# Celo Mainnet Moves to op-reth **URL:** \ **Category:** Announcements\ **Created:** [July 10, 2026, 1:23pm UTC](https://forum.celo.org/t/celo-mainnet-moves-to-op-reth/13536 "2026-07-10T13:23:22Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![CeloCoreCo](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.celo.org/celocoreco/32/10907_2.png) [@CeloCoreCo](https://forum.celo.org/u/CeloCoreCo)\ **Post date:** [July 10, 2026, 1:23pm UTC](https://forum.celo.org/t/celo-mainnet-moves-to-op-reth/13536/1 "2026-07-10T13:23:22Z")
Hey Celo Community, Quick update on the op-geth to [op-reth transition we announced earlier](https://forum.celo.org/t/upcoming-transition-from-op-geth-to-op-reth-on-celo/13448): the testnet phase is done, and it went well. Celo Sepolia switched to op-reth on June 24 as planned, and it has been humming along ever since. Blocks are flowing, nodes are syncing, and nothing caught fire. A big thank you to everyone who migrated early and helped us validate the new client. With testnet behind us, we can now lock in the final date: **Celo Mainnet moves to op-reth on July 22, 2026.** ## **What Node Operators Need to Do** If you run a mainnet node, migrate to op-reth before July 22. op-geth will not support the L1 Glamsterdam hardfork, and nodes still running op-geth at activation will not be able to follow the canonical chain.The Celo-compatible op-reth release is out, and the docs are updated. Start with the[End of Support for op-geth](https://docs.optimism.io/notices/op-geth-deprecation) notice, which has the release and full instructions. The short version: - Follow[Run a node with Docker](https://docs.celo.org/infra-partners/operators/run-node) to get op-reth running. - Your old op-geth datadir will not carry over. op-reth uses a different on-disk format, so start it with an empty `DATADIR_PATH` and bootstrap from a published snapshot (`OP_RETH__SNAPSHOT=true`, required on mainnet). No L1 data migration needed. - Running an archive node or need L2 historical data? See[Running an archive node](https://docs.celo.org/infra-partners/operators/archive-node). - The[Configuration reference](https://docs.celo.org/infra-partners/operators/configuration) covers the `OP_RETH_\_\*` variables, and the latest images live in[celo-l2-node-docker-compose](https://github.com/celo-org/celo-l2-node-docker-compose). - Check [https://snapshots.celo.org/](https://snapshots.celo.org/) for available snapshots and more information regarding snapshots. - Prefer to build the image yourself? Build from the[celo/reth-v1.0.0 release](https://github.com/celo-org/celo-kona/releases/tag/celo%2Freth-v1.0.0). op-node itself remains fully supported, but we recommend adding or updating these flags on your op-node(s) when pairing it with op-reth: - `\--l2.enginekind=reth` - `\--syncmode=execution-layer` One friendly nudge: you can migrate today. Bootstrapping from a snapshot is quick (expect roughly 1 to 3 hours, depending on your config), so we recommend starting as soon as possible to be ready ahead of the switch on July 22. ## **RPC Providers and Infrastructure Partners** For most RPC consumers, this should be a non-event. op-reth speaks the same standard JSON-RPC as op-geth. If you run a bridge, indexer, or anything that leans on non-standard, tracing, or debug RPC methods, test against op-reth on Celo Sepolia now. It has been running the new client for two weeks, so it is the perfect place to shake out any differences before mainnet. ## **Where to Follow Along** - The Celo Forum - The[celo-l2-node-docker-compose](https://github.com/celo-org/celo-l2-node-docker-compose) repository - [Celo developer documentation](https://docs.celo.org) Thanks again to everyone who made the testnet migration smooth. One more switch to go. _The Engineering Team-Celo Core Co._