diff --git a/Gemfile b/Gemfile
index 1688cbe..e955186 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,7 +10,7 @@ gem 'nokogiri', '1.13.4'
 gem 'will_paginate',           '3.1.6'
 gem 'bootstrap-will_paginate', '1.0.0'
 gem 'bootstrap-sass', '3.4.1'
-gem 'puma',         '3.12.6'
+gem 'puma',         '4.3.12'
 gem 'sass-rails',   '5.0.6'
 gem 'uglifier',     '3.2.0'
 gem 'coffee-rails', '4.2.2'
diff --git a/Gemfile.lock b/Gemfile.lock
index 3859bef..fee30ce 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -321,7 +321,8 @@ GEM
     pry (0.11.3)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     racc (1.6.0)
     rack (2.2.3)
     rack-test (0.8.2)
@@ -472,7 +473,7 @@ DEPENDENCIES
   nicescroll-rails (~> 3.5, >= 3.5.4.1)
   nokogiri (= 1.13.4)
   pg (= 0.18.4)
-  puma (= 3.12.6)
+  puma (= 4.3.12)
   rails (= 5.1.4)
   rails-controller-testing (= 1.0.2)
   rubocop