diff --git a/omniauth-microsoft_graph.gemspec b/omniauth-microsoft_graph.gemspec
index cad4774..2fd6103 100644
--- a/omniauth-microsoft_graph.gemspec
+++ b/omniauth-microsoft_graph.gemspec
@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency 'jwt', '~> 2.0'
   spec.add_runtime_dependency 'omniauth', '~> 2.0'
   spec.add_runtime_dependency 'omniauth-oauth2', '~> 1.8.0'
-  spec.add_development_dependency "sinatra", '~> 2.2'
+  spec.add_development_dependency "sinatra", '~> 4.1'
   spec.add_development_dependency "rake", '~> 12.3.3', '>= 12.3.3'
   spec.add_development_dependency 'rspec', '~> 3.6'
   spec.add_development_dependency "mocha", '~> 0'