diff --git a/restful_resource.gemspec b/restful_resource.gemspec
index 392d77a..61b1bbe 100644
--- a/restful_resource.gemspec
+++ b/restful_resource.gemspec
@@ -33,6 +33,6 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'faraday-http-cache', '~> 2.2'
   spec.add_dependency 'faraday_middleware', '~> 1.0'
   spec.add_dependency 'link_header'
-  spec.add_dependency 'rack', '~> 2.2'
+  spec.add_dependency 'rack', '>= 2.2', '< 4.0'
   spec.add_dependency 'typhoeus', '~> 1.4'
 end