@ISOWYEAR — returns the ISO 8601 week-numbering year (1601 through 9999) for the specified date, i.e. the year in which the closest Thursday falls. The date may be in any input date format supported by this plugin; it must be a valid date within the supported range.

Syntax:
%@ISOWYEAR[date,infmt]

datethe date to examine; if omitted, uses today’s date
infmtthe input date format, used to interpret ambiguous dates

• Note: This function does not exist in 4NT / Take Command v10 and earlier.