diff --git a/Gemfile b/Gemfile
index a3f4ae1..24416b6 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.4', '>= 5.2.4.3'
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # 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 92479d9..3a68b66 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -157,7 +157,8 @@ GEM
     pg (1.2.3)
     popper_js (1.16.0)
     public_suffix (4.0.6)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -273,7 +274,7 @@ DEPENDENCIES
   omniauth
   omniauth-google-oauth2
   pg (>= 0.18, < 2.0)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.4, >= 5.2.4.3)
   sass-rails (~> 5.0)
   selenium-webdriver