diff --git a/Gemfile b/Gemfile
index 66dae85..a9de538 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'mysql2'
 gem 'composite_primary_keys', '~> 11'
 
 # Use Puma as the app server
-gem 'puma', '~> 3.12.6'
+gem 'puma', '~> 4.3.12'
 # 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 08daf08..55e9fe2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -145,7 +145,9 @@ GEM
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2019.1009)
-    mimemagic (0.3.3)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.14.1)
@@ -156,7 +158,8 @@ GEM
     nokogiri (1.10.9)
       mini_portile2 (~> 2.4.0)
     public_suffix (4.0.3)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     pundit (1.1.0)
       activesupport (>= 3.0.0)
     rack (2.2.3)
@@ -260,7 +263,7 @@ DEPENDENCIES
   kaminari
   listen (~> 3.0.5)
   mysql2
-  puma (~> 3.12.6)
+  puma (~> 4.3.12)
   pundit (~> 1.1.0)
   rails (~> 5.2.3)
   sass-rails (~> 5.0)