Sepolia Post-Merge Upgrade Announcement | Ethereum Foundation Blog

  • The Sepolia testnet will undergo a post-merger execution layer (EL) update at block 1735371expected on August 17, 2022
  • The update will cause EL customers on the network to disconnect from peers who have not transitioned to proof of interest. It does not add any additional functionality beyond this.
  • Sepolia node operators must update their execution layer client before blocking 1735371.
  • A similar update is expected on Goerli and the Ethereum mainnet after these networks have moved to proof of interest.


To maintain a healthy peer list, nodes on the Ethereum execution layer will automatically disconnect peers that do not have the same update sequence as them. On the Ethereum mainnet, this means checking if a peer has risen to Frontier Thawing at block 200,000, then Homestead at block 1,150,000, and so on until the latest update, Gray Glacier, which happened at block 15,050,000. EIP-2124 specifies how this is handled. In typical network updates that are triggered by block height, this happens automatically because nodes use the block height of upcoming updates to filter peers.

For The Merge, this was not possible because the update was triggered using a total difficulty value rather than a block number. The reason for this choice is explained in EIP-3675:

Using a predefined block number for the hard fork is unsafe in this context due to the PoS fork selection taking precedence during the transition.

An attacker can use a minority of hash power to build a malicious chain fork that would satisfy the block height requirement. Then the first PoS block can be maliciously proposed on top of the PoW block of this opposing fork, becoming the head and undermining the security of the transition.

To protect the network from this attack scenario, difficulty accumulated by the chain (total difficulty) is used to trigger the update.

To minimize changes to the protocol during its most complex update since launch, the design for The Merge excluded EIP-2124 compatibility. This means that an additional update must now be made to add this. It is important to note that the only change introduced as part of this update is to specify a block number that nodes can use to identify peers that have gone through The Merge. No other features are introduced or deprecated as part of this update.

Update Information


This update will happen on Sepolia at block 1735371expected on August 17, 2022.

Note that a similar update will be announced for Goerli and mainnet once these networks have moved to proof of interest.

Ropsten will no to be updated as it is now considered deprecated, along with Rinkeby and Kiln. See this post for more details on their deprecated schedule.

Customer Releases

Only execution layer clients need to be updated for this update. Node operators can continue to run their current consent layer client release on Sepolia through the transition.

Note that client releases used for the Goerli/Prater merge all support this update on Sepolia. In other words, if you already downloaded a release for the Goerli/Prater merge, you can use that same version on Sepolia for this update.

Execution Layer

Upgrade Specifications

The specification for this change is tracked as part of the Paris specifications, under the FORK NEXT Upgrade section

Frequently Asked Questions

As a node operator, what should I do?

You should update your execution layer client to one of the versions listed above by August 16, 2022. Your consent layer client does not need to be updated.

As a staker, what should I do?

The validator set on Sepolia is allowed. If you are part of the current Sepolia validators, you must update your execution layer client to one of the versions listed above no later than August 16, 2022.

If you are not part of the current Sepolia validator set, you do not need to do anything at this time.

Goerli/Prater and main network validators will have to follow the same steps when this update is announced on those networks.

As an application or tool developer, what should I do?

Nothing, unless you also run node. If so, please update your execution layer client to one of the versions listed above by August 16, 2022.

As an Ethereum user or Ether owner, is there anything I need to do?

No. The Ethereum mainnet is not affected by this update. Even when this update is applied to mainnet, no action will be required.

Thanks to Justin Chrn for the original cover image and Tomo Saito for the modifications.



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