- The Sepolia testnet is set for a post-merge execution layer (EL) upgrade at block 1735371, which is anticipated on August 17, 2022
- This upgrade will disconnect EL clients on the network from peers who have not migrated to proof-of-stake. There is no new functionality being introduced beyond this change.
- Node operators on Sepolia must update their execution layer client prior to block 1735371.
- A similar upgrade is projected for Goerli and the Ethereum mainnet after these networks complete their transition to proof-of-stake
Background
To ensure a stable peer list, nodes within Ethereum’s execution layer will disconnect from peers that do not share the same upgrade sequence. For the Ethereum mainnet, this involves verifying that a peer upgraded to Frontier Thawing at block 200,000, then to Homestead at block 1,150,000, and proceeding through to the most recent upgrade, Gray Glacier, at block 15,050,000. EIP-2124 outlines how this process is conducted. Typically, upgrades set off by a block height automatically occur as nodes adjust their peer filtering based on upcoming upgrade heights.
However, for The Merge, using a total difficulty value instead of a block number for the upgrade was necessary. The reasoning behind this decision is discussed in EIP-3675:
Using a predetermined block number for the hardfork poses safety challenges, as the PoS fork choice would dominate the transition process.
An attacker could potentially leverage a minority of hash power to create a malicious fork chain that meets the block height criteria. Consequently, a maliciously proposed PoS block could then be placed atop a PoW block from the adversarial fork, leading to security issues during the transition.
To safeguard the network against such attack scenarios, the upgrade is triggered based on the accumulated difficulty of the chain (total difficulty).
To limit protocol adjustments during its most intricate upgrade since inception, The Merge’s design did not incorporate EIP-2124 compatibility. Thus, a follow-up upgrade is now necessary to enable this feature. It’s crucial to note that the only alteration resulting from this upgrade is the establishment of a block number that nodes may use to identify peers that have undergone The Merge. No additional functionality will be introduced or deprecated in this upgrade.
Upgrade Information
Timing
This upgrade is scheduled for Sepolia at block 1735371, anticipated on August 17, 2022.
A similar upgrade announcement will follow for Goerli and mainnet post their transition to proof-of-stake.
Ropsten will not receive an upgrade as it has been deemed deprecated, alongside Rinkeby and Kiln. Refer to this post for additional information regarding their deprecation timeline.
Client Releases
Only execution layer clients require updates for this upgrade. Node operators can continue utilizing their existing consensus layer client on Sepolia throughout the transition.
It is worth noting that client releases used for the Goerli/Prater merge all support this upgrade on Sepolia. This means that if you have already downloaded a release for the Goerli/Prater merge, that same version is applicable for this upgrade on Sepolia.
Execution Layer
Upgrade Specifications
The specifications for this change are documented as part of the Paris specifications, specifically under the FORK NEXT Upgrade section.
FAQ
As a node operator, what should I do?
You should upgrade your execution layer client to one of the aforementioned versions before August 16, 2022. There is no need to upgrade your consensus layer client.
As a staker, what do I need to do?
The validator set on Sepolia is permissioned. If you are among the current Sepolia validators, you must update your execution layer client to one of the versions listed earlier by August 16, 2022, at the latest.
If you are not part of the current Sepolia validator set, there is no action required on your part at this time.
Validators on Goerli/Prater and on mainnet will need to adhere to the same steps when this upgrade is announced for those networks.
As an application or tooling developer, what should I do?
You don’t need to take any action unless you are also running a node. If that is the case, please upgrade your execution layer client to one of the versions specified earlier by August 16, 2022.
As an Ethereum user or Ether holder, is there anything I need to do?
No, this upgrade does not impact the Ethereum mainnet. Even when the upgrade reaches the mainnet, no action will be necessary.
Thank you to Justin Chrn for the original cover image and Tomo Saito for the modifications.
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