Each link will contain the legacy catalog for a specified catalog version and date. During the installation, it will create a new catalog with the Date listed behind the catalog name. You will need to open the Catalog Manager and Activate/Deactive catalogs as needed. It is very important that you only have one catalog active to ensure that you are receiving the correct prices.
October 10
2009
September 09
March 092008
January 08May 08
June 08September 08
2007
September 07February 07
2006
October 06