Cardano Activates van Rossem Hard Fork, Sets Stage for Ouroboros Leios Upgrade

Cardano has successfully activated its van Rossem hard fork on Saturday, upgrading the Cardano mainnet to version 11. This upgrade is expected to lower smart contract execution costs and lay the groundwork for Ouroboros Leios, a major scalability upgrade for the protocol.

The network moved from Protocol Version 10 in epoch 643 to Version 11 in epoch 644, according to onchain data from Cardanoscan.

Input Output wrote in their weekly development report that this upgrade 'lays the foundation for the next upgrade, the Dijkstra era hard fork, which will introduce Ouroboros Leios to Cardano.'

Ouroboros Leios is a scaling proposal for the Ouroboros proof-of-stake consensus used by Cardano, expected to launch in late 2026. Its goal is to drastically increase transactions per second without weakening Ouroboros' security guarantees.