BNB Chain Accelerates opBNB With Major Block Time Reduction

• Fourier hardfork on BNB Chain halves the opBNB block time to 250 milliseconds, improving transaction responsiveness.
• opBNB now anchors derivation to finalized layer-1 blocks, while node fixes boost op-geth/op-node stability and sync reliability.

opBNB activated the Fourier mainnet hardfork, cutting block time from 500 milliseconds to 250 milliseconds. The rollout moved from testnet to mainnet at about 03:00 UTC, and Changpeng Zhao said completion followed about an hour later.

Fourier pairs faster blocks with protocol updates that refine finality handling and reduce reorg risk for sequencer operations. Node operators were instructed to upgrade op-geth to version 0.5.9 to stay aligned with the updated rules and client compatibility.

The upgrade also changes how opBNB references layer-1 data in derivation logic. Instead of tracking the latest layer-1 head, opBNB now anchors to finalized layer-1 blocks. The shift aligns with expected timing adjustments on BNB Smart Chain, where block times are set to fall to 450 milliseconds.

CNF earlier reported that BNB Chain 2025 upgrades cut average transaction fees by about 98% and improved network efficiency. The Lorentz upgrade in April and the Maxwell upgrade in June reduced average block times from about three seconds to about 0.75 seconds.

BNB’s Node Fixes and Client Stability Updates

Developers also shipped fixes aimed at node reliability and broader platform support. The update adds support for compiling opBNB with Golang version 1.24.x and improves compatibility for Windows operating systems.

Another patch addressed block number computation after prolonged shutdowns. Under older behavior, extended downtime could lead to incorrect block calculations after restart. The fix ensures long stops finalize correctly once the node resumes. Fourier also resolved a fastnode mode issue tied to missing state data in op-geth. In that setup, the op-node could receive an empty block root during engine API calls when the full state was not available. 

That condition could cause the op-node’s main loop to exit, stopping block synchronization. The updated behavior ensures op-node, in fastnode mode, waits for unsafe blocks from the peer-to-peer network and avoids requesting derivation from op-geth. Additional changes fixed a concurrent map usage problem in reference metrics and added the Fourier hardfork timestamp to mainnet parameters. 

Moreover, as mentioned in our previous story, BNB Chain has scheduled the Fermi hard fork for mainnet activation on January 14 after two months of testnet trials. GitHub documentation said the upgrade will cut block time to 250 milliseconds from about 750 milliseconds. The plan will introduce a new indexing mechanism that lets users access selected ledger data without downloading the full history.

BNB Chain’s end-of-2025 report cited a 40.5% year-over-year increase in total value locked across 2025, along with daily transaction volume averaging 10.78 million. BNB price action remained in focus as the upgrade cycle continued. The token broke the resistance zone, reaching an intraday high near $921 before pulling back to $907 at press time.