"Though users at the Audio Fakes Discord and the DeepFaceLab Discord are intensely interested in combining the two technologies into a single video+voice live deepfake architecture, no such product has publicly emerged as yet."
I am not aware of what was used in that occasion; there is also a good chance that the scammers could hack a system internally - the stake is stellar.
Surely, to convince the other part during a phone call a high degree of capability for interaction is required; from the same article, right above your quote:
> we can reasonably assume that the speaker is using a live, real-time deepfake framework
The quoted article is from late 2021. In these current days, we are seeing denounces according to which
> Voice scams are on the rise in a dramatic way. They were the second most common con trick in America last year, and they’re headed for the top spot this year (ex Voice scams: a great reason to be fearful of AI at https://news.ycombinator.com/item?id=35459261 )