[XSLT 2.0] Conformance levels

I am somewhat peeved and the restrictions on a processor claiming
basic level conformance - specifically not being allowed to assign
type annotation to attributes other than xdt:untypedAtomic.

This means, that having developed a processor to basic level
conformance, you cannot then develop it further towards full
schema-aware conformance, except in one fell swoop, as if you
implement on a step-by-step basis, you promptly lose the ability to
claim basic level conformance.
-- 
Colin Paul Adams
Preston Lancashire