diff --git a/Gemfile b/Gemfile
index 8462f39..9f0f90f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'mysql2'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Puma webserver
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 4.3'
 # Use Uglifier as compressor for JavaScript assets
 gem 'uglifier', '>= 1.3.0'
 # Use CoffeeScript for .coffee assets and views
diff --git a/Gemfile.lock b/Gemfile.lock
index 1d1f092..f6206ba 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -114,7 +114,9 @@ GEM
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2020.0512)
-    mimemagic (0.3.5)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.14.1)
@@ -131,7 +133,8 @@ GEM
       mime-types
       mimemagic (~> 0.3.0)
       terrapin (~> 0.6.0)
-    puma (3.12.6)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -234,7 +237,7 @@ DEPENDENCIES
   jquery-rails
   mysql2
   paperclip
-  puma (~> 3.0)
+  puma (~> 4.3)
   rails (= 5.0.7.2)
   sass-rails (~> 5.0)
   sdoc (~> 0.4.0)