I don’t think there’s likely to ever be a meaningful version 2 of the AP spec. There’s no mechanism to negotiate it, and no institutional support to collect the implementers and do the work. The best I can imagine is a separate protocol that exists as a successor to activitypub.
That said, what would I want in such a successor?
- Remove ld/rdf as a federation format. It’s awful at that. Use something with real schemas that support code generation. RDF can be supported as a query format, if desired.
- A protocol-defined federated authentication mechanism.
- Absolutely no self-authenticating messages. In fact, no forwardable messages of any kind. It’s an unbelievable security risk, and it’s really distressing to me that I have to keep explaining that.
- Specifications for how to reply to an object, how to comment on it, how to locate replies and comments, how to approve and reject those replies and comments. Specifications to determine who has authorization to reply/comment/accept/reject, and how to convey that authorization to third parties. Specifications to convey error information.
- A real extension mechanism. LD/RDF handwaved that without actually solving anything. I hope it would be obvious that this is necessary with that aspect of the spec removed.
- Specifications for managing distributed ownership of shared resources. Particularly groups, but I expect more uses would flourish if it wasn’t so nearly impossible to do at all.
- Distinguish between persistent messages and ephemeral ones like presence and status updates.
I’m sure I could go on, but this seems like plenty for what seems like a theoretical exercise.