I'm unable to download the errata from the Wizard's site currently, so I don't have the exact text before me. But from what I've gathered, there is a change that untyped bonuses that come from the same "source" no longer stack. Source is not precisely defined, they instead give the examples of source in parenthesis (class feature, power, etc.) or something to that effect.
So if Power X gives a +2 untyped bonus to attack rolls and Power Y gives a +2 untyped bonus to attack rolls do they still stack? They are both powers, but they are different powers.
A small nerf interpretation would be that since the sources are different attack powers they stack.
A big nerf interpretation would be the source of the +2 comes from attack powers, therefore they don't stack.
So if Power X gives a +2 untyped bonus to attack rolls and Power Y gives a +2 untyped bonus to attack rolls do they still stack? They are both powers, but they are different powers.
A small nerf interpretation would be that since the sources are different attack powers they stack.
A big nerf interpretation would be the source of the +2 comes from attack powers, therefore they don't stack.