pyCluster 1.0.16 introduces the version 2 private PY protocol for authenticated pyCluster peers. It adds structured capability and limit negotiation, session-specific handshakes, bounded decentralized topology exchange with alternate-route failover, liveness probes and RTT, clean route withdrawals, convergence and asymmetry diagnostics, and conservative public topology reporting. PC protocol operation remains the fallback during rolling upgrades.\n\nThe release also corrects live peer-family promotion, cluster-role labels, stale public peer presentation, QRZ placeholder stability, and several System Operator presentation details.\n\nValidation: 645 tests passed; 48 network-dependent tests were intentionally deselected. The release was staged on pycluster.ai3i.net and passed all configured telnet, System Operator web, and public web readiness checks.