diff --git a/spec/dummy-app/Gemfile b/spec/dummy-app/Gemfile
index 392654a..d8ebc68 100644
--- a/spec/dummy-app/Gemfile
+++ b/spec/dummy-app/Gemfile
@@ -6,7 +6,7 @@ ruby '2.6.3'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.2.3'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
diff --git a/spec/dummy-app/Gemfile.lock b/spec/dummy-app/Gemfile.lock
index 69f1169..35f4ac6 100644
--- a/spec/dummy-app/Gemfile.lock
+++ b/spec/dummy-app/Gemfile.lock
@@ -80,7 +80,8 @@ GEM
     nio4r (2.3.1)
     nokogiri (1.10.3)
       mini_portile2 (~> 2.4.0)
-    puma (3.12.1)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -160,7 +161,7 @@ DEPENDENCIES
   byebug
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   rollbar
   sass-rails (~> 5.0)