diff --git a/Gemfile b/Gemfile
index 4cf1701..429ea57 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.2'
 gem 'bootstrap-sass', '3.4.1'
 gem 'jquery-rails'
 # 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 b4c0f9b..680d0b9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -126,7 +126,8 @@ GEM
     pry (0.13.0)
       coderay (~> 1.1)
       method_source (~> 1.0)
-    puma (3.12.4)
+    puma (4.3.11)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -226,7 +227,7 @@ DEPENDENCIES
   minitest (= 5.14.0)
   minitest-reporters (= 1.1.14)
   pg (= 0.20.0)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.2)
   rails-controller-testing (= 1.0.2)
   sass-rails (~> 5.0)