It adds new capabilities to Plutus, which platform developers use to write Cardano’s smart contracts, and unifies the built-in features available across the platform’s three versions, so older applications get newer features.
The upgrade also tightens several of the ledger’s validation rules, including one that guarantees that no two stake pools can reuse the same cryptographic identity key.
“As well as Plutus improvements and Plutus Cost Model improvements, this upgrade lays the foundation for the next upgrade, the Dijkstra-era hard fork, which will introduce Ouroboros Leios to Cardano,” Input Output wrote in a development report on Friday.
Ouroboros Leios is a scaling proposal for the proof-of-stake consensus model that Cardano runs. It is expected later in 2026 and aims to greatly increase the number of transactions per second without weakening the protocol’s security guarantees.
Van Rossem is the procedural foundation of Ouroboros, both in the changes it sends and in the precedent it sets: that Cardano can now upgrade itself by voting.
The hard fork is named after Max van Rossem, a Cardano government contributor who helped shape the network’s constitution and died in October 2025.
What the hard fork means for a Cardano user
There are no visible changes to anyone casually holding or using the ADA. Transactions work the same, wallets don’t need updating, and the fee to send ADA is unchanged. The upgrade does not change how the network looks or feels to use.
