diff --git a/discussions/module04/todo_app/Gemfile b/discussions/module04/todo_app/Gemfile
index 80be782..d4d184c 100644
--- a/discussions/module04/todo_app/Gemfile
+++ b/discussions/module04/todo_app/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 6.0.3', '>= 6.0.3.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3', '~> 1.4'
 # Use Puma as the app server
-gem 'puma', '~> 4.1'
+gem 'puma', '~> 5.6'
 # Use SCSS for stylesheets
 gem 'sass-rails', '>= 6'
 # Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker
diff --git a/discussions/module04/todo_app/Gemfile.lock b/discussions/module04/todo_app/Gemfile.lock
index fb644cf..12ead9e 100644
--- a/discussions/module04/todo_app/Gemfile.lock
+++ b/discussions/module04/todo_app/Gemfile.lock
@@ -93,16 +93,18 @@ GEM
     marcel (0.3.3)
       mimemagic (~> 0.3.2)
     method_source (1.0.0)
-    mimemagic (0.3.5)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.14.1)
     msgpack (1.3.3)
-    nio4r (2.5.2)
+    nio4r (2.7.0)
     nokogiri (1.10.9)
       mini_portile2 (~> 2.4.0)
     public_suffix (4.0.5)
-    puma (4.3.5)
+    puma (5.6.8)
       nio4r (~> 2.0)
     rack (2.2.2)
     rack-proxy (0.6.5)
@@ -203,7 +205,7 @@ DEPENDENCIES
   capybara (>= 2.15)
   jbuilder (~> 2.7)
   listen (~> 3.2)
-  puma (~> 4.1)
+  puma (~> 5.6)
   rails (~> 6.0.3, >= 6.0.3.1)
   sass-rails (>= 6)
   selenium-webdriver