diff --git a/doc/plugins/calendar.mdwn b/doc/plugins/calendar.mdwn
index fb3cfb130..5aa20a211 100644
--- a/doc/plugins/calendar.mdwn
+++ b/doc/plugins/calendar.mdwn
@@ -19,7 +19,9 @@ pages from templates (overriding the existing ones).
 * `calendar_fill_gaps` - If set (and `calendar_autocreate` is set as well),
   build calendar pages of emty years and months (but does not build pages older
   than the older page, and younger than the younger page of the pagespec). If
-  not, thoses empty calendar pages will be skipped.
+  not, thoses empty calendar pages will be skipped. *Note:* The archive pages
+  will not be automatically updated if this option changes. It is up to the
+  user to delete relevant pages, and rebulid the wiki.
 
 ## CSS