The third hard fork of the Conway era, enacted at the start of epoch 644 on July 18, 2026. It moved mainnet from protocol version 10 to 11 without opening a new ledger era, so governance and the ledger rules stayed as Plomin left them. The name honors Max van Rossem, a DRep who helped shape the Cardano Constitution and died in 2025.
The upgrade is a smart contract release. It extends Plutus V3 with new builtins: multi-scalar multiplication on BLS12-381 (CIP-133), a native array type (CIP-138), modular exponentiation (CIP-109), a faster dropList (CIP-132) and better handling of multi-asset values (CIP-153). A Plutus cost model update, enacted separately on June 18, 2026, set the prices for the new primitives and lowered the cost of several existing ones.
van Rossem was the first hard fork proposed, debated and ratified entirely through CIP-1694 governance. The hard fork initiation action passed with 77.6 percent of DRep stake, 52.7 percent of stake pool stake and a Constitutional Committee majority. The next hard fork is Dijkstra, which opens a new ledger era.
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- Hard ForkA network upgrade that changes the blockchain's rules in a way older software versions no longer understand; every node has to update before the change takes effect.View term
- Hard Fork InitiationA CIP-1694 governance action type that schedules and triggers a Cardano hard fork by on-chain vote.View term
- Conway EraThe Cardano ledger era that brought on-chain governance under CIP-1694 to mainnet.View term
- ChangThe hard fork on September 1, 2024 that activated the Conway era and brought CIP-1694 governance live on Cardano.View term
- PlominThe Conway-era hard fork on January 29, 2025 that turned on the remaining CIP-1694 governance actions.View term
- DijkstraThe next Cardano ledger era and hard fork, named after Edsger Dijkstra. Its first phase, targeted for late 2026, brings Linear Leios and nested transactions, a second phase adds Peras.View term
- Plutus CoreCardano's on-chain smart-contract runtime. Higher-level languages (Plinth, Aiken) compile down to Plutus Core for execution.View term
- PlutusCardano's smart contract platform. The name covers the Plutus Core language that runs on-chain and the tooling that compiles higher-level languages down to it.View term