How does the Code of Practice for Safety of Large Commercial Sailing and Motor Vessels relate to the term LY1, LY2 and LY3?

LY1 is the abbreviated term used to refer to the original Large Commercial Yacht Code which came into effect in December 1998. LY2 is the abbreviated term for the revised Code, which came into effect in September 2004. LY3 is the abbreviated term for the revised Code, which came (or comes, depending on the time of the web-site update) into effect in August 2013.