diff --git a/Gemfile b/Gemfile
index b9a6e47..2aff0de 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.3'
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # 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 5c590ea..9e02186 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -142,7 +142,8 @@ GEM
       method_source (~> 0.9.0)
     pry-rails (0.3.9)
       pry (>= 0.10.4)
-    puma (3.12.2)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     pusher-client (0.6.2)
       json
       websocket (~> 1.0)
@@ -285,7 +286,7 @@ DEPENDENCIES
   pg (>= 0.18, < 2.0)
   pry (>= 0.12.2)
   pry-rails (>= 0.3.9)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   rest-client (>= 2.1.0)
   rspec-rails (>= 2.3.1)