diff --git a/Gemfile b/Gemfile
index d1b8313..7a17dc3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,7 +5,7 @@ git_source(:github) do |repo_name|
 end
 ruby '2.3.1'
 gem 'rails', '~> 5.1.4'
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'
 gem 'coffee-rails', '~> 4.2'
diff --git a/Gemfile.lock b/Gemfile.lock
index add7aff..326edd1 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -128,7 +128,8 @@ GEM
     pg (0.21.0)
     popper_js (1.14.5)
     public_suffix (3.0.3)
-    puma (3.12.0)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.0.6)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -237,7 +238,7 @@ DEPENDENCIES
   mini_racer
   oj
   pg (~> 0.18)
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.1.4)
   rails_layout
   rdoc