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
SimpleX looks intriguing
It’s great, I’m migrating all my contacts to it. AGPL, no phone number or identifier, decentralized, official lemmy community, fast development pace, …