BNB Chain to Activate Pasteur Hard Fork on Aug. 25, Targeting Bridge Security and Higher Throughput

BNB Chain is set to activate its "Pasteur" hard fork on BNB Smart Chain (BSC) at 02:30 UTC on Aug. 25, 2026. The mandatory upgrade requires client v1.7.7 and introduces three protocol-level changes designed to strengthen cross-chain transfer security, curb validator governance workarounds, and expand block-processing capacity. All BSC mainnet nodes must upgrade to the new client ahead of activation. Regular users and most dApp developers are not expected to move funds or update application code. Key changes included in Pasteur BEP-682: tighter cross-chain verification BSC will begin validating validator signatures before accepting block data from another chain. The proposal also prevents specially constructed validator sets from inflating voting power by rejecting duplicate validator entries, ensuring the voting threshold reflects a true supermajority. BEP-695: consensus key and governance hardening When validators rotate consensus keys, the retired key will lose administrative privileges and no longer retain authority after rotation. Any pending slash evictions will follow the validator to the new key, closing an avenue to avoid penalties by switching keys. The update also prevents blacklisted addresses from bypassing restrictions through signature-based governance voting. These changes touch staking and governance system contracts but are implemented at the protocol/system-contract layer, so existing applications should not require migration. BEP-675: faster pre-executed block path for builders Builders will be able to submit blocks they have already executed. Validators can then sign and broadcast those blocks quickly, completing full verification outside the time-sensitive production path. This option requires builders to run full nodes because blocks must be fully executed before submission. Legacy block bids will remain available, though they provide builders less time to fill blocks. Test results on QANet BNB Chain tested Pasteur on QANet, an internal environment that mirrors BSC's cross-region validator setup, and reported notable performance gains under controlled conditions: - Critical-path processing time fell from 125 ms to 15 ms. - Average block gas used increased from 46.35M to 84.15M, against the current 100M limit. - Throughput rose from about 1,237 to about 2,324 transactions per second. - Block interval remained 450 ms and finality lag was unchanged. BNB Chain emphasized these are laboratory figures from QANet and that comparable mainnet improvements are not yet confirmed. After activation, operators and developers will monitor how much of the observed capacity and throughput gains carry into live traffic. Node operator checklist (required) - Install client v1.7.7 before 02:30 UTC on Aug. 25, 2026. Nodes that do not upgrade will fall out of sync. - Remove "[Eth] EnableBAL" from config.toml; leaving it in will cause the updated client to fail on startup. - Removing "[TxPool] OverflowPoolSlots" is recommended (the client will silently ignore this field if it remains). - Several command-line flags are now obsolete or inactive, including journalfile, enablebal and txpool.overflowpoolslots. Context Unlike recent BSC upgrades that focused primarily on shortening block times, Pasteur is aimed at better utilizing existing block capacity while closing security gaps related to cross-chain transfers and validator authority. Pasteur has been live on BSC testnet since July 21; its mainnet rollout will be the key test of whether QANet's throughput and capacity improvements hold up under real-world demand. Node operators, validators, and protocol-level builders should upgrade to client v1.7.7 and apply the configuration changes ahead of the activation deadline to avoid disruptions. Regular users and most application developers are not expected to take any action.