Cardano activated the Van Rossem hard fork on July 18, 2026 at 21:44:51 UTC, upgrading the network from Protocol Version 10 to 11. The upgrade marks the first protocol change in Cardano's eight-year history approved entirely through on-chain governance rather than top-down coordination by foundin...
"A hard fork is one of the most visible and celebrated moments in Cardano development, but rarely is it the work of a single team or a single decision." — Ian Hartwell, Intersect MBO
Cardano activated the Van Rossem hard fork on July 18, 2026 at 21:44:51 UTC, upgrading the network from Protocol Version 10 to 11. The upgrade marks the first protocol change in Cardano's eight-year history approved entirely through on-chain governance rather than top-down coordination by founding entity Input Output. Delegated representatives (DReps) voted 78.97% in favor, stake pool operators (SPOs) cleared with 53.02% support, and the Constitutional Committee approved 7-0 with zero dissent. Approximately 93% of block-producing nodes had already adopted the new version before activation.
The fork bundles five Cardano Improvement Proposals focused on cryptographic primitives, data structures, and script execution cost reduction. These are preparatory changes for Ouroboros Leios, a parallelized consensus upgrade currently running on the Musashi Dojo public testnet since June 23, 2026, which targets 30–65x throughput increases over current capacity.
The governance process itself is the more consequential development. Ten months after the Chang hard fork introduced Cardano's Voltaire-era governance framework in September 2024, the system processed and enacted its first protocol-level upgrade without intervention from Input Output, the Cardano Foundation, or Emurgo as decision-makers. Whether this model scales to more contentious decisions remains an open question — a 7.8 million ADA treasury proposal for the Cardano Summit 2026 failed by 1.46 percentage points in June, resulting in the event's cancellation.
Van Rossem packages five Cardano Improvement Proposals into a single protocol version increment. The upgrade was preceded by two governance actions: a Plutus Cost Model parameter update (enacted June 18, 2026) and the hard fork initiation action itself.
CIP-133: Multi-Scalar Multiplication over BLS12-381. Adds native multi-scalar multiplication on the BLS12-381 elliptic curve, enabling batch verification of multiple signatures in a single operation. Prior to this change, teams building zero-knowledge proofs, multi-signature wallets, and compliance tooling relied on off-chain computation for these operations. On-chain verification reduces trust assumptions and lowers per-signature gas costs.
CIP-138: Native Array Type. Introduces a native array data structure to the Plutus scripting language. Prior Plutus versions required developers to simulate arrays using linked lists, which added computational overhead. The native implementation reduces memory consumption and execution costs for contracts that handle ordered collections.
CIP-153: Multi-Asset Value Optimization. Improves how the ledger handles multi-asset token bundles, reducing serialization costs for transactions involving multiple native tokens.
Plutus Cost Model Enhancements. Two additional CIPs adjust cost parameters for existing Plutus primitives and establish cost settings for the new primitives introduced by CIP-133 and CIP-138. The combined effect reduces script execution costs across the board.
The upgrade activated at the epoch 643-to-644 boundary with zero reported downtime. The preview testnet had forked on May 8 and the preprod testnet on June 10, providing approximately five weeks of pre-production testing.
Cardano's CIP-1694 governance framework, activated by the Chang hard fork in September 2024, distributes decision-making across three bodies:
| Body | Voting Basis | Van Rossem Result | Threshold | |------|-------------|-------------------|-----------| | Delegated Representatives (DReps) | Stake-weighted (1 lovelace = 1 vote) | 78.97% in favor | 60% required | | Stake Pool Operators (SPOs) | Stake-weighted | 53.02% in favor | 51% required | | Constitutional Committee (CC) | One member, one vote | 7/7 constitutional | Simple majority |
Hard fork actions require approval from all three bodies. The DRep vote cleared its threshold by nearly 19 percentage points. The SPO vote passed by 2.02 points — the narrowest margin among the three bodies.
The proposal was submitted in epoch 637 (approximately June 16, 2026). Ratification occurred on July 13, 2026, roughly four weeks later. Enactment followed at the next epoch boundary on July 18.
The Hard Fork Working Group, coordinated through Intersect MBO, managed logistics across Input Output, the Cardano Foundation, Emurgo, Midnight, and Ensurable Systems. While these entities contributed technical coordination, none held unilateral authority to approve or block the upgrade.
The Cardano Foundation delegated approximately 360 million ADA across 18 community DReps, distributing its voting weight rather than voting as a single bloc.
Van Rossem is best understood alongside other chains' governance approaches.
Tezos remains the benchmark for on-chain self-amendment. The network activated its 21st protocol upgrade (Ushuaia) on June 30, 2026, having completed all 21 upgrades through on-chain voting since its 2018 launch. No Tezos upgrade has produced a chain split. The 20th upgrade (Tallinn), activated in January 2026, cut block time to 6 seconds. Tezos's governance is baked into the protocol at genesis rather than retrofitted, which gives it a structural advantage in process maturity.
Ethereum continues to rely on off-chain coordination. Ethereum Improvement Proposals (EIPs) are debated in community calls, refined on GitHub, and implemented by client teams. Core developers make the final call on inclusion. There is no on-chain ratification step. The Pectra upgrade, which introduced EIP-7251 (raising the validator effective balance cap to 2,048 ETH), was enacted through this informal consensus process.
Cosmos uses on-chain governance for parameter changes and software upgrade signals, but the actual hard fork execution requires validators to manually update their node software. Governance votes are advisory rather than self-executing.
Cardano's model sits between Tezos and Cosmos: votes are binding and on-chain, but the system is new (first fully governed fork) and has not yet been tested under conditions of genuine community disagreement on a technical upgrade.
ADA traded at approximately $0.1663 in the 24 hours preceding the fork, representing a 5% gain against a broader market up 1.15%. Post-activation, the price fell to $0.162, a decline of 1.8%, consistent with a sell-the-news pattern. Trading volume dropped 54.81% to $179.93 million in the 24 hours following activation.
The muted market reaction may reflect the broader state of the Cardano ecosystem:
The high staking rate combined with low DeFi TVL suggests the network's economic activity is concentrated in consensus participation rather than application-layer usage.
Van Rossem's cryptographic and data structure improvements are explicitly preparatory for Ouroboros Leios, described in CIP-164. Leios operates as an overlay to Cardano's existing Ouroboros Praos consensus, adding endorser blocks and committee-based validation.
Current Cardano throughput: approximately 4.5 KB/s. Leios target: up to 200 KB/s — a potential 30–65x increase — without altering the underlying security model. The protocol aims to exceed 1,000 transactions per second.
Key milestones:
The next protocol upgrade after Van Rossem is designated "Dijkstra," which will introduce Leios to mainnet. Timeline for Dijkstra has not been formally announced.
The Van Rossem vote passed with comfortable margins. Other governance actions have not fared as well.
In June 2026, a treasury withdrawal proposal requesting 7.8 million ADA (approximately $2 million) for the Cardano Summit 2026 in Singapore failed to reach the 66.67% DRep threshold, receiving 65.21% support — falling short by 1.46 percentage points. The proposal had been reduced from an initial request of 14.07 million ADA (~$3.66 million) and included added oversight and milestone-based payments. The Cardano Foundation abstained from the vote. The summit was cancelled.
An alternative proposal from Emurgo to maintain a Singapore presence at TOKEN2049 passed separately.
This outcome illustrates both the system's functionality and its friction. The governance mechanism worked as designed — a proposal that did not achieve sufficient consensus was rejected. But the cancellation of the ecosystem's flagship conference raises questions about whether the current threshold structure is calibrated appropriately for discretionary spending decisions versus protocol upgrades.
Additionally, a 2026 Constitutional Committee election is underway (voting June 28 – July 23), with ten candidates competing for four seats. The CC's role in Van Rossem was limited to constitutional review (7-0 approval), but its composition matters for future contentious votes.
Van Rossem is a process milestone, not a product milestone. The technical changes — BLS12-381 multi-scalar multiplication, native arrays, multi-asset optimization — are incremental improvements whose value depends entirely on whether Leios delivers the promised throughput gains and whether developers build applications that use them.
The governance achievement is real. A network with 1.47 billion ADA in its treasury and over 60% staking participation ratified a protocol change without centralized coordination. That is a structural capability most chains do not possess.
But capability and performance are different things. With DeFi TVL below $72 million, trading volume contracting, and the flagship conference cancelled by its own governance process, the Cardano ecosystem faces a familiar question: can decentralized governance generate the economic activity that justifies its complexity? The Leios testnet and the 2026 Constitutional Committee election will provide data points. The market, so far, is not waiting.