diff --git a/Gemfile b/Gemfile
index acf6be1..8c660d5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -20,7 +20,7 @@ gem "rspec-rails"
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.1.7'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+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 0731eea..d77b28b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -127,7 +127,8 @@ GEM
       rack (>= 1.2, < 3)
     popper_js (1.16.0)
     public_suffix (4.0.3)
-    puma (3.12.2)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.1.1)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -250,7 +251,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mini_racer
   oauth2
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.1.7)
   rest-client
   rspec-rails