diff --git a/Gemfile b/Gemfile
index d528964..401d2dd 100644
--- a/Gemfile
+++ b/Gemfile
@@ -13,7 +13,7 @@ gem 'rails', '~> 5.1.4'
 # Use postgresql as the database for Active Record
 gem 'pg', '~> 0.18'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index 8da3c75..570fc63 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -251,7 +251,8 @@ GEM
     pry-rails (0.3.6)
       pry (>= 0.10.4)
     public_suffix (3.0.1)
-    puma (3.11.0)
+    puma (4.3.11)
+      nio4r (~> 2.0)
     pundit (1.1.0)
       activesupport (>= 3.0.0)
     rack (2.0.3)
@@ -502,7 +503,7 @@ DEPENDENCIES
   poltergeist
   pry-byebug
   pry-rails
-  puma (~> 3.7)
+  puma (~> 4.3)
   pundit
   rails (~> 5.1.4)
   rails-controller-testing