The Ethereum network will undergo a scheduled upgrade at block number 13,773,000, which is expected to take place on Wednesday, December 8, 2021. The exact date may change due to variable block times and timezones. Please update your node before Sunday, December 5, 2021 to accommodate the variable block times.
What is Arrow Glacier?
Similar to Muir Glacier, the Arrow Glacier network upgrade adjusts the parameters of the Ice Age/Difficulty Bomb, delaying it by several months. This adjustment has also been made in previous network upgrades like Byzantium, Constantinople, and London. No other changes are made as part of Arrow Glacier.
The difficulty bomb only affects Proof of Work networks, so it exists only on the Ethereum mainnet and the Ropsten test network. With the progress towards Ethereum’s transition to Proof of Stake, the decision was made to only delay the bomb on the mainnet for now and attempt the Proof of Stake transition on Ropsten before the bomb affects that network.
To learn more about Arrow Glacier and the history of the difficulty bomb, refer to the Ethereum Cat Herders’ explainer blog post.
To ensure compatibility with the Arrow Glacier upgrade, node operators need to update their Ethereum client version to one of the options listed below:
Note: OpenEthereum, which was previously announced as deprecated, has released support for Arrow Glacier under version number 3.3.0-rc.14. You can download it here.
For now, we recommend following the prior deprecation warnings and choosing an alternative client software. If you decide to use OE for the Arrow Glacier upgrade, please exercise caution and independently review the codebase changes before using it in a production environment.
Upgrade Specification and EIPs
The complete specification for the upgrade can be found in the execution-specs repository here.
The upgrade includes a single EIP: EIP-4345: Difficulty Bomb Delay to June 2022.
As an Ethereum user or ether holder, do I need to take any action?
If you use an exchange, a web wallet service, a mobile wallet service, or a hardware wallet, you don’t need to do anything unless you are instructed to take additional steps by your exchange or wallet service.
As a node operator or miner, what do I need to do?
Download the latest version of your Ethereum client from the table above.
What happens if I am a miner or node operator and I do not participate in the upgrade?
If you use an Ethereum client that is not updated to the latest version (listed above), your client will sync to the pre-fork blockchain after the upgrade. You will be stuck on an incompatible chain that follows the old rules, and you won’t be able to send Ether or operate on the post-upgrade Ethereum network.
What is a network upgrade in Ethereum-land?
A network upgrade is a change to the underlying Ethereum protocol that introduces new rules to improve the system. The decentralized nature of blockchain systems makes network upgrades more challenging. Network upgrades in a blockchain require cooperation and communication with the community, as well as the developers of various Ethereum clients, to ensure a smooth transition.
What happens during a network upgrade?
Once the community agrees on the changes to be included in the upgrade, the protocol changes are implemented in different Ethereum clients, such as geth, Erigon, Besu, and Nethermind. The protocol changes are activated at a specific block number. Nodes that haven’t been upgraded to the new ruleset will continue on the old chain with the previous rules.
Why “Arrow Glacier”?
While we have been using Devcon names for recent network upgrades, we decided to change the nomenclature for an upgrade that only delays the bomb. To emphasize the nature of the upgrade, which is pushing back the “Ice Age,” we chose a glacier-themed name, hence Muir Glacier.
This upgrade follows a similar pattern. Since the transition to Proof of Stake is approaching, we selected a retreating glacier as the inspiration, hence Arrow Glacier 🏔!
We extend our gratitude to the Ethereum community and all Ethereum developers across different clients and platforms who contribute thoughts, input, and contributions. This might be the last network upgrade on Ethereum before the transition to Proof of Stake. Let’s go!
Special thanks to Harshil Gudka for the cover image.
This is a highly technical space that continues to evolve. If you choose to implement the recommendations mentioned in this post and continue participating, ensure that you understand how it affects you. Be aware that there are risks involved, including potential unexpected bugs. By implementing these recommendations, you assume the risks and consequences. This post and recommendations do not constitute a sale and do not provide any warranties related to the Ethereum network or the Ethereum clients discussed.