What constitutes HP cannon?

[milztoday]

No: HPFGUIDX 39226

Hi everyone. I haven't posted in the group for a long, long time. 
Anyhow, way back when the group membership hovered in the triple 
digits, we were hashing out what constituted HP cannon. IIRC, we 
agreed that the novels by Rowling and the Rowling interviews are 
cannon. I don't think we ever decided if the movie was "cannon" 
because, although it had Rowling's approval, the movie might take 
certain creative liberties.

So what is the official HP for GrownUps policy statement regarding 
cannon?

Milz