diff --git a/Gemfile b/Gemfile
index e903850..dbbbf6a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '~> 5.1.5'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # 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 6a05bfc..087aa97 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -140,7 +140,8 @@ GEM
     nokogiri (1.8.2)
       mini_portile2 (~> 2.3.0)
     public_suffix (3.0.2)
-    puma (3.11.3)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.0.4)
     rack-contrib (2.0.1)
       rack (~> 2.0)
@@ -229,7 +230,7 @@ DEPENDENCIES
   launchy (= 2.4.3)
   listen (>= 3.0.5, < 3.2)
   meta_request (= 0.5.0)
-  puma (~> 3.7)
+  puma (~> 4.3)
   rack-cors (= 1.0.2)
   rails (~> 5.1.5)
   shoulda (= 2.11.3)