Problem
The spec has no versioning mechanism for events or the sync protocol. As the system evolves, peers running different versions need to interoperate or gracefully degrade.
Options to explore
-
Version field in CreateServer — the genesis event declares the protocol version. All events in that server's DAG conform to that version.
-
ALPN-style protocol negotiation — at the sync layer, peers negotiate protocol version before exchanging events. Iroh already uses ALPN for protocol routing.
-
Event kind versioning via serde — use #[serde(default)] and optional fields for backward-compatible evolution. New event kinds are ignored by old peers (unknown variants).
-
Epoch events — a special event that declares "from this point forward, use protocol version N." Requires admin vote.
References
Problem
The spec has no versioning mechanism for events or the sync protocol. As the system evolves, peers running different versions need to interoperate or gracefully degrade.
Options to explore
Version field in CreateServer — the genesis event declares the protocol version. All events in that server's DAG conform to that version.
ALPN-style protocol negotiation — at the sync layer, peers negotiate protocol version before exchanging events. Iroh already uses ALPN for protocol routing.
Event kind versioning via serde — use
#[serde(default)]and optional fields for backward-compatible evolution. New event kinds are ignored by old peers (unknown variants).Epoch events — a special event that declares "from this point forward, use protocol version N." Requires admin vote.
References
docs/specs/2026-04-01-per-author-merkle-dag-state-design.md(Appendix A)