I just received this from Xara re: the special upgrade price that was set to expire today.

Because our support staff were overwhelmed by a huge last minute rush to
upgrade, the Xtreme upgrade offer for Xara X1 owners has been extended
for one more week. The last day for upgrading at the launch price of
just $29/$39 (plus shipping and VAT where appropriate) will now be
Wednesday 7th December...but please don't leave it to the last minute!

Visit http://www.xara.com/products/xtreme/upgrade.asp for further
information on upgrading Xara X1 to Xtreme.
Gary