Cardano has activated the van Rossem hard fork, upgrading the mainnet to protocol version 11 on Saturday. The update is expected to lower smart contract execution costs and set the stage for Ouroboros Leios, a major scalability upgrade for the protocol.
On-chain records from Cardanoscan show the network moved from Protocol Version 10 in epoch 643 to Version 11 in epoch 644. According to a weekly development report from Input Output, the upgrade includes Plutus improvements and enhancements to the Plutus cost model, and it lays the groundwork for the next scheduled upgrade — the Dijkstra era hard fork, which will introduce Ouroboros Leios.
Ouroboros Leios is a proposed scaling solution for Cardano’s Ouroboros proof-of-stake consensus, targeted for late 2026. Its aim is to significantly raise transactions per second while preserving the security guarantees of Ouroboros.
The van Rossem upgrade is also notable as Cardano’s first governance-driven hard fork; previous protocol upgrades were coordinated directly by Input Output, the engineering firm behind Cardano’s development.
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