diff --git a/Gemfile b/Gemfile
index 2bed1d5..9dbcf74 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,7 +9,7 @@ ruby '2.5.1'
 
 gem 'rails', '~> 5.0.1'
 gem 'pg', '~> 0.18'
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'
 gem 'jquery-rails'
diff --git a/Gemfile.lock b/Gemfile.lock
index 246c284..dd45512 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -96,7 +96,8 @@ GEM
       mini_portile2 (~> 2.4.0)
     pg (0.21.0)
     public_suffix (3.0.3)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -209,7 +210,7 @@ DEPENDENCIES
   jquery-rails
   listen (~> 3.0.5)
   pg (~> 0.18)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.0.1)
   redis
   rspec-rails (~> 3.5)