On Dec. 8, Ethereum successfully completed the Istanbul hard fork at block 9,069,000. This was the third system-wide upgrade in 2019 after St. Petersburg and Constantinople and overall eighth hard fork.
The upgrade included six Ethereum Improvement Proposals viz. 152, 1108, 1344, 1844, 2028, and 2200.
As per ConsenSys blog post, the main issues addressed by these EIPs involves gas costs, interoperability with equipment hash-based proof-of-work (PoW) cryptos like Zcash, and denial-of-service attack resilience.
Just before the Istanbul has to take place, ethereum client Parity released an urgent message asking the client users to upgrade to the latest version of Parity Ethereum, issuing an emergency patch, before the hard fork.
The fix was simple but ethereum core developer Hudson Jameson said if one or two major changes or mining pools would have remained on the old chain, it would have caused confusion and “in a more severe case double spends.”
Negative Consequences of the Network Upgrade
Now, while the upgrade was technically successful, Antoine Le Calvez data engineer at blockchain analytics company Coin Metrics notes that it wasn’t without negative consequences.
He pointed out that some of the EVM operations were repriced to cost more in fees. This has affected some of the smart contract activity. Interestingly, four of the six EIPs were focused on repricing and reducing the gas cost.
Following the hard fork, on the global level, Le Calvez found that smart contract calls running out of gas have become much more frequent. Failure rates have increased 4 times.
He also found some exchanges are also affected. Cryptocurrency exchange Gemini is one of them that he says hasn’t been able to move user deposits to its hot wallet after the Istanbul upgrade. Each of its attempts is resulting in an out-of-gas error.
However, Gemini says this is because its testnet and mainnet sweepers are a bit different and they are working on replacing them.
“Instead of building a full fidelity test, we calculated the necessary gas limit increase and applied it last week,” explained the exchange. They had to add even more gas after the exchange hit an old Solidity quirk. But now the sweeps are “proceeding normally!”