Ethereum London Hard Fork: What You Need to Know

Earlier this year, the Ethereum Foundation deployed the Berlin hard fork, which follows the Istanbul and Muir Glacier updates. These series of updates are part of Ethereum’s broader roadmap to upgrade its network that will culminate in the Serenity upgrade – also known as Ethereum 2.0.

What is the London hard fork about? Stay tuned to learn more about the London update and what to expect for Ethereum moving forward.

Get to know the Ethereum network: Read our complete guide Ethereum.

What is the Ethereum London Hard Fork?

With every new hard fork, the Ethereum network gets closer to its eventual upgrade to its final form of Ethereum 2.0. These code-named updates serve as checkpoints that will ensure the stability and reliability of the network as it prepares for the final upgrade.

As with the previous Berlin update, the London hard fork will see the deployment of another set of EIPs (Ethereum Improvement Proposals). 

The main highlight of the London upgrade will be EIP-1559, which will bring adjustments to the transaction fees on the network.

However, the other EIPs also play a key role in improving the stability and provide the necessary groundwork for the eventual update to Ethereum 2.0.

Interesting fact: Ethereum updates are code-names after Devcon city names – with London being the location for Devcon 1, and Berlin for Devcon 0. 

What updates are included in Ethereum London Hard Fork?

The details outlined within the EIPs are mostly meant for developers and contain technical information that may be challenging for the average user to decipher. 

Nevertheless, we’ll be highlighting the main points of the London EIPs without going too technical into each one.

EIP-1559: Fee market change for ETH 1.0 chain

Perhaps the most anticipated update from the London hard fork is EIP 1559, which is set to introduce a base fee in blocks on the Ethereum network which will track the gas prices based on the demand and traffic of the current block space. 

What this means is essentially allow wallets and users to have a more accurate estimate of how much a transaction actually costs. 

EIP-3198: BASEFEE opcode

EIP-3198 was engineered as a companion proposal to the previous EIP-1559. EIP-3198 basically enables smart contracts to access an opcode called BASEFEE, which will help with submitting fraud proofs, therefore, creating a kind of trustless gas price derivatives. 

EIP-3529: Reduction in refunds

On the Ethereum network, gas refunds introduce variances in block execution time. 

Before the London update, up to 50% of refunded gas fees could be utilized to process computations within the same block – meaning that in practice, the maximum block size can have a variance of up to 1.5 times the gas limit. 

The intention behind EIP-3529 is to offset the block variances introduced by EIP-1559 by allowing blocks to use up to twice the current gas limit. This is done by reducing the value known as the “execution refund” from a maximum of 50% down to 20%. 

If this all sounds confusing, you can read more about it by visiting this blog.

EIP-3541: Reject new contracts starting with the 0xEF byte

Simply put, EIP-3541 makes it impossible for any new smart contracts starting with the 0xEF byte to be deployed on the Ethereum network. 

This is a simple, yet important update that lays the groundwork for overall long-term improvements for the Ethereum Virtual Machine (EVM).

EIP-3554: Difficulty Bomb Delay to December 1st, 2021

On the Ethereum network, a Difficulty Bomb, also referred to as an ice age, is a built-in mechanism to halt, or freeze mining as the network transitions to the proof of stake (PoS) protocol.

Now since the network is technically not ready to transition to PoS, there is a need to delay the so-called “bomb” from going off until the time is right. EIP-3554 is a proposal that functions to simply push the timer back until December 2021 – in which either the transition is ready to happen, or another update will be deployed to delay it once more.

What’s next for Ethereum?

As I prefaced in the beginning, the London hard fork is a part of a series of incremental updates to the Ethereum mainnet that will eventually culminate in the upgrade to Ethereum 2.0. 

Again, these EIPs serve as checkpoints for the Ethereum network and are necessary to prepare not only the network, but also the developers, miners, and all other parties involved in the Ethereum ecosystem.

Ethereum 2.0 will see the transition of the network to proof of stake protocol, a monumental change to the underlying network architecture.

The Berlin, London, and soon-to-come Shanghai hard forks all serve the purpose of laying the groundwork for that final jump to Eth2. 

Missed the last Ethereum update? Click here to read our guide for Ethereum Berlin. 

That said, stay tuned for more Ethereum updates in the future!

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