diff --git a/Gemfile b/Gemfile
index db953bc..1dd4141 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'dotenv-rails', groups: [:development, :test]
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+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 6634971..b821b6e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -135,7 +135,8 @@ GEM
     orm_adapter (0.5.0)
     pg (1.2.3)
     public_suffix (4.0.5)
-    puma (3.12.6)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -241,7 +242,7 @@ DEPENDENCIES
   kaminari
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   sass-rails (~> 5.0)
   selenium-webdriver