The Ethereum (ETH) developers canceled the deployment of the Constantinople hard fork. They urged everyone who had upgraded to upgrade again and remove Constantinople due to a critical security bug discovered in EIP-1283.
Essentially, the reduction of transaction fees in EIP-1283 opened the door for reentrancy attacks where hackers could steal all of the Ethereum (ETH) out of smart contracts. Not all miners received the memo though, and the Ethereum (ETH) chain split: 94 TH/s of mining power split off into the ‘erroneous’ Constantinople chain at block 7.08 million.
This happened because miners who had upgraded to Constantinople had to upgrade again to fix the problem. Without the second upgrade, they ended up on the wrong chain. The total mining power on the actual Ethereum blockchain is 180 TH/s, so a significant fraction of Ethereum’s total mining power was on the wrong chain for a period of time.
It is unknown how this chain split has evolved since there is no good way to monitor it, and the page monitoring the chain split has been stuck at 94 TH/s for the erroneous Constantinople chain for more than two days, indicating it is no longer being tracked.
Certainly, miners who made the mistake of being on the Constantinople chain lost mining revenue, and there were possibly transaction errors due to there being two competing blockchains. Further, this mess up likely lowers confidence in the Constantinople hard fork, making a permanent chain spit when Constantinople deploys more likely.
The Ethereum (ETH) Constantinople hard fork is now scheduled for block 7.28 million, which should occur on Feb. 27.
The Constantinople hard fork will no longer include lower transaction fees, which was one of its main selling points.
Additionally, the Ethereum (ETH) block reward will still be lowered from three ETH to two, beginning the planned transition away from proof of work (PoW) to proof of stake (PoS).
Further, a vote is underway to include ProgPoW, which disenfranchises ASIC miners, and nearly 99 percent of votes are for ProgPoW. The slashing of the block reward by 33 percent, lack of confidence in the fork, potential for blocking ASICs, and planned transition to PoS longterm may be enough to cause a miner revolt and chain split when Constantinople does deploy in late February.
The Ethereum (ETH) market is in the red following the delay of the Constantinople hard fork and chain split. Since the news broke about the Constantinople delay, Ethereum (ETH) has declined from $130 to $118 (nine percent).
Even before the Constantinople delay, the fork was weighing heavily on the market, and since Jan. 5 Ethereum (ETH) is down from $160 (26 percent).
The weeks ahead look to be turbulent for Ethereum (ETH) since the fork is becoming more controversial than ever due to the delay, chain split, and removal of lowered transaction fees. There is no way to avoid this hard fork since the difficulty bomb is already going off, causing block times to increase from 14 seconds to 15.5 seconds currently. By the time the Constantinople fork is deployed in late February, block times will be approaching 20 seconds, causing significant losses of revenue for miners and much higher transaction fees on the Ethereum (ETH) network.