README.md in dce_lti-0.5.1 vs README.md in dce_lti-0.5.2

@@ -95,9 +95,18 @@
       lti.consumer_key = ->(launch_params) {
         Consumer.find_by(context_id: launch_params[:context_id]).consumer_key
       }
     }
 
+### p3p headers
+
+On IE11, any security setting "Low" or greater rejects all third party cookies
+without p3p headers.
+
+DceLti includes the [p3p](https://rubygems.org/gems/p3p) middleware by default
+to insert a basic p3p header for you automatically.  You can configure this
+with an initializer, see the p3p docs for examples.
+
 ### Customizing the Tool Provider XML configuration
 
 The tool config instance (provided by
 [IMS::LTI::ToolConfig](https://github.com/instructure/ims-lti/blob/master/lib/ims/lti/tool_config.rb))
 can be configured directly via the `tool_config_extensions` lambda. This allows