@upofadown Schemes based on RFC 9580 are going to be quite interoperable.I'm aware of at least 7 serious independent codebases that implement RFC 9580, and almost as many mature implementations of draft-ietf-openpgp-pqc.Adding autocrypt2 to the mix is a very small additional layer on top of these already widely available building blocks.(And sure, GnuPG is doing its own thing. But that is really not very relevant to Delta Chat or its users.)