diff --git a/Gemfile b/Gemfile
index 9817c14..473a9cc 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ gem 'bootstrap', '~> 4.1.2'
 gem 'jquery-rails'
 gem 'kaminari'
 # 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 d61ec25..306c9d8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -125,7 +125,9 @@ GEM
     marcel (0.3.2)
       mimemagic (~> 0.3.2)
     method_source (0.9.0)
-    mimemagic (0.3.2)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.0)
     mini_portile2 (2.3.0)
     minitest (5.11.3)
@@ -138,7 +140,8 @@ GEM
     orm_adapter (0.5.0)
     popper_js (1.14.3)
     public_suffix (3.0.2)
-    puma (3.12.0)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.5)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -240,7 +243,7 @@ DEPENDENCIES
   kaminari
   listen (>= 3.0.5, < 3.2)
   mysql2 (>= 0.4.4, < 0.6.0)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.0)
   sass-rails (~> 5.0)
   selenium-webdriver