Some reviews of the Karma explain it can act as a digital music receiver on an ethernet network.

They're wrong. It can't. It was on the wishlist (although never public, so I don't know why people think it can), but didn't make the cut for the first release. Hopefully, it'll be added in a future release, but I can't say for sure.

Does anyone know if this is a Software feature coming to the EMPEG in v.3?

It won't be coming to the empeg for v3, because it doesn't exist yet.