Cardano has activated its van Rossem hard fork as of Saturday, upgrading the Cardano mainnet to version 11, which is expected to lower smart contract execution costs and lay the groundwork for Ouroboros Leios, a major scalability upgrade for the protocol.
Onchain data from Cardanoscan shows the network moved from Protocol Version 10 in epoch 643 to Version 11 in epoch 644.
cointelegraph.com