diff --git a/Gemfile b/Gemfile
index 851954b..832237c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.4'
 # Use mysql as the database for Active Record
 gem 'mysql2', '>= 0.4.4', '< 0.6.0'
 # 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 0c924e2..cbf2769 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -174,7 +174,9 @@ GEM
     materialize-sass (1.0.0)
       autoprefixer-rails (>= 6.0.3)
     method_source (1.0.0)
-    mimemagic (0.3.5)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.14.1)
@@ -197,7 +199,8 @@ GEM
     pry-rails (0.3.9)
       pry (>= 0.10.4)
     public_suffix (4.0.5)
-    puma (3.12.6)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -340,7 +343,7 @@ DEPENDENCIES
   materialize-sass (~> 1.0.0)
   mysql2 (>= 0.4.4, < 0.6.0)
   pry-rails
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.4)
   rubocop
   sass-rails (~> 5.0)