This message occurs if a minicalendar token contains zap string (:z or :Z or :ZL or :ZP, followed by ~ or =) immediately followed by the letter f, indicating a 1/8 and 2/9 combined dates minicalendar modifier, but which is not followed by one of the only 2 allowed options; namely 18 and 29.

Topic 188945, last updated on 22-Mar-2026