diff --git a/Gemfile b/Gemfile
index c58bf5f..d60085b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.4', '>= 5.2.4.2'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # 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 09ab57e..fea0272 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -121,7 +121,9 @@ GEM
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2020.0425)
-    mimemagic (0.3.4)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.14.0)
@@ -137,7 +139,8 @@ GEM
       mimemagic (~> 0.3.0)
       terrapin (~> 0.6.0)
     public_suffix (4.0.4)
-    puma (3.12.4)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -256,7 +259,7 @@ DEPENDENCIES
   jquery-rails
   listen (>= 3.0.5, < 3.2)
   paperclip (~> 6.1)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.4, >= 5.2.4.2)
   sass-rails (~> 5.0)
   sassc-rails (>= 2.1.0)