BNB Smart Chain (BSC) has activated the Jenner hardfork on its testnet, introducing a dedicated payment mechanism designed to keep crypto transfers moving even when the network is congested. A hardfork is a coordinated protocol change that alters how a blockchain validates blocks, requiring nodes and validators to adopt the new rules to stay in sync. Announced on October 29, 2026, the upgrade introduces Payment Lane, a BEP-703 feature that reserves 5% of each block's gas for eligible payment transactions by default. It also adds millisecond-level block timestamps for smart contracts and lays the foundation for CAS20, a new Compliant Asset Standard. Payment Lane and CAS20 remain subject to governance approval before full activation, while the timestamp improvement takes effect with the hardfork itself.

Jenner hardfork is now live on BSC testnet! What the upgrade entails: 🔸 Payment Lane, reserving 5% of block gas by default for eligible payments. 🔸 Millisecond block timestamps for smart contracts. 🔸 Functionality for CAS20, a new Compliant Asset Standard. Payment Lane and CAS20 will go through governance before being fully enabled. More details to follow. Read the full upgrades 👇

— BNB Chain (@BNBCHAIN) October 29, 2026

The full upgrade details are available in BNB Chain's official announcement.

Payment Lane Reserves 5% of Block Gas

The centerpiece of the Jenner upgrade is Payment Lane, introduced as BEP-703. Under the default configuration, the system sets aside 5% of the gas in each block for eligible payment transactions, regardless of how high payment demand is at any given moment. Gas is the unit that measures computational work on a blockchain, and each block carries a finite amount of it, so during periods of heavy usage transactions compete for that fixed space. The reservation is intended to ensure that payment transactions can proceed without interruption during periods of network congestion. General transactions cannot draw on the reserved slice: in a hypothetical block with a 100 million gas limit, 5 million gas would be reserved for payments while general transactions could use up to 95 million.

Importantly, the mechanism is not a hard cap on payment activity. Under standard fee rules, eligible payments can still consume the remaining block space even after the reserved allocation is in place.

Eligibility Rules and Governance Oversight

Not every token transfer is routed into the reserved lane. Regular accounts qualify for native transfers between accounts, and a token contract becomes eligible once it is added to a list of regulated payments. That list starts with no tokens on it and can be expanded later to include stablecoins or CAS20 coins, making the list's eventual composition one of the concrete items to track as the upgrade advances. Direct transfers involving an approved stablecoin contract could also qualify. If a transaction is routed through a smart contract that is not on the list, however, it continues to be treated as general traffic.

Governance can also adjust the size of the reserved share, which is capped at 10% at the protocol level. Both Payment Lane and CAS20 must still pass through governance steps before they are fully enabled, BNB Chain noted.

Millisecond Timestamps for Smart Contracts

Jenner also gives smart contracts time resolution at the millisecond level. Until now, contracts could only work with second-granularity time measurements. Block timestamps—the time values attached to each block—are what smart contracts read to gauge the passage of time, so finer granularity gives that signal more precision. Applications that require fine time resolution, such as trading systems, quoting, and short-lived automated DeFi logic, stand to benefit from the improved time precision. BSC block values are not increased by the change; instead, it provides developers with a more accurate indication of when each block is generated.

CAS20 Expands the Token Framework

The hardfork additionally introduces functionality for CAS20, short for Compliant Asset Standard. In addition to traditional BEP-20 tokens, the framework is expected to support stablecoins and tokenized real-world assets, broadening BNB Chain's token framework. The standard also connects to Payment Lane's design: the eligibility list for the reserved gas slice can be expanded to include stablecoins or CAS20 coins, meaning assets issued under the new framework could be routed into the payment lane once governance adds them.

Testing on Testnet Before Production

The testnet deployment lets users and developers test transaction classification, supported transaction types, and integration behavior before the features reach production. Validators are expected to reject blocks that do not comply with the gas-allocation rules, with the allocation itself handled by the block builder. By integrating Payment Lane into block validation, BNB Chain positions the feature as a protocol-level guarantee rather than an option limited to wallets or applications. From here, the milestones to watch are the governance processes that would fully enable Payment Lane and CAS20 and the features' eventual transition to production. More details will be shared as the features move toward full activation.