diff --git a/Gemfile b/Gemfile
index 8f05ea6..4948b1e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,7 +7,7 @@ gem 'mini_magick',             '4.7.0'
 gem 'will_paginate',           '3.1.6'
 gem 'bootstrap-will_paginate', '1.0.0'
 gem 'bootstrap',               '~> 4.3.1'
-gem 'puma',                    '~> 3.9.1'
+gem 'puma',                    '~> 4.3.12'
 gem 'uglifier',                '>= 3.2.0'
 gem 'coffee-rails',            '~> 4.2.2'
 gem 'jquery-rails',            '~> 4.3.1'
diff --git a/Gemfile.lock b/Gemfile.lock
index 7566646..ae2a0f9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -169,7 +169,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.0.3)
-    puma (3.9.1)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -301,7 +302,7 @@ DEPENDENCIES
   minitest (= 5.10.3)
   minitest-reporters (= 1.1.14)
   mysql2 (~> 0.4.4)
-  puma (~> 3.9.1)
+  puma (~> 4.3.12)
   rails (~> 5.2)
   rails-controller-testing (= 1.0.2)
   rspec-rails (~> 3.8)