Sieve notify support.?

I've looked through the docs and specifically the supported standards  
and I can't find a answer to the following question.

How much of Sieve Notify is implemented in 6.2 and 6.3?

I know there's some support in there but, I can't remember if it's  
6.2 or 6.3 or how much is implemented in each version.

Thanks!
-Chris