Ethereum’s Dencun Upgrade Goes Live, But Fails to Finalize on Testnet

Ethereum’s much-awaited Dencun upgrade went live on the Goerli testnet earlier Wednesday but failed to finalize in the expected time.

The upgrade was pushed at 6:32 UTC, blockchain data shows, but did not initially finalize on the testnet.

A few hours later, Ethereum core developer Parithosh Jayanthi confirmed that the chain was finalizing again, and told CoinDesk over Telegram that the issue was due to a bug, now patched, in Prysm nodes.

Finality refers to irreversibility once a transaction has been confirmed and added to a block in a blockchain network. A testnet is a network that mimics real-world blockchains and is used to test applications and important upgrades before they can be pushed live on a mainnet.

Dencun’s implementation of Goerli is part of a three-phased approach to eventually enacting a new, less costly method of storing data on the main Ethereum blockchain.

That method, “proto-danksharding,” is a mechanism that will add capacity for data availability as well as help reduce the cost of transactions for layer-2 blockchains. These auxiliary networks have proliferated in the past year as an alternative to processing transactions on the main Ethereum blockchain, but analysts say their growth is hampered by the steep data costs under the current setup.

The next phase will happen sometime in the next few weeks, with an upgrade to the Sepolia testnet, followed by the Holesky testnet.

Dencun will be the biggest upgrade – technically a “hard fork” in blockchain terminology – for Ethereum since the Shapella upgrade last March, which enabled the withdrawals of staked ether stETH. That milestone marked the second step for Ethereum’s transition to a proof-of-stake blockchain, away from the more energy intensive proof-of-work chain that it was before the Merge.

UPDATE (Jan. 17, 08:15 UTC): Adds additional details.

UPDATE (Jan. 17, 14:49 UTC): Updates that the blockchain is finalizing again.