Ethereum Phases Overview: What Happens After The Ethereum Merge?

Ethereum Phases

During the ETHCC Paris conference, Ethereum co-founder Vitalik Buterin said that after the much-anticipated merge (wherein the protocol will transition from PoW to PoS), Ethereum would be 55% complete. Following that, people started speculating about Ethereum’s development and product roadmap timelines. Today, we give you a brief idea about what Ethereum will eventually look like in the future. To do that, we will go through all the Ethereum phases individually.


Ethereum phases: The journey from Ethereum 1.0 to Ethereum 2.0

The core Ethereum devs always wanted to launch the protocol in multiple phases. Since Ethereum is such a complex protocol capable of supporting a diverse ecosystem, it must be developed carefully to ensure security, scalability, and decentralization. By launching in stages, the developers would be able to test out each and every aspect of the protocol in the real world.

These Ethereum stages are as follows:

  • Frontier
  • Homestead
  • Metropolis
  • Serenity.

The Frontier, Homestead, and Metropolis upgrade could be grouped under “Ethereum 1.0,” while Serenity is Ethereum 2.0 – or Consensus Layer as we call it today. So let’s go deeper into these Ethereum milestones.

Ethereum 1.0: Building the foundation

Ethereum Frontier

  • Initiated at: Genesis
  • Date: 30 July 2015
  • Main purpose: Prepare the foundation for miners and developers.

During launch, the version of Ethereum we all saw was “Frontier.” This is a very minimal form of the network. The primary purpose of this stage was to:

  • Allow miners to set up their rigs and kickstart mining.
  • Launch the ETH token to be traded in exchanges.
  • Developers could start testing out DApps, albeit in minimal settings.

During the initial phase, Ethereum blocks had a gas limit of 5,000. This limit was lifted in September 2015, at block number 200,000 via a hard fork called “Frontier thawing.” Following this, it was finally possible to conduct transactions (which cost 21,000 gas) on Ethereum. The fork also introduced a “difficulty bomb” – a piece of code that would eventually make Ethereum impossible to mine via PoW.

Ethereum Homestead

  • Initiated at: Block number 1,150,000
  • Date: 14 March 2016
  • Main purpose: Make Ethereum safer and more stable.

Homestead is basically a safer and better version of Frontier, which had these three main protocol updates:

  • EIP-2 Main homestead hardfork changes
  • EIP-7 Hardfork EVM update: DELEGATECALL
  • EIP-8 devp2p forward compatibility

These upgrades made Ethereum more developer-friendly and allowed the network to drive further protocol upgrades. However, the network remained in the Beta phase.

Ethereum Metropolis

  • Initiated at: Block number 4,370,000
  • Date: 16 October 2017
  • Main purpose: Increase network functionality to promote DApp creation and increase network utility.

The Metropolis phase was the final stage of Ethereum 1.0. At this point, Ethereum had already started experiencing immense network utility due to the ICO boom. Several updates were deployed during this stage, which is why the metropolis Ethereum release was split into the following forks:

  • Byzantium
  • Constantinople
  • Istanbul


  • Initiated at: Block number 4,370,000
  • Date: 16 October 2017

The Ethereum Metropolis Byzantium fork brought in the following upgrades:

  • Ethereum metropolis mining rewards were reduced from 5 ETH to 3 ETH.
  • Delayed the difficulty bomb, giving miners more time to wrap up their operations.
  • Added cryptographic provisions to allow layer-2 scaling.


  • Initiated at: Block number 7,280,000
  • Date: 28 February 2019

Two years after the Ethereum metropolis release, we had the Constantinople fork. The main objectives here were:

  • Give Ethereum the ability to interact with addresses that haven’t been created yet.
  • Optimize the gas costs of certain solidity functions to make smart contract execution less bulky and expensive.


  • Initiated at: Block number 9,069,000
  • Date: 8 December 2019

The Istanbul fork was the last stage before Serenity and Ethereum 2.0. During this stage, Ethereum managed to:

  • Further optimize gas costs within the EVM.
  • Make the network more resilient against DDoS attacks.
  • Make smart contracts more creative and functional.
  • Create layer 2 scaling solutions using zk-SNARKS and STARKS. These zero-knowledge cryptographic proofs as popularized by Zcash.

Ethereum 2.0: The green and scalable world computer

The fourth stage is called Ethereum Serenity, aka Ethereum 2.0. This is the stage we are going through right now. Before we continue, let’s look at the state of the Ethereum ecosystem right now. Along with Bitcoin, Ethereum is one of the two biggest crypto protocols in the world, and it has been for quite some time. Its public and programmable blockchain has allowed developers worldwide to create applications at the cutting edge of innovation.

2020 saw the rise of decentralized finance (DeFi), championed by MakerDAO, Curve Finance, Uniswap, etc. The idea of yield farming and decentralized swaps led to a multi-billion dollar sector.

2021 saw the rise of non-fungible tokens (NFTs). Not only did this space attract immense mainstream attention, but projects like Bored Ape Yacht Club have become cultural staples. NFTs were also instrumental in laying down the groundwork for the metaverse.

So, in short, Ethereum has proven itself to be immensely utilitarian. Now, as we move into Ethereum 2.0, here are the main design goals.

  • Transition protocol consensus from PoW to PoS. As you may already know, PoW (or proof-of-work) is a very resource-hungry mechanism that damages the environment. PoS (or proof-of-stake) makes the mining process virtual and exponentially greener.
  • Enable sharding – a layer 1 scalability technique that breaks down the state of the network in smaller chunks called “shards.” These shards could be processed parallelly, making the entire network highly scalable.

Breaking down Ethereum 2.0

There’s one thing you need to know about these two changes, they aren’t easy to implement. Both require you to change Ethereum’s code at a fundamental level. This is not something that you can just implement randomly. Ethereum is valuable because the developers and miners work tirelessly to increase network utility, performance, and security. You can’t change everything one fine day and hope for them to adjust accordingly. Plus, Ethereum hosts multiple multi-billion dollar ecosystems. If any of these changes break the entire network, many people could lose a lot of money.

So, to ease in the changes, we had the progressive upgradation of the Ethereum 1.0 phase. The Ethereum Serenity release has been broken down into four phases to continue this same ethos.

  • Phase 0: Beacon Chain
  • Phase 1: Deploying sharding
  • Phase 1.5: PoW Ethereum chain becomes a shard chain.
  • Phase 2: Shard chains become fully functional.

1. Ethereum 2.0 – Phase 0

  • Initiated at: Beacon Chain block number 1
  • Date: 1 December 2020
  • Main purpose: Build the validator set for Ethereum PoS


During Phase 0, Ethereum launched the beacon chain. This is the proof-of-stake chain that has the staking contract. Whoever wishes to become a PoS validator in Ethereum 2.0 must lock up their stake in the beacon chain. Think of the beacon chain as a diary that notes the addresses of all validators and their stake.

Ethereum phases

Snapshot of beacon chain stats:

  • Active validators: 410,299 
  • Staked ether 13,129,457 ETH 
  • Average balance 33.67 ETH


Eventually, the beacon chain will be combined with the main Ethereum chain during the event called “Merge.”

NOTE: As of writing, the following phases have not been initiated yet.

2. Ethereum 2.0 – Phase 1

  • Initiated at: N/A
  • Date: N/A
  • Main purpose: Initiating sharding


Phase 1 will introduce shard chains and initiate layer 1 scalability. In Ethereum 2.0, the main state will be broken down into 64 shard chains alongside the beacon chain.

3. Ethereum 2.0 – Phase 1.5

  • Initiated at: N/A
  • Date: N/A
  • Main purpose: Incorporate Ethereum PoW into sharding


Shortly after shard chain deployment, Ethereum will go through phase 1.5. During this phase, the Ethereum PoW chain will become one of the 64 shard chains running alongside the beacon chain. 

4. Ethereum 2.0 – Phase 2

  • Initiated at: N/A
  • Date: N/A
  • Main purpose: Lower barriers to entry and explosive scalability.


Phase 2 will have multiple technological innovations that will change the face of the Ethereum ecosystem. These innovations include:

  • Cross-shard interoperability.
  • Individual shard chains to handle transactions and smart contract operations
  • Let developers code smart contracts in any language they want – not just solidity.

Ethereum phases alternative: Vitalik’s new timeline

During ETHCC Paris, Vitalik Buterin gave an alternative and updated roadmap for Ethereum 2.0.

  • The Merge: The first stage is the much-anticipated Ethereum Merge, which combines the beacon and OG Ethereum chains. 
  • The Surge: This stage introduces sharding into Ethereum
  • The Verge: Optimize storage and reduce node size by implementing Verkle Trees – an improved version of Merkle Trees. Merkle trees are data structures that store data efficiently.
  • The Purge: Eliminate historical blockchain data and reduce the hard drive space required to download and maintain the chain for validators.
  • The Splurge: Series of miscellaneous upgrades which ensure the network runs smoothly.


Following these stages, Vitalik expects Ethereum to process 100,000 transactions per second.

In Closing

Ethereum is one of the most remarkable inventions of our time. The original vision was for it to be a decentralized world supercomputer. This will only be possible if Ethereum can scale up significantly to meet its overwhelming demand. The stages of Ethereum defined above helps us understand the challenging roadmap that the protocol needs to follow to deliver on its promises.