diff --git a/lib/rb/thrift.gemspec b/lib/rb/thrift.gemspec
index 8e8deba..166a93f 100644
--- a/lib/rb/thrift.gemspec
+++ b/lib/rb/thrift.gemspec
@@ -27,11 +27,11 @@
 
   s.require_paths = %w[lib ext]
 
-  s.add_development_dependency 'rspec', '~> 2.10.0'
-  s.add_development_dependency "rack", "~> 1.5.2"
-  s.add_development_dependency "rack-test", "~> 0.6.2"
-  s.add_development_dependency "thin", "~> 1.5.0"
-  s.add_development_dependency "bundler"
-  s.add_development_dependency 'rake', '~> 10.5.0'
+  s.add_development_dependency 'rspec', ['>= 2.10.0', '< 2.14.0']
+  s.add_development_dependency "rack", "~> 1.5"
+  s.add_development_dependency "rack-test", "~> 0.6"
+  s.add_development_dependency "thin", "~> 1.5"
+  s.add_development_dependency "bundler", "~> 1"
+  s.add_development_dependency 'rake', '~> 10.5'
 end