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As the ecosystem matures, we are transitioning full execution client support to op-reth and moving from op-program to kona-client.

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What this means

  • op-geth is supported through May 31st, 2026. Security patches and critical bug fixes will continue to be issued during this window, after which support ends.
  • New feature development, including the next Karst hardfork, will happen on op-reth only.
  • op-program is also reaching end-of-support. The fault proof program is transitioning from op-program to kona-client.
  • Current op-program deployments are expected to remain usable until the next hardfork, Karst. Chain operators will need to migrate to kona-client at Karst.
  • kona-node is not required for cannon-kona. You can run kona proofs with your existing op-node setup. kona-node is a separate, optional component and is not part of the fault proof program migration.
  • op-node is not being deprecated.

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Action required

op-geth will not support the L1 Glamsterdam hardfork. Chains still running op-geth at activation will not be able to follow the canonical chain.

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Node Operators

All node operators should migrate to op-reth as soon as possible. For more details, see op-reth configuration in the resources section below.
op-geth reaches end-of-support in May 31st, 2026. Glamsterdam will break compatibility with op-geth.
Syncing op-reth takes time. Start early to allow adequate validation before the hardfork window.
Start syncing an op-reth node alongside your existing op-geth node and take a snapshot. Validate sync correctness over a meaningful window—compare block hashes, state roots, and RPC outputs. Once confident, migrate production traffic to op-reth. For OP Mainnet snapshots, you can find snapshots here.

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Chain Operators

As soon as op-reth is fully synced, take a snapshot. Refresh it regularly as Glamsterdam approaches. Syncing an op-reth node as soon as possible helps ensure a snapshot is available for other validators on your chain so they do not need to sync from scratch.

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Permissionless Chain Operators

In parallel, the fault proof program is moving from op-program to kona client. Current op-program deployments are expected to remain usable until the next hardfork, Karst, when chain operators will need to migrate to kona-client. Optimism will handle the onchain prestate updates for managed chains. If you operate a permissionless fault proof chain, watch for a separate notice with specific steps.

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Resources