Key Points
Karst goes live on Ronin mainnet on October 7 at 16:00:01 UTC! The upgrade brings Ethereum’s latest execution-layer improvements and a new system for managing Ronin’s core contracts. Nodes that aren’t upgraded before Karst activates will stop following the chain.
What this means for users: No action required. There will be no downtime and you can continue using Ronin as usual.
Developer Action Required: Builders as well as node operators should upgrade their clients, and builders should also test their applications against Karst on Saigon.
Ronin is getting an upgrade next week. The Karst upgrade will introduce Ethereum’s Fusaka hard fork to Ronin, bringing more efficiency and enabling a more streamlined approach to future upgrades. Here’s what’s happening:
What Is the Karst Upgrade?
The Karst Upgrade brings Ronin in line with Ethereum’s Fusaka hard fork, introducing the latest execution-layer improvements and a new system for managing Ronin’s core contracts.
Introduces the L2 Contract Manager: This makes it possible to upgrade Ronin’s core contracts in a single block, rather than relying on Ethereum multisig transactions or client-level changes
Upgrades Ronin’s L1 contracts to op-contracts/v7.0.0: This ensures Ronin’s bridge and rollup mechanics adhere to the newest and most secure standards provided by Optimism developers
For Ronin users, the upgrade will be seamless. No action is required and there will be no downtime. Saigon Testnet has also been running Karst since September 2, which has given builders and node operators time to test ahead of this mainnet activation.
What Changes for Builders
Most applications on Ronin will continue to work as usual. However, Karst introduces a few changes that builders should check before the upgrade goes live.
New ~16.8M gas cap starts October 7th
Once the Karst upgrade is complete, transactions will be capped at approximately 16.8 million gas. This may affect large batch operations, heavy multicalls, or unusually large contract deployments. Ethereum deposit transactions are exempt from this limit.
Note for users: This should not have any impact on your daily transactions. For example, a typical DEX swap may cost 10,000 gas, which is well-below the 16.8M limit.
Updated Costs for Cryptographic Operations
P256VERIFY will become roughly twice as expensive, which may affect applications using passkeys or WebAuthn-style authentication. MODEXP will also become more expensive, with a new 1024-byte input limit.
A Lower Pairing Limit
bn256Pairing will accept up to 300 pairs per call, down from 427. This is relevant for applications using zero-knowledge proof verification or BLS signature aggregation. Karst also introduces the new CLZ opcode. This is an additive change, but developers should update any tooling that parses bytecode or estimates gas.
Saigon has been running Karst since September 2. Builders can test their applications against the upgraded network before mainnet activation.
What Node Operators Need to Do
If you’re running a Ronin or Saigon node, you’ll need to update your node before Karst goes live.
Upgrade op-node
For the Karst override, use:
Ronin: --override.karst=1791388801
Saigon: --override.karst=1788364801
Upgrade op-reth
Upgrade to v2.2.3. This release also includes an upstream bug fix.
Update your genesis file
Download a fresh genesis.json for your network:
Ronin mainnet
Saigon
Still running op-geth?
You’ll need to migrate to op-reth before Karst. op-geth has reached the end of support and will no longer work after Karst activates. The external node setup guide has been updated with the new requirements. A recent op-reth snapshot is also available if you need one.
IMPORTANT: Nodes that aren’t upgraded before Karst activates will stop following the chain.
Karst Goes Live October 7
Karst marks another step in Ronin’s evolution, bringing the network closer to Ethereum’s latest standards while creating a stronger foundation for future upgrades. As usual, the Ronin Discord is open to builders and node operators looking for answers, support, or a place to discuss the upgrade. Feel free to join!