TL;DR
Ethereum's Arrow Glacier network upgrade delayed the network's difficulty bomb to June 2022. Many previous updates have also extended the deadline for the difficulty bomb. The difficulty bomb, by design, makes mining on Ethereum uneconomical and difficult to do. This feature was intended to motivate the development of Ethereum 2.0 and forced miners to change over to the new Proof of Stake blockchain.
The update contained one Ethereum Improvement Proposal (EIP) delaying the difficulty bomb. An EIP is a proposed change created and reviewed by the Ethereum community. Arrow Glacier is particularly exciting as it looked to be the last extension of the difficulty bomb before Ethereum 2.0's release.
Introduction
While the Arrow Glacier update was not a noticeable change for the average user, it's actually incredibly important. In fact, the network could end up almost unusable without it. Let's look at why and what it has done for users, stakers, crypto miners, and Ethereum 2.0.
What is the Ethereum Arrow Glacier upgrade?
The Ethereum Arrow Glacier Upgrade is a fairly simple update implemented in block number 13,773,000, Dec 9, 2021. Arrow Glacier delays the network's difficulty bomb, allowing developers more time to prepare Ethereum 2.0. Extending the time bomb is a regular aspect of Ethereum updates. It was previously scheduled for December 2021 with the London hard fork, but is came into effect in June 2022.
Arrow Glacier is extremely similar to the previous Muir Glacier upgrade in January 2020, which also delayed the time bomb. They both contain only one Ethereum Improvement Proposal (EIP) that pushes the "ice age" back. The Constantinople, Byzantium, and London updates also included extensions to the difficulty bomb.
What is the Ethereum difficulty bomb?
The Ethereum blockchain originally used a Proof of Work (PoW) consensus mechanism. This meant that users who validate transactions had to use computing power to solve a mathematical puzzle. This process puts a cost on creating consensus and protecting the network from malicious actors.
A difficulty bomb was included that gradually increases the difficulty of these puzzles, making it more costly to mine a block successfully. The difficulty bomb will "explode" and make it almost impossible to validate transactions and add new blocks. It will simply become too costly to mine on the blockchain. The difficulty bomb was added for two reasons:
1. To help motivate the development of Ethereum 2.0 and the move to a Proof of Stake model (PoS).
2. To force miners to upgrade to the new PoS blockchain, as they will not be able to keep mining Ether (ETH) on the old PoW version of Ethereum. This will prevent the creation of two conflicting Ethereum networks through a hard fork.
What is an Ethereum Improvement Proposal (EIP)?
an EIP can propose any improvement or change to Ethereum. Anyone can create an EIP, which the Ethereum community, a board of editors, and Ethereum developers review. To be included in an update, the EIP must pass the approval process. Each EIP contains the technical requirements for a particular change according to a specific EIP format. We briefly mentioned Arrow Glacier contains only one EIP, in this case EIP-4345. Its only goal is to extend the time before Ethereum's mining ice age.
How will Ethereum's Arrow Glacier update affect me?
For the standard user, there won't be any noticeable difference. Block times for confirmation have remained almost constant at around 13 seconds for the past year. If you operate a node or are a miner, you would have had to upgrade your Ethereum client to the latest version. Otherwise, your client will be on the old fork of Ethereum, which will no longer be officially supported by the community.
Closing thoughts
Although Arrow Glacier is a small update, it's a significant one. Without it, the network would become too costly to mine and slow to use. It's also a fairly exciting one for the Ethereum community. If it happens to be the last extension to the difficulty bomb, Ethereum 2.0 has come about with the help of this upgrade.