...must come to an end. And even some not so good things, to think about it.
Anyway, what's coming to an end? Easy - support for old software, of course! In this case, the old software is Windows XP Embedded with Service Pack 1, also called XPE SP1. When is also easy - April 10, 2007 (that's Patch Tuesday in April, for those of you keeping score at home). What this means is that the April Embedded Security Update Rollup CD will be the last one to contain any SP1 specific updates.
Full details can be found on the Embedded Team Blog, as well as the Mobile and Embedded Communications Extranet (also called the ECE). Details on MS Lifecycle Policy can be found on, oddly enough, this Microsoft web page.