Sage previously announced that as of December 31, 2012, they will no longer support updates, including the Tax Table Update (TTU), to version 4.3.
However, due to the new 2013 Medicare requirements, Sage will provide Medicare changes for 2013 in January and 941 updates in March 2013, so you can comply with the 2013-Q1 filing requirements. This will be particularly important to you, as TTUs will no longer be provided for this version.