Yes, I understand that. None of that addresses what we were discussing.
What I'm getting at is, I'm pretty sure there is no mechanism on the chargers or the batteries that physically prevents one from putting a new Lithium-Ion/XCP/whatever they call it into an older non-multi-chemistry charger.
The keys I show on the attached picture are also present on the Ni-Cad batteries.
The XCP batteries do not have a female key-way. Any keying system that would prevent you from installing a Lithium-Ion battery in an incompatible charger would have to be present on the incompatible charger, not the battery, otherwise, the battery wouldn't be able to be used in a tool without a key-way.
Ultimately, getting back to my original point in the thread:
Be careful you don't put your new battery in the old charger, because there's nothing physically preventing you from doing so.