diff --git a/Gemfile b/Gemfile
index ff2ba1598cc..13ba524d1d7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -120,8 +120,8 @@ gem 'diffy', '~> 3.0.3'
 
 # Application server
 group :unicorn do
-  gem 'unicorn', '~> 4.9.0'
-  gem 'unicorn-worker-killer', '~> 0.4.2'
+  gem 'unicorn', '~> 5.1.0'
+  gem 'unicorn-worker-killer', '~> 0.4.4'
 end
 
 # State machine
diff --git a/Gemfile.lock b/Gemfile.lock
index 396e692847b..2a2f4d56dbe 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -553,7 +553,7 @@ GEM
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rainbow (2.1.0)
-    raindrops (0.15.0)
+    raindrops (0.17.0)
     rake (10.5.0)
     rb-fsevent (0.9.6)
     rb-inotify (0.9.5)
@@ -759,9 +759,8 @@ GEM
       unf_ext
     unf_ext (0.0.7.2)
     unicode-display_width (1.1.1)
-    unicorn (4.9.0)
+    unicorn (5.1.0)
       kgio (~> 2.6)
-      rack
       raindrops (~> 0.7)
     unicorn-worker-killer (0.4.4)
       get_process_mem (~> 0)
@@ -979,8 +978,8 @@ DEPENDENCIES
   uglifier (~> 2.7.2)
   underscore-rails (~> 1.8.0)
   unf (~> 0.1.4)
-  unicorn (~> 4.9.0)
-  unicorn-worker-killer (~> 0.4.2)
+  unicorn (~> 5.1.0)
+  unicorn-worker-killer (~> 0.4.4)
   version_sorter (~> 2.1.0)
   virtus (~> 1.0.1)
   vmstat (~> 2.2)