diff --git a/Gemfile b/Gemfile
index 09a67556..85d73f4a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,7 +9,7 @@ gem 'rails', '~> 5.2'
 # Use postgres as database
 gem 'pg'
 # Use Puma as the app server
-gem 'puma'
+gem 'puma', '>= 4.3.12'
 # For Travis CI
 gem 'rake', group: :test
 # Make loading large Ruby/Rails apps faster