diff --git a/Gemfile b/Gemfile
index e33a5f4..a95e090 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,7 +5,7 @@ ruby '2.3.5'
 gem 'rails', '~> 5.1.6'
 
 # infrastructure
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 5.6'
 gem 'sqlite3', group: [:development, :test]
 gem 'pg', group: :production
 gem 'sidekiq', group: :production
diff --git a/Gemfile.lock b/Gemfile.lock
index c42dc8d..218ba7b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -90,7 +90,8 @@ GEM
     nokogiri (1.10.2)
       mini_portile2 (~> 2.4.0)
     pg (1.1.4)
-    puma (3.12.1)
+    puma (5.6.4)
+      nio4r (~> 2.0)
     rack (2.0.6)
     rack-protection (2.0.5)
       rack
@@ -219,7 +220,7 @@ DEPENDENCIES
   listen (~> 3.0.5)
   nokogiri (~> 1)
   pg
-  puma (~> 3.0)
+  puma (~> 5.6)
   rails (~> 5.1.6)
   rails-controller-testing
   rails_real_favicon