diff --git a/Gemfile b/Gemfile
index f25fe5c..f31b1b5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-gem 'puma', '~> 3.0.2'
+gem 'puma', '~> 4.3.8'
 gem 'rails', '~> 4.2.0'
 gem 'mysql2', '~> 0.5.2'
 gem 'pg', '~> 0.11'
diff --git a/Gemfile.lock b/Gemfile.lock
index 82fd788..a402cf4 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -186,6 +186,7 @@ GEM
       net-ssh (>= 2.6.5)
     net-ssh (3.2.0)
     newrelic_rpm (3.9.6.257)
+    nio4r (2.5.7)
     nokogiri (1.9.1)
       mini_portile2 (~> 2.4.0)
     oauth2 (1.4.1)
@@ -217,7 +218,8 @@ GEM
     pry-byebug (2.0.0)
       byebug (~> 3.4)
       pry (~> 0.10)
-    puma (3.0.2)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (1.6.11)
     rack-openid (1.3.1)
       rack (>= 1.1.0)
@@ -348,7 +350,7 @@ DEPENDENCIES
   omniauth-openid
   pg (~> 0.11)
   pry-byebug
-  puma (~> 3.0.2)
+  puma (~> 4.3.8)
   rack-oauth2!
   rails (~> 4.2.0)
   rails-dev-tweaks (~> 1.1)