BSC release v1.6.4 has been published. This is a mandatory upgrade for all BSC Mainnet nodes in preparation for the upcoming Fermi hard fork.
All node operators must upgrade their mainnet nodes before the fork activation time, scheduled for January 14, 2026, at 02:30:00 AM UTC. For those running v1.6.3, the upgrade only requires a binary replacement.
Fermi Hard Fork Highlights
The primary goal of this hard fork is to reduce the block interval from 0.75 seconds to 0.45 seconds. This change is introduced via two new proposals:
BEP-619: Short Block Interval Phase Three: 0.45 Seconds.
BEP-590: Extended Voting Rules for Fast Finality Stability.
Other Notable Changes
Bug Fixes:
• The transaction lifetime in the TxPool has been reverted to 3 hours, a duration considered more stable for non-validator nodes.
• Windows compatibility has been restored by downgrading the `bls-eth-go-binary` dependency.
• Support for the non-functional `--multidatabase` flag has been removed to avoid confusion.
Improvements:
• For better client version tracking, the block's `extraData` now includes the commit ID.
• A resource leak issue has been addressed by implementing an auto-unsubscribe mechanism for `transactionReceipts` subscriptions.
• State prefetching has been improved by using a cached reader, enhancing node performance.
• A new metric has been added to track validator vote counts.
v1.6.4 is the release for the BSC Mainnet [Fermi hard fork](https://forum.bnbchain.org/t/bnb-chain-roadmap-mainnet/936#p-1418-h-1-fermi-wip-8), which is expected to be activated at **2026-01-14 02:30:00 AM UTC**. All BSC Mainnet nodes **must upgrade to v1.6.4 before the hard fork time**. Upgrading from v1.6.3 only requires a **binary replacement**. v1.6.4 includes two BEPs, primarily aimed at reducing the block interval from 0.75 seconds to 0.45 seconds: * [BEP-619: Short Block Interval Phase Three: 0.45 Seconds](https://github.com/bnb-chain/BEPs/blob/master/BEPs/BEP-619.md) * [BEP-590: Extended Voting Rules for Fast Finality Stability](https://github.com/bnb-chain/BEPs/blob/master/BEPs/BEP-590.md) In addition to the block interval reduction, several other key parameters will be updated. Please refer to **[BEP-619: Parameter Changes](https://github.com/bnb-chain/BEPs/blob/master/BEPs/BEP-619.md#51-parameter-changes)** for details. Beyond the hard-fork-related changes, this release also includes multiple improvements and bug fixes. For the full list, please refer to the changelog below. ## Changelog ### FEATURE * [#3466](https://github.com/bnb-chain/bsc/pull/3466) config: update BSC Mainnet hard fork time: Fermi * [#3454](https://github.com/bnb-chain/bsc/pull/3454) eth: support fetching commit ID information from extra data ### BUGFIX * [#3448](https://github.com/bnb-chain/bsc/pull/3448) TxPool: revert transaction lifetime back to 3 hours * [#3457](https://github.com/bnb-chain/bsc/pull/3457) cmd/geth: remove support for the `multidatabase` flag * [#3467](https://github.com/bnb-chain/bsc/pull/3467) go.mod: downgrade bls-eth-go-binary to restore Windows compatibility ### IMPROVEMENT * [#3445](https://github.com/bnb-chain/bsc/pull/3445) eth: improve prefetching by using cached reader * [#3459](https://github.com/bnb-chain/bsc/pull/3459) feat: implement auto-unsubscribe for `transactionReceipts` * [#3468](https://github.com/bnb-chain/bsc/pull/3468) metric: add metric for vote count ## Assets | Assets | Sha256 Checksum | | :-----------: |------------| | mainnet.zip | 0019dfc4b32d63c1392aa264aed2253c1e0c2fb09216f8e2cc269bbfb8bb49b5 | | testnet.zip | 0019dfc4b32d63c1392aa264aed2253c1e0c2fb09216f8e2cc269bbfb8bb49b5 | | geth_linux | c02e80e483c73d1e805856f72205a777c03699e4ecb8b1b87c72586d309c4fb6 | | geth_mac | daf11f9591ab6b4666b1b0be8041bfde0c26f2b1cf4aba83f0c9589a197b1fef | | geth_windows | 4e2f2633c632df9c8d4e90263da331f067b45646f8c98a4f5c364626228a87a5 | | geth_linux_arm64 | 45234dca7c564c1b40ef09c4a9321a4eca6d3a98273438cc9c5ed64a14c8bb8b |