diff --git a/History.markdown b/History.markdown
index 90e3a9fd..214f098b 100644
--- a/History.markdown
+++ b/History.markdown
@@ -13,6 +13,7 @@
   * Add debug output to theme rendering (#5195)
   * fix minitest deprecation warning in test (#6839)
   * Memoize `Site#site_data` (#6809)
+  * Memoize document output extension (#6814)
 
 ### Minor Enhancements