Protocol Versioning

Protocols evolve. Payload schemas add fields. Priority tiers get recalibrated. Channel subscriptions change. Without versioning, a protocol change that works for the sender breaks the recipient — and the failure is silent until someone notices degraded output.

Every message envelope includes a protocol version field. Version negotiation is simple: the sender specifies the version it is using. If the recipient supports that version, it processes normally. If it supports a newer version, it processes with backward compatibility. If it only supports an older version, it returns a version-mismatch error. The orchestrator maintains a compatibility matrix — which agents support which protocol versions — and routes messages through translation layers when necessary. We are currently on protocol v2.3. The migration from v1 to v2 added the TTL field and priority tiers. The v2.3 patch added confidence scores to intelligence payloads.