diff --git a/Gemfile b/Gemfile
index 36b421c..32dfb09 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,7 +5,7 @@ gem 'jbuilder', '~> 2.5'
 gem 'jquery-rails'
 gem 'jquery_mask_rails', '~> 0.1.0'
 gem 'nokogiri', '~> 1.8.1'
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 4.3'
 gem 'rails', '~> 5.0.0', '>= 5.0.0.1'
 gem 'rubocop', require: false
 gem 'sass-rails', '~> 5.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index e20dc37..fbd29f4 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -104,7 +104,8 @@ GEM
     pg (1.0.0)
     powerpack (0.1.2)
     public_suffix (3.0.2)
-    puma (3.11.4)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.5)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -227,7 +228,7 @@ DEPENDENCIES
   listen (~> 3.0.5)
   nokogiri (~> 1.8.1)
   pg
-  puma (~> 3.0)
+  puma (~> 4.3)
   rails (~> 5.0.0, >= 5.0.0.1)
   rspec-rails
   rubocop