diff --git a/Gemfile b/Gemfile
index 4c02888..5bc794d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '~> 5.2.3'
 # Set a minimum version for Rack to avoid security vulnerability in Rack <2.0.6
 gem 'rack', '>= 2.0.6'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+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 1bbb524..c775e27 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -136,7 +136,9 @@ GEM
     marcel (0.3.3)
       mimemagic (~> 0.3.2)
     method_source (0.9.2)
-    mimemagic (0.3.3)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.1)
     mini_portile2 (2.4.0)
     minitest (5.11.3)
@@ -163,7 +165,8 @@ GEM
     pry-rails (0.3.6)
       pry (>= 0.10.4)
     public_suffix (3.0.0)
-    puma (3.10.0)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     pundit (2.0.1)
       activesupport (>= 3.0.0)
     rack (2.0.7)
@@ -351,7 +354,7 @@ DEPENDENCIES
   pg (~> 0.21.0)
   pry-byebug (~> 3.4.0)
   pry-rails
-  puma (~> 3.7)
+  puma (~> 4.3)
   pundit
   rack (>= 2.0.6)
   rails (~> 5.2.3)