diff --git a/Gemfile b/Gemfile
index 3830dcc..65b1ba1 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '~> 5.0.1'
 # Use postgresql as the database for Active Record
 gem 'pg', '~> 0.18'
 # Use Puma as the app server
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index bb50c0a..9556d80 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -140,7 +140,8 @@ GEM
     pry-rails (0.3.9)
       pry (>= 0.10.4)
     public_suffix (3.1.1)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)
     rack-protection (2.1.0)
@@ -246,7 +247,7 @@ DEPENDENCIES
   newrelic_rpm
   pg (~> 0.18)
   pry-rails
-  puma (~> 3.0)
+  puma (~> 4.3)
   rack (>= 2.0.8)
   rails (~> 5.0.1)
   rails_12factor