diff --git a/Gemfile b/Gemfile
index 19960b6..6ecb4cd 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.3'
 # Use mysql as the database for Active Record
 gem 'mysql2', '>= 0.4.4', '< 0.6.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
 # gem 'jbuilder', '~> 2.5'
 # Use Redis adapter to run Action Cable in production
diff --git a/Gemfile.lock b/Gemfile.lock
index e5b50f1..56fc542 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -80,7 +80,8 @@ GEM
     nio4r (2.4.0)
     nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
-    puma (3.12.2)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.8)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -141,7 +142,7 @@ DEPENDENCIES
   dotenv-rails
   listen (>= 3.0.5, < 3.2)
   mysql2 (>= 0.4.4, < 0.6.0)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   spring
   spring-watcher-listen (~> 2.0.0)