Ethereum’s Dencun Upgrade Completes Testnet Trials, Mainnet Comes Next

The final dress-rehearsal for Ethereum’s highly-anticipated Dencun upgrade was successful, with Dencun going live on the Holesky testnet on Feb. 7.

Prominent Ethereum developers and community members celebrated the fork’s smooth deployment, with EthPandaOps describing the Holesky launch as “uneventful.” The fork followed two other testnet deployment on Sepolia one week ago and Goerli three weeks.

“Holesky is finalized,” tweeted Paritosh, a devops engineer at the Ethereum Foundation. “Churn limit looks good so far and blobs are flowing smoothly! Next stop, mainnet!”

The mainnet deployment for Dencun is not currently scheduled, but Ethereum developers are expected to determine the date for its launch during the Feb. 8 All Core Devs Execution call.

“Based on historical hard forks, the mainnet hard fork should happen in around four weeks,” tweeted Beachonchain.eth, an Ethereum data provider.

Dencun will significantly reduce the costs associated with transacting on Ethereum, especially on Layer 2, by replacing gas-intensive calldata with lightweight Binary Large Objects (blobs) via EIP-4844 — also known as proto-danksharding. Unlike calldata, blobs do not compete with Ethereum transactions for gas and are not permanently stored on the blockchain, improving data availability.

“Dencun means more block space and lower costs,” Phillippe Schommers, the infrastructure director at Gnosis, told The Defiant. “Data that was previously stored indefinitely will be discarded after two weeks.”

Andy Bromberg, the CEO of the noncustodial wallet, Beam, told The Defiant that transaction fees could fall by between 66% and 80% once Dencun is live, Bromberg added that the upgrade benefits Ethereum by “enhancing user-friendliness and reducing barriers to entry and adoption.”

Scroll, a prominent Ethereum Layer 2 rollup, tweeted that “virtually all rollup teams are actively working to integrate support for 4844 data blobs.” Starknet, a rival Layer 2, tweeted that it is readying to ship an upgrade introducing support for EIP-4844, describing the introduction of blobs as driving “major cost reductions” for Starknet transactions.