Cardano activated its van Rossem hard fork on July 18, 2026, completing the network’s first protocol upgrade whose final approval and execution were determined entirely through its decentralized onchain governance system.
The upgrade took effect at 21:44:51 UTC at the boundary of epoch 644, corresponding to Cardano slot 192,844,800. It moved the blockchain to Protocol Version 11 while keeping it within the existing Conway ledger era, making van Rossem an “intra-era” hard fork rather than a broader transition to a new ledger architecture.
Unlike earlier Cardano upgrades that depended more heavily on the network’s founding entities or temporary governance arrangements, van Rossem required formal approval from all three bodies established under Cardano’s post-Chang governance framework: delegated representatives, or DReps; stake pool operators; and the Constitutional Committee.
The hard-fork action was ratified on July 13 after receiving 77.63% support from DReps, above the required 60% threshold. Stake pool operator support reached 52.7%, narrowly clearing the 51% requirement, while six Constitutional Committee members voted that the action was constitutional. Five committee approvals were required, and one member did not vote.
Onchain Vote Completes Governance Transition
The activation provides an important operational test for Cardano’s governance model, which was introduced progressively through the Chang and Plomin upgrades. Those earlier changes created the mechanisms through which ADA holders can delegate voting power, stake pool operators can participate in protocol decisions and the Constitutional Committee can assess whether governance actions comply with the network’s constitution.
Van Rossem demonstrated that those institutions can collectively authorize a technically significant network change without relying on an offchain decision by a central development company.
The process still required extensive coordination. Intersect, Cardano’s member-based ecosystem organization, convened a Hard Fork Working Group involving Input Output, the Cardano Foundation, EMURGO, Midnight, infrastructure providers and other contributors. However, the group coordinated testing and readiness rather than possessing unilateral authority to activate the upgrade.
Testing took place across the SanchoNet, Preview and Preprod environments. Preview moved to Protocol Version 11 on May 8, while Preprod completed its upgrade on June 10 after developers addressed compatibility issues affecting infrastructure tools including Ogmios and Kupo.
Protocol Version 11 Expands Plutus Capabilities
Van Rossem introduces targeted improvements to Cardano’s Plutus smart-contract platform, ledger consistency and node security without changing transaction structure.
The upgrade makes a broader set of built-in functions available across Plutus V1, V2 and V3, reducing differences between script generations. It also adds more efficient case expressions for basic types and introduces native capabilities including arrays, optimized multi-asset value operations, modular exponentiation and improved list manipulation.
Additional changes include cryptographic improvements involving BLS12-381 operations and stronger uniqueness protections for stake pool verification keys. A related Plutus cost-model update was approved separately and enacted on June 18, allowing pricing parameters for the new functions to be available when the hard fork went live.
For developers, the intra-era structure lowers the integration burden compared with major transitions such as Chang because applications do not need to adopt a new transaction format. For Cardano, however, the larger significance is institutional: protocol evolution has moved from community consultation to binding, executable onchain control.
