Cardano has activated the van Rossem hard fork, moving its mainnet to Protocol Version 11 after the upgrade took effect at the epoch boundary on July 18.
Summary
- Cardano activated Protocol Version 11 after governance approval moved the van Rossem hard fork forward.
- The upgrade improves Plutus costs while preparing Cardano for Ouroboros Leios and higher future throughput.
- Van Rossem is Cardano’s first hard fork ratified through onchain governance, marking a governance milestone.
Intersect confirmed that the hard fork had been successfully enacted after weeks of testing, infrastructure updates, and governance voting.
The upgrade follows its ratification on July 13 by Cardano’s delegated representatives, stake pool operators, and Constitutional Committee. The Cardanoscan governance record shows that the proposal called for Protocol Version 11. Intersect reported 77.63% DRep support and 52.7% SPO support when the required thresholds were met.
Van Rossem is an intra-era hard fork, so Cardano remains within the Conway era while updating parts of its protocol. The upgrade introduces new Plutus capabilities and cost model changes designed to make some smart contract operations cheaper. It also includes technical updates aimed at improving Plutus performance and other parts of the network.
The mainnet activation followed earlier testing on the Preview and Preprod networks. Preview moved to Protocol Version 11 in May, while the Preprod upgrade followed in June after developers addressed tooling compatibility issues. As previously reported by crypto.news, the mainnet proposal arrived in June after those testing and preparation stages.
Dijkstra and Ouroboros Leios come next
The van Rossem hard fork also prepares Cardano for its next planned protocol upgrade. Input Output said, “As well as Plutus improvements and Plutus Cost Model enhancements, this upgrade lays the foundation for the next upgrade, the Dijkstra era hard fork, which will introduce Ouroboros Leios to Cardano.”
Leios is a proposed upgrade to Cardano’s Ouroboros proof-of-stake system that aims to raise transaction throughput while keeping its existing security model. Development remains underway. According to the latest Cardano weekly report, the consensus team has continued stabilizing the Leios testnet, released two new prototype builds, and worked on changes intended to improve block certification rates. Crypto.news previously reported that Leios forms part of Cardano’s wider protocol development roadmap.
Onchain governance takes control of the upgrade process
Van Rossem also marks the first Cardano hard fork to move through the network’s Voltaire onchain governance system rather than relying on the earlier coordination model led by founding development groups. Cardano said the final decision to ratify and execute the upgrade rested with DReps, SPOs, and the Constitutional Committee after technical teams completed the required preparation.
The process follows Cardano’s broader move toward community-led decisions. The same system has also produced different outcomes for funding proposals. As crypto.news reported earlier, the community rejected a 7.8 million ADA request for the 2026 Cardano Summit, leading to its cancellation. Meanwhile, other treasury funding has supported protocol work that includes Leios, Hydra, and Mithril.
With van Rossem now active, Cardano is operating on Protocol Version 11 while development continues on Dijkstra and Ouroboros Leios. The network has not announced a final mainnet launch date for Leios, although recent ecosystem coverage has placed the planned scaling upgrade later in 2026.
