diff --git a/Gemfile b/Gemfile
index 35a16ad..804454a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,7 +3,7 @@ git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
 gem 'rails', '~> 5.2.2'
 gem 'mysql2'
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 gem 'devise'
 gem 'haml'
 gem 'sucker_punch', '~> 2.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index 78884dc..34ae343 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -127,7 +127,8 @@ GEM
       method_source (~> 0.9.0)
     pry-rails (0.3.9)
       pry (>= 0.10.4)
-    puma (3.12.6)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -249,7 +250,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mysql2
   pry-rails (~> 0.3.6)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2.2)
   rubocop (~> 0.63.0)
   sass-rails (~> 5.0)