As jayne said 6th edition is Saturday, so we'll have to wait and see what happens.
6th rules seem to point to a few changes to how power weapons work in the new edition, along with how vehicles are damaged.
Tau are also rumoured to be updated sometime in 2013 but that is purely speculation since the rumour blackout, no one i really 100% sure what is coming far down the line.
We will likely get a new tau FAQ after 6th edition comes out.
Hope that helps.