diff --git a/Gemfile b/Gemfile
index 8f3c17e..09013d3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.1'
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index 2c31ba4..fd6eb53 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -259,7 +259,9 @@ GEM
       actionpack (>= 3.2.0, < 6.1)
     method_source (1.0.0)
     mime-types (2.99.3)
-    mimemagic (0.3.5)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_magick (4.11.0)
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
@@ -290,7 +292,8 @@ GEM
       actionmailer (>= 3)
       premailer (~> 1.7, >= 1.7.9)
     public_suffix (4.0.6)
-    puma (3.12.0)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     pundit (1.1.0)
       activesupport (>= 3.0.0)
     rack (2.2.3)
@@ -410,7 +413,7 @@ DEPENDENCIES
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.1)
   sass-rails (~> 5.0)
   spring