diff --git a/Ruby/progate/rails5_study_10/tweet_app/Gemfile b/Ruby/progate/rails5_study_10/tweet_app/Gemfile
index 2645ea27..4dac5834 100644
--- a/Ruby/progate/rails5_study_10/tweet_app/Gemfile
+++ b/Ruby/progate/rails5_study_10/tweet_app/Gemfile
@@ -2,7 +2,7 @@ source 'https://rubygems.org'
 
 gem 'rails', '5.0.3'
 # Use Puma as the app server
-gem 'puma', '3.6.2'
+gem 'puma', '3.12.6'
 # Use SCSS for stylesheets
 gem 'sass-rails', '5.0.6'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Ruby/progate/rails5_study_10/tweet_app/Gemfile.lock b/Ruby/progate/rails5_study_10/tweet_app/Gemfile.lock
index 3b31dc85..5f8341bb 100644
--- a/Ruby/progate/rails5_study_10/tweet_app/Gemfile.lock
+++ b/Ruby/progate/rails5_study_10/tweet_app/Gemfile.lock
@@ -79,7 +79,7 @@ GEM
       slop (~> 3.4)
     pry-rails (0.3.4)
       pry (>= 0.9.10)
-    puma (3.6.2)
+    puma (3.12.6)
     racc (1.5.2)
     rack (2.2.3)
     rack-test (0.6.3)
@@ -160,7 +160,7 @@ DEPENDENCIES
   jquery-rails (= 4.2.2)
   listen (= 3.0.8)
   pry-rails (= 0.3.4)
-  puma (= 3.6.2)
+  puma (= 3.12.6)
   rails (= 5.0.3)
   sass-rails (= 5.0.6)
   spring (= 2.0.1)