diff --git a/Gemfile b/Gemfile
index 95d43cd..ab4a3bc 100644
--- a/Gemfile
+++ b/Gemfile
@@ -25,5 +25,5 @@ gem 'rack-robotz', '~> 0.0'
 gem 'rack-anystatus', '~> 0.1'
 
 # Deployment
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 gem 'typekit_domain_manager', '~> 0.1.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index d6d2cf1..b9a68b6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -76,6 +76,7 @@ GEM
     neat (1.7.1)
       bourbon (>= 4.0)
       sass (>= 3.3)
+    nio4r (2.5.2)
     octopress-hooks (2.6.1)
       jekyll (>= 2.0)
     octopress-paginate (1.1.2)
@@ -83,7 +84,8 @@ GEM
     parslet (1.5.0)
       blankslate (~> 2.0)
     posix-spawn (0.3.9)
-    puma (3.12.2)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     pygments.rb (0.6.2)
       posix-spawn (~> 0.3.6)
       yajl-ruby (~> 1.2.0)
@@ -145,7 +147,7 @@ DEPENDENCIES
   kramdown
   neat
   octopress-paginate
-  puma (~> 3.12)
+  puma (~> 4.3)
   rack-anystatus (~> 0.1)
   rack-contrib (~> 1.4)
   rack-rewrite (~> 1.5.0)