diff --git a/Gemfile.lock b/Gemfile.lock
index 967cbdb..3f69099 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -84,7 +84,7 @@ DEPENDENCIES
   simplecov (~> 0.21)
   simplecov-lcov (~> 0.8)
   test-unit (~> 3.0)
-  yard (~> 0.0, >= 0.9.20)
+  yard (~> 0.0, >= 0.9.36)
 
 BUNDLED WITH
    2.3.4
diff --git a/rubytree.gemspec b/rubytree.gemspec
index 52dd4c3..46c6e1a 100644
--- a/rubytree.gemspec
+++ b/rubytree.gemspec
@@ -77,7 +77,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'simplecov', '~> 0.21'
   s.add_development_dependency 'simplecov-lcov', '~> 0.8'
   s.add_development_dependency 'test-unit', '~> 3.0'
-  s.add_development_dependency 'yard', '~> 0.0', '>= 0.9.20'
+  s.add_development_dependency 'yard', '~> 0.0', '>= 0.9.36'
 
   s.post_install_message = <<-END_MESSAGE
     ========================================================================