Cardano activates the van Rossem hard fork: the first governance-driven upgrade in history

Cardano’s mainnet has officially launched the van Rossem hard fork, upgrading the protocol version from 10 to 11. This is the first hard fork in Cardano’s history driven by community governance, not only lowering smart contract execution costs, but also laying the groundwork for the Ouroboros Leios expansion solution slated to go live later this year.
(Background: Adaverse proposal | Vasil hard fork upgrade schedule in question—Is a Cardano ecosystem singularity coming?)
(Background details: Cardano has completed the Alonzo upgrade, officially entering the DeFi era—smart contract functionality is live!)

Table of Contents

Toggle

• Not just lower prices: Plutus improvements and cost model updates
• First in history: a hard fork driven by community governance
• Ouroboros Leios: a large-scale expansion plan before year-end
• From van Rossem to Dijkstra: Cardano’s upgrade roadmap

Cardano’s mainnet formally launched the van Rossem hard fork on Saturday, upgrading the protocol version from 10 to 11, bringing infrastructure for lower smart contract costs and subsequent expansion upgrades to the network.

According to on-chain data shown by Cardanoscan, the network remained at Protocol Version 10 at the end of epoch 643, and officially switched to Version 11 after entering epoch 644.

Not just lower prices: Plutus improvements and cost model updates

This upgrade includes performance improvements to the Plutus smart contract platform, as well as enhancements to the Plutus cost model. In its weekly development report, Input Output noted that these updates lay the technical groundwork for the next-stage Dijkstra-era hard fork.

For developers, the Plutus cost model updates mean that smart contract gas fees will more accurately reflect actual computation costs, helping reduce the fee burden of everyday transactions.

First in history: a hard fork driven by community governance

Unlike previous upgrades coordinated by Input Output engineers, the van Rossem upgrade is the first hard fork in Cardano’s history driven by community governance. This marks further maturation of Cardano’s decentralized governance mechanisms.

In past hard forks (such as Vasil, Alonzo, Chang), Input Output unified coordination and deployment on the developer side. van Rossem, however, determines the timing and parameters of the upgrade through Cardano’s governance proposal process, with ADA holders voting.

Ouroboros Leios: a large-scale expansion plan before year-end

Ouroboros Leios is an expansion proposal for the Ouroboros proof-of-stake consensus mechanism used by Cardano, scheduled to launch by the end of 2026. Its core goal is to dramatically increase transactions per second (TPS) without weakening security guarantees.

Input Output stated in its report: “In addition to Plutus improvements and Plutus cost model enhancements, this upgrade paves the way for the next-stage Dijkstra-era hard fork, which will bring Ouroboros Leios into Cardano.”

If the Leios expansion plan is delivered as scheduled, Cardano’s theoretical throughput could rise from today’s tens of transactions per second to several hundred, or even over a thousand, narrowing the scalability gap with competitors such as Ethereum and Solana.

From van Rossem to Dijkstra: Cardano’s upgrade roadmap

The van Rossem hard fork is just the first step in Cardano’s 2H 2026 upgrade roadmap. According to IO’s development roadmap, the Dijkstra-era hard fork follows immediately after, and is expected to bring:

• Ouroboros Leios正式上線，實現鏈上擴充套件
• 智慧合約執行成本的進一步降低
• 治理機制的持續驗證與完善

For ADA holders, the successful launch of van Rossem is not only a technical milestone, but also validates that Cardano’s community governance system can effectively coordinate network-level upgrades.