Constantinople hard fork is successful, and the block reward is reduced to 2ETH

After the testnet upgrade failure and the delay caused by the sudden vulnerability, Ethereum finally ushered in the second hard fork of the "Metropolis" stage. The Constantinople hard fork arrived at the 7280000 block height at 3:53 am on March 1 , Beijing time , https://etherscan.io/block/countdown/7280000. In the next few minutes, the block was packaged smoothly, EIP-1234 took effect, and the block reward was reduced from 3 ETH to 2 ETH, but the network difficulty did not decrease significantly, temporarily maintaining at 20 seconds. At 9 am on March 1, Beijing time, the block time dropped to 19.5 seconds, and there was no sign of other forks for the time being. It is understood that the main purpose of the reduction is to reduce ETH inflation and make miners more willing to transfer to the future PoS Ethereum.

However, the Constantinople hard fork experienced unprecedented difficulties. Although Ethereum has undergone multiple hard fork upgrades and has experienced many problems, such as the birth of ETC and the postponement of the Byzantium hard fork, the situation this time is particularly severe.

In early October 2018, Ethereum conducted a Constantinople hard fork on the cross-client testnet Ropsten, but then announced that the testnet upgrade failed due to consensus issues. However, Mars Finance found that since the block height of 4,230,000 on October 13, the block reward of the testnet Ropsten has been reduced from 3 ETH to 2 ETH, indicating that the testnet has successfully completed the Constantinople upgrade, or partially implemented the upgrade. On October 19, the core developers of Ethereum said that the Ethereum mainnet will be hard forked in January 2019.

On December 7, at the Ethereum Core Developer Conference, developers decided to activate the hard fork at 7,080,000 on the Ethereum main chain, around mid-January 2019.

On January 15, 2019, 30 hours before the 7,080,000 block height, Ethereum developers received a report and determined that the scheduled Constantinople hard fork would introduce a smart contract security vulnerability, and urgently suspended the fork procedure.

On the evening of January 18, Ethereum core developers including Vitalik Buterin, Afri, and Martin decided to postpone the Constantinople hard fork to block height 7280000, and stated that they would conduct a double fork to remove the EIP-1283 proposal with security vulnerabilities. These two hard forks are called "Constantinople" and "St. Petersburg" hard forks.

In mid-February, the difficulty of the Ethereum network gradually increased, the block time increased, and the block height of 7280000 was passively postponed from the originally expected February 27 to March 1.

Mars Finance learned that in addition to the five update plans originally planned to include EIP-145, EIP-1052, EIP-1283, EIP-1014 and EIP-1234, this hard fork will also activate the Ethereum Create2 function , which has also recently caused controversy in the Ethereum community. Jason Carver, a developer at the Ethereum Foundation, said that "the new function of Create2 allows developers to replace self-destruct contracts and thus change the rules." According to Mars Finance, Create2 allows developers to "control" newly generated contract addresses, allowing DApp developers to generate contract addresses without actually deploying contracts. Although Vitalik later came forward to say that there was no problem with the Create2 he proposed, Peckshield researchers said that if used on a contract with a self-destruct code, once the contract self-destructs, compared to CREATE with a serial number that cannot create a duplicate address, using CREATE2 can update the code at the same address without the user's knowledge.

In addition, some people in the Ethereum community accused Ethereum core developer Afri Schoedon of deliberately delaying the Ethereum Constantinople hard fork several times due to conflicts of interest, which eventually led to Afri's disillusionment with the Ethereum community and his public announcement of leaving the Ethereum development team. Afri Schoedon is an Ethereum core developer and release manager of Parity, the main Ethereum client. He has worked for four years without pay in important tasks such as hard fork coordination and testnet construction. Mars Finance believes that his departure will inevitably affect the stability and future development of the Ethereum development team.

Ethereum is undergoing changes, and the Constantinople hard fork is an extremely important step in the transition to PoS consensus. Currently, Ethereum Constantinople and St. Petersburg hard forks have been completed. After the next Istanbul hard fork, Ethereum will begin to truly shift to PoS.