)
+      rack-protection (= 2.0.3)
       tilt (~> 2.0)
     stringex (1.5.1)
     temple (0.8.0)
@@ -100,7 +100,7 @@ DEPENDENCIES
   pg
   rack-flash3
   shotgun
-  sinatra
+  sinatra (~> 2.0.3)
   unicorn
 
 RUBY VERSION