diff --git a/rack-server_status.gemspec b/rack-server_status.gemspec
index 8f941f8..0963b67 100644
--- a/rack-server_status.gemspec
+++ b/rack-server_status.gemspec
@@ -23,7 +23,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
 
   spec.add_dependency "worker_scoreboard"
-  spec.add_development_dependency "bundler", "~> 1.7"
+  spec.add_development_dependency "bundler", "~> 2.2"
   spec.add_development_dependency "rake", "~> 13.0"
   spec.add_development_dependency "rspec"