diff --git a/Gemfile b/Gemfile
index 88cd383..1996c45 100644
--- a/Gemfile
+++ b/Gemfile
@@ -18,7 +18,7 @@ gemspec
 gem 'rake', '~> 12.0'
 
 group :documentation do
-  gem 'yard', '~> 0.0'
+  gem 'yard', '~> 0.9.11'
 end
 
 group :test do