diff --git a/Gemfile b/Gemfile
index 850680d..f5988e7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -25,4 +25,5 @@ end
 group :test do
   gem 'faraday', '~>2.0'
   gem 'faraday-retry', '~>2.0'
+  gem 'rackup', '~> 2.1'
 end
diff --git a/spec/support/ssl_server.rb b/spec/support/ssl_server.rb
index e532298..b8bbed8 100644
--- a/spec/support/ssl_server.rb
+++ b/spec/support/ssl_server.rb
@@ -32,7 +32,7 @@ def webrick_opts port
   require "webrick"
   require "webrick/https"
   require "rack"
-  require "rack/handler/webrick"
+  require "rackup/handler/webrick"
 
   opts = webrick_opts(4444)