Hi! http://ctan.org/pkg/ifxetex claims that the version of ifxetex distributed by texlive is 0.5 and the copyright is from 2006-2008. When one clicks on the 'Package documentation' link, the PDF that one gets says it's version 0.6 and has a date of 2010/09/12. This looks like the tlpobj file needs updating :) Cheers, Thomas