diff --git a/server/Gemfile b/server/Gemfile
index 1087b38..5086a32 100644
--- a/server/Gemfile
+++ b/server/Gemfile
@@ -6,7 +6,7 @@ gem 'rails', '5.1.4'
 # Use postgresql as the database for Active Record
 gem 'pg', '~> 0.21'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/server/Gemfile.lock b/server/Gemfile.lock
index d576313..ba1721d 100644
--- a/server/Gemfile.lock
+++ b/server/Gemfile.lock
@@ -204,7 +204,8 @@ GEM
     pry-rails (0.3.6)
       pry (>= 0.10.4)
     public_suffix (3.0.2)
-    puma (3.11.2)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.8)
     rack-test (0.8.3)
       rack (>= 1.0, < 3)
@@ -388,7 +389,7 @@ DEPENDENCIES
   newrelic_rpm
   pg (~> 0.21)
   pry-rails
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (= 5.1.4)
   rails-erd
   rails-i18n