The long-awaited London enhancement is now prepared for deployment on the Ethereum testnets! This enhancement will initially launch on Ropsten, at block 10499401, which is anticipated to occur around June 24, 2021.
This enhancement follows the Berlin, which was activated just a few months earlier on the Ethereum mainnet. By initiating work on London while Berlin was being implemented, client teams could release this network upgrade at an unprecedented pace! The enhancement includes the following EIPs:
The Ethereum Cat Herders have published a blog entry detailing these EIPs.
It is important to highlight that EIP-1559, while compatible with the existing transaction format, implements modifications to the block header, introduces a new transaction type, provides new JSON RPC endpoints, and alters the behavior of clients in various aspects (mining, transaction pool, etc.). It is strongly advised that projects become acquainted with the EIP. A more comprehensive list of resources related to EIP-1559 can be located here.
London Timing
Currently, only the testnets (Ropsten, Goerli, Rinkeby) have been slated for London. Once the enhancement is successfully activated on these networks, a block will be designated for the Ethereum mainnet and will be communicated on this blog and in other channels.
The release timeline is as follows:
| Network | Block Number | Expected Date |
|---|---|---|
| Ropsten | 10499401 | June 24, 2021 |
| Goerli | 5062605 | June 30, 2021 |
| Rinkeby | 8897988 | July 7, 2021 |
| Mainnet | TBD once testnets fork successfully. | TBD once testnets fork successfully. |
Note: the Kovan network will be upgraded at a subsequent date, probably after the Mainnet block has occurred.
Ethereum node operators should upgrade their nodes before the fork block on the networks they wish to engage in. Given the variability in block times, it is advised to update several days ahead of the anticipated date. Refer to the section below for the suitable client versions to upgrade to.
Client Versions
To remain compatible with the London enhancement, node operators must upgrade the client version they are running. The versions, enumerated below for each client, support London across test Ethereum networks. Another release will be issued by each client once the mainnet fork block has been determined.
Note: the OpenEthereum client will be discontinued after the London enhancement. The team is coordinating with Erigon to ensure a smooth transition for users. Additional information can be found here.
FAQ
As an Ethereum user or Ether holder, is there anything I need to do?
The enhancements mentioned in this post solely impact the Ethereum testnets, and not the Ethereum mainnet. If you are merely a user of the Ethereum mainnet, there is nothing you need to do at this time.
As a Ropsten miner or Goerli/Rinkeby validator, what actions must I take?
First, acquire the latest version of your Ethereum client, as outlined in the table above. Then, you will need to manually adjust your gas limit target to double what it currently is. This is necessary because once London is operational, the block size will be increased and EIP-1559 will maintain blocks at approximately 50% capacity.
For instance, if prior to London you were a Ropsten miner aiming for a block size of 8,000,000 gas, you will now need to aim for a 16,000,000 gas limit to retain the same volume of transactions per block, on average. If you do not modify your gas limit target, you will begin to decrease the block size on the network. The table below specifies the particular parameter you need to update according to your client.
As a non-validating or mining node operator, what actions should I take?
Download the latest version of your Ethereum client, as outlined in the table above, and remain vigilant for the mainnet upgrade announcement in the upcoming weeks.
What occurs if I am a miner or node operator and I do not engage in the upgrade?
If you are utilizing an Ethereum client that has not been updated to the latest version (listed above), your client will sync to the pre-fork blockchain once the upgrade takes place. You will be stuck on an incompatible chain following the old rules and will be unable to send Ether or function on the post-upgrade Ethereum network.
What is a network upgrade in Ethereum-land?
A network upgrade is a modification to the foundational Ethereum protocol,creating new regulations to enhance the system. The distributed characteristic of blockchain systems complicates a network upgrade. Network enhancements in a blockchain necessitate collaboration and dialogue with the community, along with the developers of the various Ethereum clients so the transition can occur seamlessly.
What transpires during a network upgrade?
Once the community reaches a consensus regarding which modifications should be incorporated in the upgrade, protocol alterations are documented in the different Ethereum clients such as geth, Erigon, Besu, and Nethermind. The protocol amendments are engaged at a designated block number. Any nodes that have not been updated to the new regulations will remain on the old chain where the prior rules persist.
What’s with “London”?
Following Istanbul, we ran out of titles for our forthcoming network upgrades. It was proposed to utilize Devcon city names for upgrades, and we adopted this suggestion! London is the city where Devcon 1 occurred. It was subsequent to the Berlin Devcon 0.
Thank You!
A heartfelt thank you to everyone who contributed to researching, planning, executing, testing, breaking, rectifying, re-testing, and launching London 
Special thanks to Henry Be for the cover image of this article!
Disclaimer
This is a developing and advancing highly technical domain. If you decide to act on the suggestions in this article and continue your engagement, ensure you comprehend how it affects you. It’s important to recognize that risks are involved, including but not limited to risks like unforeseen bugs. By opting to follow these recommendations, you accept the risks of the outcomes on your own. This article and its suggestions do not constitute a sale of any kind, nor do they create any warranties, including but not limited to anything associated with the Ethereum network or the Ethereum clients referenced herein.
