Poison Vs Titanic Monsters

Does anyone know how poison now works against titanic monsters?
I have a game soon against Tyranids and he will be bringing a Bio-titan, another friend also has a Scabbithax LOW for Nurgle that i will be facing at some point.
I know it used to wound on 6's instead of 4's does anyone know if this is still the case in 8th as i can't seem to find it anywhere, i shouldn't think they have changed it though.

Check the Poisoned Weapons rule in the Codex. Now wound on 6+ with poison against Titanic.

The +2 bonus on on stuff like ossifiers does only exclude vehicles.
So they would wound Titanic's on4+.