TL;DR

Over the past year, BNB Chain has focused on one clear direction: speed.

• The Fermi Hard Fork pushed BSC to ~0.45 second block times
• The Maxwell Hard Fork stabilized performance around ~0.75 seconds
• The Lorentz Hard Fork reduced the block interval from ~3 seconds to ~1.5 seconds

The Osaka/Mendel hard fork builds on these upgrades.

Instead of pushing block times further, this upgrade focuses on refining how the network behaves under real usage and improving overall consistency.

Osaka/Mendel hard fork happens on April 28, 2026 at 02:30 UTC.

What Osaka/Mendel brings to BNB Chain

Osaka/Mendel is a network upgrade made up of 9 BEPs, combining selected ecosystem improvements with changes built specifically for BNB Chain.

• 6 Ethereum EIPs adopted
• 2 BNB Chain–specific upgrades introduced

Each change is included based on what improves performance and usability in practice, not just for alignment.

The goal of this hard fork is better execution, more stable performance, and faster finality that holds up under real usage.

Refining performance without changing how you build

Fermi and Maxwell made BNB Chain fast. Osaka/Mendel builds on that by tightening how the network behaves under real usage, while selectively bringing in improvements where they actually add value.

When blocks are produced in under a second, even small inefficiencies start to matter. Gas spikes, heavy computation, or inconsistent execution can create friction quickly.

This upgrade focuses on removing that friction.

More predictable gas and execution

Several changes tighten how computation behaves onchain.

• Upper bounds on heavy operations like modular exponentiation
• Caps on transaction gas limits
• Adjustments to gas costs so they better reflect real usage

For developers, this reduces unexpected behavior.

For users, it leads to more consistent transactions, even during high activity.

Small upgrades that improve the engine

A new opcode (CLZ) is introduced for counting leading zeros.

It’s not something most users will notice, but it gives developers more efficient tools at the execution level.

These kinds of changes improve performance without changing how apps look or feel.

Keeping blocks stable under pressure

Execution limits are tightened with a clear cap on block size.

This prevents blocks from becoming too heavy to process, which helps maintain consistent performance as activity grows.

It’s a quiet change, but an important one for long-term scalability.

Better support for real-world cryptography

Gas costs for secp256r1 cryptography are updated.

This makes it easier to integrate with systems outside the typical Ethereum stack, especially in cases where different cryptographic standards are used.

BNB Chain–specific upgrades that go beyond standard updates

Two changes are designed specifically around how BNB Chain operates:

• Blob transactions are limited by block number → Helps prevent large data-heavy transactions from impacting block performance
• Fast Finality is improved using an in-memory voting pool → Transactions confirm faster and with more reliability

These upgrades are designed around real usage on BNB Chain, focusing on reducing latency and keeping performance consistent.

This is where the upgrade becomes noticeable in practice. Faster, more reliable confirmations reduce waiting and uncertainty.

Cleaner tooling for developers

A new JSON-RPC method (eth_config) is introduced.

This gives developers better visibility into node configuration, making debugging and infrastructure work more straightforward.

What this upgrade changes in practice

Most users won’t notice a single feature tied to Osaka/Mendel, but they will notice the outcome:

• More consistent transaction behavior
• Faster and more reliable confirmations
• Fewer edge-case issues during high activity

For developers:

• More predictable execution
• Easier gas modeling
• Better tooling visibility

A more stable foundation for what comes next

BNB Chain has already shown it can reach sub-second performance.

Osaka/Mendel reinforces that performance by tightening execution and improving consistency at the protocol level.

It tightens the system without adding unnecessary complexity, giving both developers and users a more reliable experience.

What this sets up next

Fermi, Maxwell, and Pascal pushed performance forward, Osaka/Mendel continues that momentum by bringing in selected upgrades and refining how the network operates under real conditions.

It combines ecosystem-level improvements with BNB Chain: specific optimizations, keeping the network fast while ensuring changes are applied where they actually add value.