It will be open source, end to end encrypted using Signal’s double ratchet encryption protocol, and he plans to make it easy for fediverse platforms to integrate it. The beta will release later this month.
He’s also the creator of https://fedidb.org btw
I wonder, what 'works with the fediverse ’ could mean for a messenger and what could be features not already implemented by different messengers, like elements or the very signal.