diff --git a/Gemfile b/Gemfile
index 6ae4b9e..2e2bd8a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.3'
 # Use postgres as the database for Active Record
 gem 'pg'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+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 dbbf7fe..35d2691 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -123,7 +123,8 @@ GEM
       pry (~> 0.9)
       slop (~> 3.0)
     public_suffix (3.1.0)
-    puma (3.12.1)
+    puma (4.3.11)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -246,7 +247,7 @@ DEPENDENCIES
   pry-nav
   pry-rails
   pry-remote
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   rails-controller-testing
   rspec-core