diff --git a/Gemfile b/Gemfile
index bb7de7e..efbea92 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 # Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker
 gem 'webpacker'
 
diff --git a/Gemfile.lock b/Gemfile.lock
index fd11c63..5c132ec 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -98,7 +98,9 @@ GEM
     marcel (0.3.3)
       mimemagic (~> 0.3.2)
     method_source (0.9.2)
-    mimemagic (0.3.2)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.1)
     mini_portile2 (2.4.0)
     minitest (5.11.3)
@@ -107,7 +109,8 @@ GEM
     nokogiri (1.10.7)
       mini_portile2 (~> 2.4.0)
     public_suffix (3.0.3)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-cors (1.0.2)
     rack-proxy (0.6.5)
@@ -215,7 +218,7 @@ DEPENDENCIES
   factory_bot_rails
   faker
   listen (>= 3.0.5, < 3.2)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rack-cors
   rails (~> 5.2.1)
   rails-controller-testing