Overview
- The Van Rossem hard fork moved Cardano mainnet to Protocol Version 11 when it activated at the epoch boundary on July 18, 2026, after weeks of testing on Preview and Preprod networks.
- The upgrade was ratified entirely through onchain governance with DReps, stake pool operators, and the Constitutional Committee signing off and node-readiness exceeding the constitutional 85% threshold before activation.
- Protocol Version 11 bundles five Cardano Improvement Proposals that add new Plutus built-ins and types — including modular exponentiation, array types, multi-scalar multiplication and a native Value type — and unifies built-ins across Plutus V1–V3.
- Ledger rules tighten stake-pool identity and cryptographic checks to reduce attack vectors, while cost-model changes lower many smart-contract execution costs but require developers to rebuild or update contracts to realize savings.
- Markets have shown a muted price response so far and the community now shifts to delivering the follow-on Dijkstra/Ouroboros Leios scaling work later in 2026, which will test whether the governance process can reliably steer future protocol upgrades.