diff --git a/Gemfile b/Gemfile
index 3964661..28b2e5a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ 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'
 gem 'jquery-rails'
diff --git a/Gemfile.lock b/Gemfile.lock
index d2479c7..8940dbf 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -185,7 +185,8 @@ GEM
       byebug (~> 10.0)
       pry (~> 0.10)
     public_suffix (3.0.3)
-    puma (3.12.0)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.0.5)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -305,11 +306,11 @@ DEPENDENCIES
   kaminari (~> 1.1, >= 1.1.1)
   listen (>= 3.0.5, < 3.2)
   mini_magick (~> 4.8)
-  pg (~> 0.18)
   petergate (~> 1.8, >= 1.8.1)
+  pg (~> 0.18)
   platipus (~> 0.1.0)
   pry-byebug
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.1.4)
   redcarpet
   redis (~> 3.3, >= 3.3.1)