diff --git a/Gemfile b/Gemfile
index a6cfe07..6721fe8 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,7 @@ source "https://rubygems.org"
 
 git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
 
-gem "sinatra", "2.0.1"
+gem "sinatra", "4.0.0"
 gem "puma", "4.2.1" 
 gem 'puma-metrics'