diff --git a/Gemfile b/Gemfile
index 114c04e..9b4bf71 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,7 +3,7 @@ source 'http://rubygems.org'
 ruby '2.7.7'
  
 gem 'tilt', '~> 1.4.1'
-gem "sinatra"
+gem "sinatra", ">= 4.1.0"
 gem "rack-flash3"
 gem "haml"
 gem "slim"