Ethereum The Ethereum Classic “Phoenix” Hard Fork: Historical Background and Objectives
Ethereum The “Phoenix” hard fork of Ethereum Classic (ETC) was successfully activated on or around May 31 or June 3, 2020, at block number 10,500,839.This hard fork marked a significant milestone in ETC’s development, with its core objective being to achieve full compatibility between Ethereum Classic and the then-current Ethereum (Ethereum, or ETH) Istanbul network protocol upgrade.This marks the first time that the ETC and ETH chains have achieved complete technical alignment, laying the foundation for future interoperability and ecosystem development.
Ethereum Ethereum Classic was born in the wake of the 2016 DAO incident. Adhering to the principle of “code is law,” it refused to roll back the blockchain to reverse the stolen funds, thereby parting ways with Ethereum, which chose to roll back.Despite these philosophical differences, ETC developers have consistently strived to maintain compatibility with the core protocol of Ethereum in order to leverage its technological advancements and attract developers.
Technical Details and Protocol Improvements
The Phoenix hard fork incorporates a series of key protocol improvements introduced by the Istanbul hard fork (Ethereum), aimed at optimizing network performance, reducing transaction costs, and enhancing security. These improvements include:
- Blake2 compression function F precompile: A new precompile contract has been added for more efficient cryptographic operations.
- Reduced Gas Costs for the alt_bn128 Precompile: Significantly reduced the cost of cryptographic operations related to zero-knowledge proofs (ZKPs), benefiting DeFi and privacy applications.
- Addition of the ChainID opcode: A new opcode has been introduced that allows smart contracts to more securely identify the current chain ID, helping to prevent cross-chain replay attacks.
- Revaluation of Gas Costs for Trie-Size-Related Opcodes: Adjusted the Gas costs for opcodes related to Trie (state tree) size to more accurately reflect their computational resource consumption.
- Reduced Gas Costs for Calldata: Gas costs for call data (Calldata) have been reduced, helping to lower the fees associated with smart contract interactions.
- Rebalancing SSTORE Gas Costs: The gas costs for the SSTORE storage operation have been adjusted to optimize network resource allocation.
Prior to its activation on the mainnet, this upgrade was successfully implemented on the Mordor (March 9, 2020) and Kotti (April 15, 2020) testnets, ensuring a smooth mainnet upgrade.
Development Milestones and Network Challenges
The Phoenix hard fork is the third major hard fork completed by Ethereum Classic within a year, following the “Atlantis” and “Agharta” hard forks.This series of upgrades collectively completed the ETC-ETH compatibility agenda, paving the way for future research and innovation on Ethereum Classic.
However, the network experienced fragmentation following the hard fork. Some clients, such as OpenEthereum and Hyperledger Besu, were incompatible with the Core-Geth and Multi-Geth clients regarding the eth/64 protocol implementation, leading to the formation of factions among network providers.The ETC Core development team recommended that users migrate from the no-longer-supported Parity Ethereum client to Core-Geth. Prior to the hard fork, some developers had also expressed concerns about potential “broken contracts,” unclear gas cost calculations, and a lack of public awareness.
Ethereum What Makes Classic Unique
Although it remains compatible with Ethereum at the protocol level, Ethereum Classic adheres to its own unique path regarding the core consensus mechanism. As of this writing, ETC continues to use the Proof-of-Work (PoW) consensus mechanism, which stands in stark contrast to Ethereum’s shift to Proof-of-Stake (PoS) in 2022.Additionally, during the Thanos hard fork in November 2020, ETC changed its mining algorithm from Ethash to Etchash, with the aim of supporting long-term mining with 3GB and 4GB GPUs and enhancing network security.
Ethereum ETC Classic has a maximum supply of 210,700,000 ETC, a limit set during the Gotham hard fork in December 2017, which ensures its scarcity.
ETC’s Market Performance and Trading Channels
As of August 29, 2026, the real-time price of Ethereum Classic (ETC) ranged from approximately $7.50 to $8.37, with a 24-hour trading volume of approximately $36.6 million.Its real-time market capitalization ranges from approximately $1.18 billion to $1.31 billion, with a circulating supply of about 158 million ETC. Please note that these figures are subject to market fluctuations and are provided for reference only.
As a mainstream cryptocurrency, ETC can be traded on numerous well-known cryptocurrency exchanges worldwide. Users can verify specific trading channels and trading pairs on exchanges that support this coin.
