What changes with BNB Chain’s Jenner hardfork?

BNB Chain has activated the Jenner hardfork on its BNB Smart Chain testnet, introducing a new payment processing mechanism that reserves 5% of block gas capacity for eligible transactions during periods of network congestion.

According to BNB Chain’s October 29 announcement, the upgrade introduces Payment Lane, millisecond block timestamps for smart contracts, and functionality for CAS20, a new compliant asset standard.

Payment Lane is the main feature of the upgrade and is designed to keep a portion of each block available for qualifying payments when other transactions compete for network capacity.

The hardfork is currently operating on testnet, with the mainnet rollout previously targeted for late November.

BNB Chain introduces reserved block capacity for payments

The new Payment Lane mechanism is introduced through BEP-703, which establishes separate gas accounting rules for eligible payments and general transactions.

During periods of heavy network activity, transactions compete for available block space under the network’s existing fee rules. Payment Lane changes this arrangement by reserving a portion of each block that general transactions cannot use.

BNB Chain has set the default reservation at 5% of a block’s gas limit, although qualifying payments are not restricted to that allocation.

For example, in a hypothetical block with a gas limit of 100 million, 5 million gas would be reserved for eligible payments, leaving up to 95 million available for general transactions.

If payment transactions consume 8 million gas, they can use capacity beyond the reservation, leaving 92 million for other transactions.

However, unused reserved capacity cannot be reassigned to general traffic. If eligible payments consume only 2 million gas, the remaining 3 million stays unused even when other transactions are waiting.

BNB Chain explained that the restriction prevents block producers from filling the entire block with general transactions while leaving qualifying payments out.

The upgrade follows the Pasteur hardfork activation in August, which introduced changes to bridge verification, validator authorization, and block construction.

As crypto.news previously reported, Pasteur introduced an optional block-building process under BEP-675 that allows validators to sign and broadcast proposed blocks before completing full execution checks.

Which transactions qualify for Payment Lane?

Under the new rules, BNB Chain recognizes two categories of transactions that can receive access to the reserved gas capacity.

The first includes transactions sent directly to payment contracts included on a governance-managed list. The second covers native BNB transfers involving a nonzero amount sent to accounts without deployed code.

Both categories must specify a destination address and use one of three supported transaction types: 0x00, 0x01, or 0x02.

Contract creation, blob transactions, and type 0x04 transactions remain classified as general traffic. Native BNB transfers to smart contracts or accounts with delegated code do not qualify under the ordinary transfer category.

For stablecoins, eligibility depends on whether the receiving contract appears on the approved payment list.

A transaction sent directly to a listed stablecoin contract can qualify, but one routed through an unlisted intermediary does not receive the same treatment simply because the intermediary eventually transfers the token.

The payment contract list will initially be empty. Governance can subsequently add or remove eligible contracts, including stablecoins and CAS20 tokens.

BNB Chain clarified that a token’s name, standard, or intended use for payments does not automatically make its transactions eligible.

How will BNB Chain manage the reserved capacity?

Governance will control both the payment contract list and the percentage of block gas reserved for eligible transactions.

Although the default allocation is 5%, the protocol allows governance to raise the reservation to a maximum of 10%.

The configuration is determined using the parent block’s state, preventing governance changes from altering transaction classification during the construction of an individual block.

Block builders must follow the allocation rules when assembling transactions, while validators are required to reject blocks that violate them.

Under BEP-675’s SendBidBlock process, execution checks occur during local block import after broadcast. Violations are handled through the builder revocation mechanism.

The reservation becomes effective in the block immediately following the hardfork activation block.

Payment Lane does not guarantee inclusion in a particular block or remove transaction fees. Eligible payments will continue competing with one another, particularly when their combined demand exceeds the reserved capacity.

Jenner upgrade follows growing BNB Chain activity

The latest upgrade arrives after BNB Chain recorded 1.51 billion transactions during the third quarter of 2026, an increase of 7.5% from the previous quarter.

Network revenue climbed 54% to $54.2 million, while average daily active addresses declined 14% to 2.10 million.

A separate quarterly ecosystem report showed that smart contract deployments reached 12.3 million, compared with 4.5 million in the preceding quarter.

Beyond Payment Lane, Jenner introduces millisecond block timestamps for smart contracts, giving applications access to more precise timing information.

The upgrade includes functionality for CAS20, although BNB Chain said further details about the standard’s availability would be announced separately.

Developers and payment providers can now use the testnet to check transaction destinations, supported transaction formats, and governance listing requirements.

BNB Chain has directed node operators to the Jenner upgrade documentation and reth-bsc v0.1.3 release notes for the relevant client upgrade instructions.