diff --git a/Gemfile b/Gemfile
index 95c7f26..338e621 100644
--- a/Gemfile
+++ b/Gemfile
@@ -18,7 +18,7 @@ gem 'turbolinks', '~> 5'
 gem 'puma', '~> 3.11'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'
-gem 'sinatra', :require => nil # for sidekiq UI
+gem 'sinatra', '>= 4.0.0', :require => nil # for sidekiq UI
 gem 'sidekiq-status'
 gem 'sidekiq'
 gem 'redis-rails'