diff --git a/Gemfile b/Gemfile
index e73d9a7..dbddae2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.4', '>= 5.2.4.1'
 # 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 a11b840..a57ba14 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -96,7 +96,9 @@ 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 (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.14.0)
@@ -106,7 +108,8 @@ GEM
       mini_portile2 (~> 2.4.0)
     pg (1.2.2)
     public_suffix (4.0.3)
-    puma (3.12.2)
+    puma (4.3.11)
+      nio4r (~> 2.0)
     rack (2.1.1)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -216,7 +219,7 @@ DEPENDENCIES
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.4, >= 5.2.4.1)
   rspec-rails (~> 3.4, >= 3.4.2)
   sass-rails (~> 5.0)