diff --git a/h5bp/directive-only/ssl.conf b/h5bp/directive-only/ssl.conf
index 21d10e6..40a6a21 100644
--- a/h5bp/directive-only/ssl.conf
+++ b/h5bp/directive-only/ssl.conf
@@ -34,7 +34,7 @@ keepalive_timeout 300s; # up from 75 secs default
 # This header tells browsers to cache the certificate for a year and to connect exclusively via HTTPS.
 #add_header Strict-Transport-Security "max-age=31536000;";
 # This version tells browsers to treat all subdomains the same as this site and to load exclusively over HTTPS
-#add_header Strict-Transport-Security "max-age=31536000; includeSubdomains;";
+#add_header Strict-Transport-Security "max-age=31536000; includeSubDomains;";
 
 # This default SSL certificate will be served whenever the client lacks support for SNI (Server Name Indication).
 # Make it a symlink to the most important certificate you have, so that users of IE 8 and below on WinXP can see your main site without SSL errors.