Singapore Airlines KrisFlyer - How often do SQ Menu change?

I was wondering how often the menu changes? I was checking the menus for my flights, and the menus for my flights are a few years old (SIA 15/16). I am not sure how often the menus change, if it doesn't change very often, or that my flight doesn't get much traffic from FTers.

I have checked here
http://www.flyertalk.com/forum/singapore-airlines-krisflyer/443989-y-menu.html
http://www.flyertalk.com/forum/trip-reports/833998-all-airline-ft-menu-collection.html