- The Sepolia testnet will receive a post-merge execution layer (EL) enhancement at block 1735371, anticipated on August 17, 2022
- This enhancement will result in EL clients on the network severing connections with peers that have not migrated to proof-of-stake. It does not introduce any further functionality apart from this.
- Operators of Sepolia nodes are required to update their execution layer client before the block 1735371.
- A comparable enhancement is anticipated for Goerli and the Ethereum mainnet once these networks have moved to proof-of-stake
Background
To ensure a robust peer list, nodes on Ethereum’s execution layer will automatically disconnect from peers who do not follow the same upgrade progression. On the Ethereum mainnet, this implies verifying whether a peer upgraded to Frontier Thawing at block 200,000, followed by Homestead at block 1,150,000, and so forth to the latest enhancement, Gray Glacier, which occurred at block 15,050,000. EIP-2124 details how this is managed. In standard network upgrades, which are activated by block height, this occurs automatically as nodes utilize the block height of upcoming enhancements to filter their peers.
For The Merge, this was not feasible because the enhancement was initiated using a total difficulty value instead of a block number. The reasoning behind this decision is outlined in EIP-3675:
Using a predefined block number for the hard fork is risky in this situation due to the PoS fork choice taking precedence during the transition.
An attacker may leverage a minority of hash power to construct a malicious chain fork that meets the block height requirement. The first PoS block might then be maliciously proposed on top of the PoW block from this hostile fork, taking precedence and undermining the transition’s security.
To safeguard the network from this attack scenario, the difficulty amassed by the chain (total difficulty) is employed to initiate the enhancement.
To limit adjustments to the protocol during its most intricate upgrade since inception, the design for The Merge omitted EIP-2124 compatibility. Thus, an additional upgrade is now necessary to incorporate this feature. It is crucial to emphasize that the sole alteration introduced in this enhancement is determining a block number that nodes can utilize to recognize peers who have successfully gone through The Merge. No other features are added or removed in this upgrade.
Upgrade Information
Timing
This enhancement will take place on Sepolia at block 1735371, anticipated on August 17, 2022.
Please note that a similar enhancement will be declared for Goerli and mainnet following the transition of these networks to proof-of-stake.
Ropsten will not receive an upgrade as it is now regarded as deprecated, along with Rinkeby and Kiln. See this post for additional details on their deprecation timeline.
Client Releases
Only execution layer clients are required to be updated for this enhancement. Node operators may continue utilizing their current consensus layer client version on Sepolia throughout the transition.
It is important to note that client releases utilized for the Goerli/Prater merge are all compatible with this enhancement on Sepolia. In simpler terms, if you have already downloaded a release for the Goerli/Prater merge, you may use that same version on Sepolia for this enhancement.
Execution Layer
Upgrade Specifications
The specifications for this modification are tracked as part of the Paris specifications, under the FORK NEXT Upgrade section.
FAQ
As a node operator, what should I do?
You should update your execution layer client to one of the versions specified above prior to August 16, 2022. Your consensus layer client does not require an update.
As a staker, what do I need to do?
The validator set on Sepolia is permissioned. If you are among the present Sepolia validators, you must upgrade your execution layer client to one of the versions noted above by August 16, 2022 at the latest.
If you are not part of the current Sepolia validator set, you need not take any action at this time.
Goerli/Prater and mainnet validators will need to adhere to the same procedures when this enhancement is announced on those networks.
As an application or tooling developer, what should I do?
Nothing, unless you are also operating a node. If that is the case, please upgrade your execution layer client to one of the versions specified above before August 16, 2022.
As an Ethereum user or Ether holder, is there anything I need to do?
No. The Ethereum mainnet remains unaffected by this enhancement. Even when this enhancement is enacted on mainnet, no action will be required.
Thank you to Justin Chrn for the original cover image and Tomo Saito for the alterations.