diff --git a/Gemfile b/Gemfile
index 38fb38e..4bf84ba 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,7 +10,7 @@ gem 'rails', '~> 5.0.2'
 # Use postgresql as the database for Active Record
 gem 'pg', '0.20.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.0'
+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 723e3ec..6a27d3f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -124,7 +124,8 @@ GEM
     pg (0.20.0)
     powerpack (0.1.1)
     public_suffix (2.0.5)
-    puma (3.8.2)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.3)
     rack-cors (0.4.1)
     rack-test (0.6.3)
@@ -233,7 +234,7 @@ DEPENDENCIES
   lograge
   mini_magick
   pg (= 0.20.0)
-  puma (~> 3.0)
+  puma (~> 4.3)
   rack-cors
   rails (~> 5.0.2)
   rspec-activemodel-mocks