diff --git a/ruby/rails/container/Application/Gemfile b/ruby/rails/container/Application/Gemfile
index 13ab5125..aebd6270 100644
--- a/ruby/rails/container/Application/Gemfile
+++ b/ruby/rails/container/Application/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '~> 5.1.4'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 5.6'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/ruby/rails/container/Application/Gemfile.lock b/ruby/rails/container/Application/Gemfile.lock
index 6db7c143..a9e4d207 100644
--- a/ruby/rails/container/Application/Gemfile.lock
+++ b/ruby/rails/container/Application/Gemfile.lock
@@ -89,7 +89,8 @@ GEM
     nokogiri (1.8.5)
       mini_portile2 (~> 2.3.0)
     public_suffix (3.0.2)
-    puma (3.11.0)
+    puma (5.6.7)
+      nio4r (~> 2.0)
     rack (2.0.4)
     rack-test (0.8.2)
       rack (>= 1.0, < 3)
@@ -178,7 +179,7 @@ DEPENDENCIES
   coffee-rails (~> 4.2)
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
-  puma (~> 3.7)
+  puma (~> 5.6)
   rails (~> 5.1.4)
   sass-rails (~> 5.0)
   selenium-webdriver