diff --git a/site/_docs/windows.md b/site/_docs/windows.md
index b87140b9..81e909c9 100644
--- a/site/_docs/windows.md
+++ b/site/_docs/windows.md
@@ -39,6 +39,5 @@ built-in support for UNIX systems, it requires an extra gem for compatibility
 with Windows. Add the following to the Gemfile for your site:
 
 {% highlight ruby %}
-require 'rbconfig'
-gem 'wdm', '~> 0.1.0' if RbConfig::CONFIG['target_os'] =~ /mswin|mingw/i
+gem 'wdm', '~> 0.1.0' if Gem.win_platform?
 {% endhighlight %}