Upgrade 19 - Karst Hard Fork on Superchain chains [Action Required]

OP Labs has scheduled Upgrade 19 - Karst Hard Fork for OP Stack Superchain chains (which includes Mode, Metal, Zora).

Activation Timeline

• Testnet: Wed, Jun 17, 2026 at 16:00:01 UTC (1781712001)

• Mainnet: Wed, Jul 8, 2026 at 16:00:01 UTC (1783526401) (tentative)

Required Actions
If you are running external nodes for these networks, please ensure the following steps are completed before the fork time:

• Update op-node to version: v1.19.0 (Release) with flag --override.karst=1781712001 for testnet / --override.karst=1783526401 for mainnet.

• Update op-reth to version: v2.3.1 (Release). op-geth has reached end of support, so you must be running op-reth.

• Use updated genesis.json files from here:

  • Zora Testnet: https://api.conduit.xyz/file/v1/optimism/genesis/zora-sepolia-0thyhxtf5e

  • Zora Mainnet: https://api.conduit.xyz/file/v1/optimism/genesis/zora-mainnet-0

  • Metal Testnet: https://api.conduit.xyz/file/v1/optimism/genesis/metal-l2-testnet-3bbzi9kufn

  • Metal Mainnet: https://api.conduit.xyz/file/v1/optimism/genesis/metal-mainnet-0

  • Mode Testnet: https://api.conduit.xyz/file/v1/optimism/genesis/mode-sepolia-vtnhnpim72

  • Mode Mainnet: https://api.conduit.xyz/file/v1/optimism/genesis/mode-mainnet-0

• Conduit has updated our external node setup guide to reflect these changes -- you can use it as a reference for spinning up your node. Please reach out if you require a latest op-reth snapshot.

Questions?
If you have any questions, reach out through your usual support channels or at support@conduit.xyz.