diff --git a/Gemfile b/Gemfile
index cf5415e..c60a7ad 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '~> 5.0.2'
 # Use postgresql as the database for Active Record
 gem 'pg', '~> 0.18'
 # Use Puma as the app server
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 4.3', '>= 4.3.8'
 # Use Figaro as the environment variables manager
 gem 'figaro'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder