diff --git a/Gemfile b/Gemfile
index 3d2645f..8dd83f8 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ ruby File.read('.ruby-version').strip
 gem 'rails', '~> 5.2.0'
 gem 'pg',    '>= 0.18', '< 2.0'
 gem 'redis', '~> 4.0'
-gem 'puma',  '~> 3.11'
+gem 'puma',  '~> 4.3'
 gem 'sidekiq'
 gem 'clockwork'
 gem 'exception_notification'
diff --git a/Gemfile.lock b/Gemfile.lock
index 18b2ee5..836f5b5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -171,7 +171,9 @@ 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 (5.12.2)
@@ -194,7 +196,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (4.0.1)
-    puma (3.12.1)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-livereload (0.3.17)
       rack
@@ -344,7 +347,7 @@ DEPENDENCIES
   kaminari
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rack-livereload
   rails (~> 5.2.0)
   rails-assets-normalize-scss (= 3.0.3)!