Blockchain technology remains a relatively new concept, but Ethereum has travelled a long way in a short space of time. One of the most high-profile and recognizable examples of cutting-edge blockchains, Ethereum has undergone major forks since its inception in 2014 and public launch in 2015. Though exact dates and milestones may have been altered along the way, the team behind Ethereum has endeavoured to adopt a system of ongoing development that aims to enhance security, improve functionality and user experience, and work towards optimal decentralisation. This guide will outline the major forks on Ethereum’s journey thus far.

The early days

When Ethereum first came into being, the plan was to execute its evolution through four key stages. The first phase, which was utilised as a type of beta version, comprised Olympic and Frontier. In essence, Olympic, which launched in July 2015, was an opportunity for developers to get an insight into what Ethereum would look and feel like once it was available. At the time, developers were encouraged to test four main areas, including:

  • Transaction activity
  • Virtual machine usage
  • Mining powers
  • General punishment

The next stage, Frontier, was designed to analyse characteristics of Ethereum, with particular focus on:

  • Block rewards
  • Gas usage
  • Canary contracts
  • User experience

Homestead (2016)

Once the beta phase had been completed, the next step was Ethereum’s first scheduled fork, Homestead, in 2016 at block number 1,150,000. This fork was designed to facilitate three primary improvements from the beta model, which included:

  • Removing canary contracts
  • Introducing new codes via Ethereum’s language, Solidity
  • Implementing the use of the Mist wallet, facilitating ETH transactions and smart contracts

DAO (2016)

When exploring major forks, it’s worth noting the DAO fork in 2016, which was unexpected and unplanned. This fork was implemented following the hacking of DAO, an organization that lost $50 million worth of ETH having raised a total of $150 million through token sales. This fork is significant in the development of Ethereum because it prompted the Ethereum community to make a decision about how to react to the situation. The community opted to hard fork the blockchain to restore funds and to protect against future threats. This decision was not backed universally, and some people continued to use the original chain. This chain, which had been hacked, with the $50 million worth of ETH not replaced or returned, became known as Ethereum Classic (ETC). The Classic chain was a weaker chain, which was vulnerable, and as such, the majority of users and developers focused on the forked chain. The missing $50 million was returned to its owners, and the forked chain became the blockchain we now recognise as Ethereum.


Currently in progress, the Metropolis fork is the third phase, and the final step towards Ethereum Serenity. Metropolis comprises two key forks: Byzantium and Constantinople.


Implemented in October 2017 at block 4,370,000, Byzantium contained nine Ethereum Improvement Proposals, or EIPs. The most significant included:

  • EIP 100: Modifying the formula to analyse the complexity of a block, taking uncle blocks into consideration, and increase stability.
  • EIP 658: Introducing transaction receipts with a status field that confirmed success (1) or failure (0).
  • EIP 649: Continued development of the Difficulty Bomb concept, which was introduced in an early form in 2015 with a view to eventually encourage Proof of Stake, rather than Proof of Work.


The second stage of the Metropolis fork, Constantinople is currently underway. The fork was scheduled for early 2019, and Ethereum confirmed the upgrade would take place on February 28th at block number 7,280,000. There are five main EIPs to consider:

  • EIP 145: Revised Bitwise shifting instructions to facilitate easier information processing and reduce the cost of smart contracts.
  • EIP 1052: Simplification of smart contract verification. Prior to Constantinople, it was necessary to extract the entire code to verify the smart contract.
  • EIP 1014: This EPI was launched by Vitalik Buterin, the founder of Ethereum, with a view to enabling state channels and improving the security of off-chain transactions.
  • EIP 1283 SSTORE: Initially, this EIP was designed to reduce gas costs; however, it has since been reviewed due to a potential flaw and will be addressed in the subsequent St Petersburg fork.
  • EIP 1234: This EIP has two main aims – reducing block rewards from 3ETH to 2ETH and delaying the Difficulty Bomb, paving the way for a further vote in the next year.
  • The Constantinople upgrade is also due to provide a form of emergency off-button, which can be activated to delay scheduled modifications in the event of something going wrong.

The future of Ethereum

The desired destination for Ethereum is Serenity, but it is anticipated that further forks will take place before reaching this final point. Over the course of time, the Ethereum roadmap has been adjusted and altered, and the next stop is believed to be Istanbul. The fork will be predominantly shaped by decisions made based on program POW (Proof of Work). The most crucial aspect of Serenity is shifting from Proof of Work to Proof of Stake, but this is not the only major update. Serenity’s updates are expected to come in phases, with key developments including the introduction of the beacon chain and sharding, a complex scaling method, which breaks the network into fragments known as shards. There will also be a move from EVM (Ethereum Virtual Machine) to eWASM (Ethereum-flavored Web Assembly).

Ethereum has travelled a long way in a relatively short amount of time, with major forks in the past and changes still to come.

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Author: Team