diff --git a/Gemfile b/Gemfile
index 9abe5ed..3456c58 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ ruby '2.4.0'
 
 gem 'rails', '~> 5.0.2'
 gem 'pg', '~> 0.21' 
-gem 'puma', '~> 3.11'
+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 734178d..4c37d84 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -153,7 +153,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.0.2)
-    puma (3.11.3)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.0.4)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -285,7 +286,7 @@ DEPENDENCIES
   pg (~> 0.21)
   popper
   pry
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.0.2)
   rails_layout
   redis (~> 3.0)