diff --git a/Gemfile b/Gemfile
index 7c06982..8f57e89 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,7 +9,7 @@ gem 'rails', '~> 5.2'
 # Use postgresql as the database for Active Record
 gem 'pg', '~> 1'
 # 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/Gemfile.lock b/Gemfile.lock
index 76dcfd5..b78c0a9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -177,7 +177,9 @@ GEM
     marcel (0.3.3)
       mimemagic (~> 0.3.2)
     method_source (0.9.2)
-    mimemagic (0.3.5)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.5.0)
     minitest (5.14.4)
@@ -221,7 +223,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (4.0.6)
-    puma (3.12.6)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)
     rack-livereload (0.3.17)
@@ -403,7 +406,7 @@ DEPENDENCIES
   omniauth-github (~> 2)
   omniauth-rails_csrf_protection
   pg (~> 1)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rack-livereload (~> 0.3.16)
   rails (~> 5.2)
   rails-assets-clipboard!