diff --git a/Gemfile b/Gemfile
index 0bf7000..14fe490 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'carrierwave',             '1.2.2' #image uploader
 gem 'mini_magick',             '4.9.4' #image resizing
 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 5af4bd4..33e4509 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -297,7 +297,8 @@ 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)
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -420,7 +421,7 @@ DEPENDENCIES
   minitest (= 5.10.3)
   minitest-reporters (= 1.1.14)
   pg (= 0.18.4)
-  puma (= 3.12.6)
+  puma (= 4.3.12)
   rails (= 5.1.6)
   rails-controller-testing (= 1.0.2)
   sass-rails (= 5.0.6)