The XPocalypse is almost upon us: Tomorrow, April 8, is the last time Microsoft will issue security updates for the 13-year-old Windows XP. This months Patch Tuesday will have a total of four security updates, Microsoft says, which will also include the final updates for Microsoft Office 2003 and a patch for Microsoft Office for Mac 2011. Two of the four updates are rated critical, which is Microsofts highest security threat rating.