- Do I need to have a current version of "Moomoo Milk" outside my deck if I'm playing the older versions of the card in Modified Format?
- Technically speaking the "Heart Gold/Soul Silver" version is a different card and it does not do the same thing as the older versions used to (it removes more damage counters now). So you cannot play "Moo-Moo Milk" from "Neo Genesis" nor "Expedition" in the current 2009-2010 Modified Format.
Source:
PUI Rules Team (2010-02-18)