The 2020 hard fork brought staking, stake pools and decentralized block production, while Input Output now targets a 5x to 20x throughput increase with Ouroboros Leios later in 2026.
Cardano is marking six years since the Shelley upgrade, the July 2020 hard fork that introduced staking (locking tokens to help secure a network), stake pools and decentralized block production to the network. The milestone highlights a shift from the earlier Byron era, when the Cardano mainnet and ADA launched in September 2017, toward a more decentralized operating model. The Cardano community X account said Shelley turned staking rewards, stake pools and decentralized block production into core parts of the chain, adding that "The chain hasn't stopped since." The post cited 439 epochs, 9.25 million blocks and 190 million slots. Cardano began as a federated network with only a few nodes, and the Byron reboot in early 2020 helped prepare the system for decentralization with a newly rebuilt node architecture. Shelley then added delegation and a decentralized ledger tied to a new economic system. In Q1 2021, the stake pool operator (SPO) community began producing 100% of new blocks. Cexplorer data currently shows 2,882 pools and 21.56 billion ADA in live stake. The anniversary comes as Cardano prepares for what it describes as its biggest scaling upgrade yet. Ouroboros Leios, now running on the public Musashi Dojo testnet, is designed to raise base-layer throughput and is structured across five phases: Earth, Water, Fire, Wind and Void. Input Output is targeting an initial 5x to 20x increase in throughput capacity, with a mainnet hard fork planned for later in 2026. The Van Rossem hard fork, which went live this July, is intended to set up the later Dijkstra era hard fork that will bring Ouroboros Leios to Cardano.