diff --git a/Gemfile b/Gemfile
index 3c60dfd..2659129 100644
--- a/Gemfile
+++ b/Gemfile
@@ -17,7 +17,7 @@ gem 'bcrypt', '~> 3.1.7'
 gem 'will_paginate', '3.1.5'
 gem 'bootstrap-will_paginate', '1.0.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3', '>= 4.3.9'
 # Use SCSS for stylesheets
 gem 'bootstrap-sass', '~> 3.3.7'
 gem 'jquery-rails'
diff --git a/Gemfile.lock b/Gemfile.lock
index 3fa755c..9a04bd2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -108,7 +108,8 @@ GEM
       mini_portile2 (~> 2.5.0)
       racc (~> 1.4)
     public_suffix (4.0.6)
-    puma (3.12.6)
+    puma (4.3.10)
+      nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)
     rack-test (1.1.0)
@@ -220,7 +221,7 @@ DEPENDENCIES
   jquery-rails
   listen (>= 3.0.5, < 3.2)
   minitest-reporters
-  puma (~> 3.7)
+  puma (~> 4.3, >= 4.3.9)
   rails (~> 5.1.6)
   rails-controller-testing
   sass-rails (~> 5.0)