Constantinople: who, what, where, how?


Ethereum’s latest network upgrade, Constantinople, will take place at block number 7,080,000, which is predicted to occur on Wednesday, January 16.

The countdown to Constantinople can be tracked on Ethereum explorer, AmberData.


Constantinople contains five distinct upgrades, four of which are designed to optimize performance:

EIP-1234: Constantinople Difficulty Bomb Delay and Block Reward Adjustment

Delays the difficulty bomb for approximately 12 months and decreases block, uncle, and nephew rewards by 33%.  

EIP-145: Bitwise shifting instructions in EVM

Adds native bitwise shifting that reduces cost and improves efficiency of information processing by 10x. At present shift operations can be implemented via arithmetic operators but only at exorbitant cost.  

EIP-1014: Skinny CREATE2

Allows developers to interact with addresses that have yet to be created, opening up possibilities for frictionless onboarding of dApp users and paving the way for state channels.

EIP-1052: EXTCODEHASH opcode

Introduces a new opcode, which returns a hash of a contract’s code, facilitating contract code verification for whitelisting purposes.

EIP-1283: Net gas metering for SSTORE without dirty maps

Increases gas efficiency and reduces complexity of contract storage.  


Of the five upgrades, EIP-1234 has sparked the most discussion. Nevertheless, there is a sense of overwhelming consensus among the Ethereum community that it should proceed as designed and thus is highly unlikely to induce the type of chain split that led to the creation of Ethereum Classic.

The ‘Ice Age’ feature, which makes discovery of satisfactory hashes increasing difficult, was designed to incentivize miners to switch to Ethereum’s Proof of Stake chain once development is finalized. Due to delays in Proof of Stake research, core developers have decided to delay the ‘Ice Age’, thereby allowing blocks to maintain their 10-15 second production time.

EIP-1234 also contains a 33% reduction in issuance, informally referred to as ‘The Thirdening’, moving ether’s inflation rate more in line with that of bitcoin.

In theory this adjustment to the inflation rate should see proportional appreciation in the price of ether as natural sell pressure from miners falls, although whether this has already been priced in and will actually result in a net gain or loss for miner revenue remains to be seen.

Source: (Note: Issuance rate in Serenity phases is yet to be finalized)

Source: Kiran Vaidya

Either way, miners are essentially left without a choice as the upcoming difficulty adjustment on the pre-Constantinople chain will render the network unusable in the coming weeks and months and exchanges are unlikely to create markets for pre-Constantinople ether. Miners could coordinate to delay the difficulty adjustment on the pre-Constantinople chain while maintaining the current issuance rate, but they would likely struggle to attract wider developer support, ultimately rendering their chain worthless.    


As Constantinople is a hard fork, Ethereum node operators must update their clients to the latest version. For geth and Parity, these are v1.8.20 and v2.1.11/2.2.5, respectively.

Any node that fails to upgrade will sync to the pre-fork blockchain and will be unable to send ether or operate on the post-upgrade Ethereum network.

At the time of writing, 15.5% of clients have upgraded. While ostensibly low, the adoption is actually relatively high for a pre-fork state, with remaining node operators expected to follow suit if the fork passes smoothly. The main concern is that miners adopt the upgrade as they are responsible for securing and determining the canonical chain.

Fortunately, owners of ether that do not run full nodes can sit tight and rest easy as there is no action required to claim their holdings on the new chain.

The post Constantinople: who, what, where, how? appeared first on The Block.

Constantinople: who, what, where, how? written by Matteo Leibowitz @ January 14, 2019 Matteo Leibowitz

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