diff --git a/Gemfile b/Gemfile
index 65133dd..ba5fe4e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.3'
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # 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'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
diff --git a/Gemfile.lock b/Gemfile.lock
index 290c691..0ea0384 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -71,7 +71,9 @@ 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 (5.11.3)
@@ -85,7 +87,8 @@ GEM
       method_source (~> 0.9.0)
     pry-rails (0.3.9)
       pry (>= 0.10.4)
-    puma (3.12.6)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-proxy (0.6.5)
       rack
@@ -159,7 +162,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
   pry-rails
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   redis (~> 4.0)
   spring