diff --git a/Gemfile b/Gemfile
index e0db00a..318d094 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,7 +7,7 @@ end
 
 gem 'bootstrap-sass', '3.4.1'
 gem 'rails', '~> 5.1.4'
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'
 gem 'coffee-rails', '~> 4.2'
diff --git a/Gemfile.lock b/Gemfile.lock
index 049f936..6f181fb 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -136,7 +136,8 @@ GEM
       railties (>= 3.0.0)
     pg (0.21.0)
     public_suffix (4.0.1)
-    puma (3.12.4)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -271,7 +272,7 @@ DEPENDENCIES
   momentjs-rails
   parsley-rails
   pg (~> 0.20)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.1.4)
   rails-controller-testing
   rspec (~> 3.7)