Well that really is a no brainer, considering that A) avast 7 beta at least is likely to come out early next year and B) XP is still supported until April 2014. So I would say that given avasts previous history of support for older OSes with even win2k currently supported that XP will be supported in avast7.

Since avast7 will also be looking at working with windows8, there may well be features that will work with windows8 which may not be supported in winXP (or possibly other later versions).

So lets not start any rumours about avast7 not supporting XP.