Cardano Governance Becomes Mainnet Code With van Rossem Hard Fork

Cardano will activate the van Rossem hard fork on July 18, 2026, at approximately 21:45 UTC, converting a ratified governance action into active mainnet rules. The network will move to Protocol Version 11 following approval by delegated representatives, stake pool operators and the Constitutional Committee.

Van Rossem is an intra-era hard fork, meaning Cardano will remain within the Conway era rather than transition to a new ledger era. ADA holders will not need to migrate funds or take any action, while exchanges, stake pools, wallets and other infrastructure providers must operate software compatible with Protocol Version 11.

Cardano’s On-Chain Vote Becomes an Active Protocol Upgrade

Van Rossem is the first Cardano hard fork to complete the full governance process introduced during the network’s transition to decentralized on-chain decision-making.

Previous protocol upgrades were primarily coordinated by Cardano’s founding organizations and their technical teams. Protocol Version 11 was instead submitted as an on-chain governance action and required approval from Cardano’s three active governance bodies: DReps, stake pool operators and the Constitutional Committee.

Intersect coordinated the technical preparation through its Hard Fork Working Group, ecosystem readiness monitoring and the governance action process. Final authorization, however, was determined by votes recorded directly on the Cardano network.

The significance extends beyond the individual technical changes. Cardano’s governance system has now demonstrated that it can authorize a protocol-level upgrade without a founding organization making the final decision. On-chain governance is therefore moving from a constitutional framework into an operational mechanism for maintaining and changing the network itself.

Once the new epoch begins, the approved governance action will no longer exist only as a proposal recorded on-chain. Its parameters and technical changes will become part of the rules enforced by Cardano mainnet nodes.

The upgrade was named after Max van Rossem, a Cardano community contributor involved in governance, constitutional work and ecosystem development. The name previously received community support through a separate governance information action.

Protocol Version 11 Expands Plutus Functionality

The largest technical component of the van Rossem upgrade concerns Plutus, Cardano’s smart contract execution environment.

Protocol Version 11 makes the complete supported set of Plutus built-in functions available across Plutus V1, V2 and V3. Older script versions previously lacked access to some functionality introduced in later Plutus releases, which could require developers to migrate or recompile contracts before using newer primitives.

The upgrade also introduces native case expressions for Bool, Integer and Data types. These additions allow scripts to process different data structures more directly, reducing the amount of logic required for operations that previously depended on multiple checks.

Other additions include a native Array type for more efficient indexing, an optimized MaryEraValue representation for operations involving Cardano native assets and faster list processing through dropList.

Van Rossem also adds cryptographic capabilities including modular exponentiation and BLS12-381 multi-scalar multiplication. These functions can support more advanced cryptographic applications, including systems that use zero-knowledge proofs.

The new primitives can reduce execution costs when developers redesign scripts to use them. Existing decentralized applications will not automatically become cheaper after the hard fork, as the impact depends on whether individual projects implement the available optimizations.

Protocol Version 11 additionally introduces ledger-level verification of unique stake pool VRF keys, adjusts reference input rules for Plutus V1 and V2 scripts and moves certain Constitutional Committee voting restrictions into formal ledger validation.

For Cardano developers, the immediate change is a broader and more consistent set of tools available at the protocol level. DeFi applications, wallets, infrastructure providers and cryptographic projects can begin integrating those capabilities after activation without waiting for another major ledger-era transition.

Network Readiness Clears the Path to Activation

Readiness data published before ratification showed that more than 93% of blocks were already being produced by nodes compatible with Protocol Version 11. Exchange readiness represented approximately 84% of tracked market liquidity.

The high proportion of upgraded block-producing nodes reduces the risk of disruption during the transition. Exchanges, wallets, indexers, stake pools and other infrastructure providers must still complete their own updates to continue following the Protocol Version 11 ledger rules correctly.

ADA and Cardano native assets will remain available throughout the transition. The hard fork does not require users to move tokens, adopt a new address format or change how assets are held in Cardano wallets.

Van Rossem also completes part of the technical preparation for Cardano’s future Dijkstra era, which is expected to include further protocol changes connected to Ouroboros Leios and higher network throughput.

At the start of the new epoch on July 18, Cardano’s governance architecture will produce its first fully authorized hard fork outcome. The practical result will be visible at protocol level: upgraded nodes will enforce the new rules, developers will gain access to the expanded Plutus capabilities and the network’s future hard forks will have an established on-chain path from proposal to mainnet activation.