Pinnacle boss difficulty levels and item drop chance.

So it seems there's only three difficulty levels for Pinnacle bosses now but every Wikipedia page States 4 due to outdated info? Is it still 4? The atlas tree doesn't say anything about boss difficulty on the individual nodes anymore for the boss trees like breach or expedition.

Previously you would have to do a level 4 difficulty to get megalomaniac diamond to drop. What difficulty level do you need to do now?