diff --git a/railsapp/Gemfile b/railsapp/Gemfile
index 4338239..9cb5efe 100644
--- a/railsapp/Gemfile
+++ b/railsapp/Gemfile
@@ -10,7 +10,7 @@ gem 'rails', '~> 5.1.6'
 # Use mysql as the database for Active Record
 gem 'mysql2', '>= 0.3.18', '< 0.6.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/railsapp/Gemfile.lock b/railsapp/Gemfile.lock
index 27bb3f4..eac5ce2 100644
--- a/railsapp/Gemfile.lock
+++ b/railsapp/Gemfile.lock
@@ -133,7 +133,8 @@ GEM
       activerecord (>= 4.2, < 5.3)
       request_store (~> 1.1)
     public_suffix (4.0.3)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -244,7 +245,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mysql2 (>= 0.3.18, < 0.6.0)
   paper_trail (~> 9.1.1)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.1.6)
   sass-rails (~> 5.0)
   selenium-webdriver