diff --git a/Gemfile b/Gemfile
index 73805f88..3c8a2d0d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -20,7 +20,7 @@ end
 group :development do
   gem 'json_spec', '~> 1.1', '>= 1.1.5'
 
-  gem 'mdl', '~> 0.11.0'
+  gem 'mdl', '~> 0.13.0'
 
   gem 'mocha', '~> 2.7'