@LemmyDev@nx yep - a shame. Without ActivityPub client-to-server being wide-spread, it doesn't make sense to implement it as a transport protocol for Delta Chat next to SMTP/IMAP.
@nx it's conceptually similar but API/protocol-wise quite different. If someone would try to implement another transport layer in our Rust Core library then a big part of the apps would "just work". But that is a big if, and not a trivial undertaking.
@nx@LemmyDev I asked around in a dev chat - whether it's possible depends a lot on whether ActivityPub offers additional fields for metadata. In E-Mail you can just add more headers, not sure how easy that is with ActivityPub. Maybe the @LemmyDev folks know it out of their head?