diff --git a/Gemfile b/Gemfile
index 05cadbc..f50ed5e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '~> 5.1.7'
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+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 b436d9a..64a1566 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -91,7 +91,8 @@ GEM
     nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
     pg (1.1.4)
-    puma (3.12.1)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.0.8)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -151,7 +152,7 @@ DEPENDENCIES
   byebug
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.1.7)
   spring
   spring-watcher-listen (~> 2.0.0)