diff --git a/DOCUMENTATION.md b/DOCUMENTATION.md
index 957c0e81..5eb6d208 100644
--- a/DOCUMENTATION.md
+++ b/DOCUMENTATION.md
@@ -2324,7 +2324,7 @@ Supported placeholders (data used from VCARD)
  * `{nickname}`: nick name (RFC6350#6.2.3)
 
 Supported extra placeholders
- * `{age}`: age, toggles to creation of single events instead using RRULE
+ * `{age}`: age, toggles to creation of single events instead using RRULE (only active if year + age_max >= current year)
 
 Fallback is supported if placeholders inside `[...|...]` (first successful resolved one is used)